Dissertations / Theses on the topic 'Organic Hybrid Porous Materials'

In this PhD thesis, different types of hybrid organic-inorganic materials were studied as solid sorbents for the carbon dioxide capture, in order to give additional hints to the comprehension of phenomena playing an important role in CO2 adsorption processes. In the first part, hybrid organic-inorganic SBA-15 silicas functionalized with variable amount of amino groups were studied aiming to evaluate the influence of the different basic species on CO2 capture ability. Afterwards, it was decided to study the influence of siliceous support properties on the adsorption process. For this purpose, silica-based materials with different structure, morphology and particle size were selected and tested in the same experimental conditions, aiming to understand the effect of their physico-chemical properties on the CO2 adsorption. On one side MCM-41 silica-based materials with different particle diameter, passing from micrometric to nanometric scale, were considered, in order to study the size effect of the support on the adsorption properties. Furthermore, the effect of the porosity was evaluated by using as adsorbent a non-porous material (Stöber silica) and comparing the obtained results with those of MCM-41-based materials. Finally, the possible use of silica-based materials as catalyst for the carbon dioxide transformation into more useful products was studied. In particular, heterogeneous Cu-based catalyst supported on SiO2 have been studied as for the promotion of hydrogenation reaction of CO2 to formic acid.

The aim of this project was to prepare a series of silica materials based on sol-gel processing of alkoxysilanes using glucose and glycerol as templates for potential applications in membrane design for pervaporation. The materials were characterized using structural and dynamic techniques to gain information about the effect of the templates on the formation of micro- and mesoporous silicates. The interaction between templates and silica matrices were investigated using FTIR, Raman Spectroscopy, Solid State NMR Spectroscopy, Physisorption and SEM. Close contact between templates and silica networks was observed by NMR cross polarization studies. The chemistry was then extended to prepare hybrid organic-inorganic silica materials by introducing organic ligands, with glycerol as a template to control the porosity of the hybrid materials. By varying the ligand as well as the template, the physical properties of the gel can be controlled. Composites of hydroxypropylcellulose, HPC, and silica were also prepared and characterized. There was no phase separation during sol-gel processing suggesting HPC was dispersed homogenously in the silica matrices. This was also confirmed by solid state NMR. Temperature dependence showed some indications of conformational change in the HPC within the silicate, above 308K. The transport properties of the hybrid materials were observed by monitoring the diffusion behaviour of water and several selected solvents using Pulsed Field Gradient NMR. The self-diffusion of water and the organic solvents in the hybrid silica materials were two to three orders of magnitude smaller than in the liquid bulk suggesting restricted diffusion at the pore surface. The effect of surface polarity also contributed to water and solvents diffusivities. The temperature dependence of diffusion was useful to derive the activation energy whereas the dependence on NMR observation time provided information on both tortuosity and pore connectivity of the hybrid silica materials. The hybrid silica membranes were prepared by spin coating of polymeric silica sol on top of a macroporous alumina support after being occluded by colloidal silica. It was then used for pervaporation of water ethanol mixtures. The results implied that separation factor increased as the temperature increased. However permeate fluxes were less affected.

[ES] El trabajo de investigación descrito en la presente Tesis Doctoral ha sido desarrollado en el marco del proyecto europeo MULTI2HYCAT (grant agreement N. 720783) y se ha centrado en la síntesis y caracterización de materiales mono- y multi-funcionales que presentan sitios catalíticos ácidos, básicos o redox. Diferentes líneas de investigación han sido desarrolladas en paralelo para obtener distintos materiales híbridos que serán empleados en diferentes procesos catalíticos, en línea con las necesidades de los socios industriales del proyecto. Debido a la naturaleza colaborativa del proyecto, cada miembro académico se ha en-centrado en un aspecto del desarrollo de los materiales. Es por ello que el Instituto de Tecnología Química (ITQ-CSIC), donde se ha llevado a cabo esta Tesis Doctoral, se ha centrado en la síntesis de los catalizadores híbridos. Por ello, parte de la caracterización descrita en el Capítulo 3 se ha llevado a cabo en la Università del Piemonte Orientale (IT), durante una estancia de un mes. Ademas, algúnos resultados catalíticos descritos en los Capítulos 3 y 5 han sido obtenidos por la University of Southampton (UK). En el Capítulo 3, se ha descrito la síntesis de dos catalizadores heterogéneos híbridos que presentan moléculas de ácido aril-sulfónico en su composición. En uno de ellos, el anillo aromático presentará átomos de flúor en posición 2, 3, 5, 6. Se han llevado a cabo dos estrategias de síntesis multi-etapas, a través de la síntesis de los precursores alkoxi-silanos, a través de procesos de condensación junto a un precursor de sílice (en ausencia de agentes directores de estructura, a pH neutro y temperaturas bajas) y de una reacción de tethering. Los materiales híbridos han sido caracterizados a través de dife-rentes técnicas. Las propiedades texturales, la estabilidad térmica y la composición química de los catalizadores ha sido estudiada. Además, moléculas sondas han sido adsorbidas en los materiales hibridos y las interacciones entre ellos han sido estudiadas a través de espectroscopias FTIR y RMN multi-nuclear. El catalizador hibrido en que el anillo aromático estaba fluorado resultó ser el más activo catalíticamente en la reac-ción de formación de acetal entre benzaldehído y etilenglicol. Una versión de los hí-bridos en que la superficie había sido pasivada con grupos metilos también fue obteni-da. Las propiedades de los materiales híbridos pasivados fueron comparadas, para po-der estudiar el efecto de la polaridad de la superficie del soporte sobre la actividad catalítica. En el Capítulo 4 se describe la síntesis de órgano-catalizadores híbridos obtenidos por anclaje de precursores de silicio funcionalizados con grupos básicos sobre un soporte del tipo MCM-41. Los catalizadores han sido caracterizados y empleados en diferentes reacciones de formación de enlaces C-C, como la condensación de Knoevenagel y la adición de Michael. Los catalizadores híbridos han sido empleados en la condensación entre furfural y metil isobutil cetona. El catalizador más activo ha sido seleccionado para ser funcionalizado posteriormente con nanoparticulas de paladio y empleado en un proceso catalítico en cascada. Mecanismos de reacción han sido pro-puesto para cada proceso catalítico. El efecto beneficioso debido a la presencia de los grupos silanoles en la superficie del soporte también fue analizado. En el Capítulo 5, la síntesis de catalizadores híbridos multi-funcionales fue descrita. Basándose en los resultados obtenidos en el Capítulo 4, se ha preparado un catalizador que presente grupos aminopropil- y nanopartículas de paladio. Las propiedades estructurales y texturales han sido estudiadas. Además, a través de la microscopia electrónica de transmisión, la distribución dimensional de las nanoparticulas ha sido estimada, resultando en un tamaño medio equivalente a la dimensión de los canales mesoporosos del soporte, MCM-4
[CA] El treball de recerca descrit en aquesta tesi doctoral es va desenvolupar en el marc del projecte europeu MULTI2HYCAT (grant agreement N. 720783) i se centra en la sínte-si i la caracterització de catalitzadors híbrids mono i multifuncionals amb àcid, base o redox actius llocs. S'han desenvolupat diverses línies d'investigació en paral·lel per dissenyar múltiples catalitzadors híbrids per a diferents processos catalítics, basant-se en les necessitats dels socis industrials. A causa del caràcter col·laboratiu del projecte, cada soci acadèmic es va centrar princi-palment en un aspecte de tot el procés. Institut de Tecnologia Química (ITQ-CSIC), on es va desenvolupar aquesta tesi, està principalment centrat en el disseny i síntesi de catalitzadors híbrids. Per això, part dels resultats de caracterització reportats al Capítol 3 s'han dut a terme a la Università del Piemonte Orientale (IT), durant una estada d'un mes. Alguns dels resultats catalítics reportats al Capítol 3 i al Capítol 5 han estat reali-tzats per la Universitat de Southampton (Regne Unit). En el Capítol 3, s'ha descrit la síntesi de dos catalitzadors heterogenis híbrids que pre-senten molècules d'àcid aril-sulfònic en la composició. En un d'ells, l'anell aromàtic presentarà àtoms de fluor en posició 2, 3, 5, 6. S'han dut a terme dues estratègies de síntesi multi-etapes, a través de la síntesi dels precursors alkoxi-silans, mitjançant pro-cessos de condensació al costat d'un precursor de sílice (en absència d'agents directors d'estructura, a pH neutre i temperatures baixes) i d'una reacció de tethering. Els mate-rials híbrids han estat caracteritzats mitjançant diferents tècniques. Les propietats texturals, l'estabilitat tèrmica i la composició química dels catalitzadors ha sigut estudiada. A més, molècules sondes han estat adsorbides en els materials híbrids i les interaccions entre ells han estat estudiades mitjançant espectroscòpies FTIR i RMN multi-nuclear. El catalitzador híbrid en que l'anell aromàtic estava fluorat va resultar ser el més actiu catalíticament en la reacció de formació d'acetal entre benzaldehid i etilenglicol. Una versió dels híbrids en que la superfície havia estat pasivada amb grups metilos també va ser obtinguda. Les propietats dels materials híbrids passivats van ser comparades, per poder estudiar l'efecte de la polaritat de la superfície del suport sobre l'activitat catalítica. En el Capítol 4 es descriu la síntesi d'organo-catalitzadors híbrids obtinguts per ancoratge de precursors de silici funcionalitzats amb grups bàsics sobre un suport del tipus MCM-41. Els catalitzadors han estat caracteritzats i empleats en diferents reaccions de formació d'enllaços C-C, com la condensació de Knoevenagel i l'addició de Michael. Finalment, els catalitzadors híbrids han estat emprats en la condensació entre furfural i metil isobutil cetona. El catalitzador més actiu ha estat seleccionat per a ser funcionalitzat posteriorment amb nanoparticules de pal·ladi i emprat en un procés catalític en cascada. Mecanismes de reacció han estat proposat per a cada procés catalític. L'efecte beneficiós a causa de la presència dels grups silanols en la superfície de suport també va ser analitzat. En el Capítol 5, la síntesi de catalitzadors híbrids multi-funcionals va ser descrita. Basant-se en els resultats obtinguts en el Capítol 4, s'ha preparat un catalitzador que presenti grups aminopropil- i nanopartícules de palladi. Les propietats estructurals i texturals han estat estudiades. A més, a través de la microscòpia electrònica de trans-missió, la distribució dimensional de les nanoparticulas ha estat estimada, resultant en una grandària mitjana equivalent a la dimensió dels canals mesoporosos del suport, MCM-41. El material ha estat emprat com a catalitzador multi-funcional.
[EN] The research work described in this Doctoral Thesis was developed within the frame of the MULTI2HYCAT European Project (grant agreement N. 720783) and it is focused on the synthesis and characterization of mono- and multi-functional hybrid catalysts featuring acid, base or redox active sites. Several research lines have been developed in parallel to design multiple hybrid catalysts for different catalytic processes, building upon the needs of the industrial partners. Due to the collaborative nature of the project, each academic partners mainly focused on one aspect of the whole process. Instituto de Tecnología Química (ITQ-CSIC), where this Thesis was developed, mostly focused on the design and synthesis of the hybrid catalysts. For that, part of the characterization results reported in Chapter 3 have been carried out at Università del Piemonte Orientale (IT), during a one month stay. Some of the catalytic results reported in Chapter 3 and Chapter 5 have been car-ried out by the University of Southampton (UK). In Chapter 3 the synthesis of two different heterogeneous hybrid catalysts carrying aryl-sulfonic moieties, in which the aromatic ring was either fluorinated or not, is re-ported. Two multi-step synthetic approaches were developed, involving the synthesis of the silyl-derivative precursor, template-free one-pot co-condensation (at low tem-perature and neutral pH) and tethering reaction. A multi-technique approach was im-plemented to characterize the hybrid catalysts. Textural properties, thermal stability and chemical makeup of the materials were studied. Moreover, probe molecules were adsorbed onto the hybrids and the interaction were studied with multi-nuclear NMR and FTIR spectroscopies. The catalytic activity of the two hybrids showed superior performances for the fluoro-aryl-sulfonic acid, compared to the non-fluorinated mate-rial, in the acetal formation between benzaldehyde and ethylene glycol. Silanol-capped versions of the hybrids have also been prepared and their properties have been com-pared with those of hydrophilic hybrids, to study the effect of the polarity of the sur-face on the overall catalytic activity of the hybrids. In Chapter 4, the synthesis of hybrid mesoporous organocatalysts, obtained by graft-ing of commercial and custom-made silyl-derivatives onto MCM-41 supports, is re-ported. The hybrid catalysts were characterized and tested for different reactions in-volving C-C bond formation, such as Knoevenagel condensations and Michael addi-tion. Finally, the catalysts were tested in the condensation between furfural and methyl isobutyl ketone and the most performing catalyst was selected for the synthesis of a multi-functional hybrid. Reaction mechanisms have been proposed and the beneficial effect of the surface silanol groups on the catalytic activity was demonstrated. In Chapter 5, the synthesis of hybrid multi-functional catalysts is reported. Building upon the results reported in Chapter 4, a hybrid catalyst featuring aminopropyl moie-ties and palladium nanoparticles was developed. Structural and textural properties of the catalysts were accessed. Moreover, transmission electron microscopy showed a narrow nanoparticles distribution, centered a value equivalent to the size of the meso-porous channels of the support. The catalyst was tested in a tandem process involving the aldol condensation between furfural and methyl isobutyl ketone followed by hy-drogenation of the aldol adduct. The influence of several variables on the activity of the multi-functional catalyst was explored, with the scope of paving the way for more thorough studies to be carried out in flow regime. Lastly, proof-of-concept syntheses of multi-functional hybrid catalysts featuring base sites and supported metal complex are reported.
The research work described in this Doctoral Thesis was developed within the frame of the MULTI2HYCAT European Project (grant agreement N. 720783). I would like to thank la Caixa foundation for my PhD scholarship.
Erigoni, A. (2021). Organic-Inorganic Hybrid Catalysts for Chemical Processes of Industrial Interest [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/165238
TESIS

Lors de leur stockage ou de leur exposition, les objets du patrimoine sont soumis à des processus physico-chimiques d’altération liés à leur environnement et en particulier à l’action de polluants primaires (e.g. dioxyde de soufre, oxydes d’azote), secondaires (ozone) ou de composés organiques volatils (COVs). Il a été démontré que ces gaz/vapeurs se comportent comme des agents d’hydrolyse et d’oxydation. L’acide acétique fait partie des COVs ayant un impact considérable et reconnu dans la conservation des objets du patrimoine en particulier des films photographiques. En vue de lutter contre ses effets délétères, ce projet de thèse s’est focalisé sur la conception de nouveaux matériaux poreux hybrides multifonctionnels appelés « Metal-Organic Frameworks » (MOFs) pour la capture sélective de l’acide acétique en présence d’humidité (40% humidité relative) et à température ambiante. Les remarquables propriétés d’adsorption (sensibilité, sélectivité et capacité) et la grande versatilité des MOFs (balance hydrophile/hydrophobe, taille/forme des pores,…) ont été utilisés pour préconcentrer de façon sélective l’acide acétique en milieu humide. Les matériaux les plus performants ont ensuite été préparés sous forme de nanoparticules pour l’élaboration de films minces de qualité optique afin d’en étudier les propriétés d’adsorption et de co-adsorption (acide acétique/eau) par ellipsométrie. L’incorporation de nanoparticules métalliques plasmoniques a ensuite été effectuée afin de concevoir un capteur colorimétrique. L’objectif final de ce travail est de concevoir un nouveau type d’adsorbant caractérisé par une capacité et une sélectivité d’adsorption élevée et dont on pourrait aisément déterminer le niveau de saturation en acide acétique afin d’anticiper son remplacement et ainsi assurer la préservation des objets stockés et exposés dans les musées
During their storage or their exhibition, the cultural heritage objects undergo physicochemical alteration processes related to their environment and in particular to the action of primary (e.g. sulfur dioxide, nitric oxides), secondary (ozone) pollutants or Volatile Organic Compounds (VOCs). It has been demonstrated that these gases/vapors are involved in hydrolysis and oxidation reactions. Among the most common VOCs encountered in museums, Acetic acid has a significant and recognized role in the deterioration of cultural heritage objects such as photographic films. In order to face this issue, this Ph.D. thesis focused on the design of new porous multifunctional hybrid materials denoted « Metal-Organic Frameworks » (MOFs) for the selective capture of acetic acid in the presence of moisture (40% relative humidity) and at room temperature. The remarkable adsorption properties (sensitivity, selectivity and capacity) and the great versatility of MOFs (hydrophicity/hydrophobicity balance, size/shape of pores,…) were used to preconcentrate selectively the acetic acid in humid conditions. The most performing materials were then prepared as nanoparticles and then used for the elaboration of high optical quality thin films in order to study the coadsorption (acetic acid/water) properties of MOFs by ellipsometry. The incorporation of plasmonic metal nanoparticles was then carried out in order to design a colorimetric sensor. The final objective is to devise a novel type of adsorbent that integrates a high VOC adsorption capacity and selectivity under humid conditions and an easy on-line monitoring of their saturation capacityin order to anticipate its replacement and therefore ensure the preservation of the stored and exhibited objects in museums

Nanotechnology as a field has the potential to answer some of the major challenges that mankind faces in regards to environmental sustainability, energy generation and health care. Though, solutions to these concerns can not necessarily rely on our current knowhow. Instead, it is reasonable to expect that humanity must adapt and learn to develop new materials and methods to overcome the adversities that we are facing. This master thesis has involved developing novel materials, serving as a small step in the continuous march towards a bright future where this is possible. More specifically, this work sought to combine mesoporous magnesium carbonate with various metal-organic frameworks to utilize the beneficial aspects from each of these constituents. The ambition was that these could be joined to render combined micro-/mesoporous core-shell structures, with high surface areas and many active sites whilst maintaining a good permeability. Numerous different synthesis routes were developed and explored in the pursuit of viable routes to design novel materials with potential future applications within for instance drug delivery, water harvesting from air and gas adsorption. Coreshell structures of the hydrophilic mesoporous magnesium carbonate covered with the hydrophobic zeolitic imidazole framework ZIF-8 was successfully synthesized for the first time, and practical studies demonstrated a dramatically enhanced water stability, which is perceived to have an impact on further research on these materials. ZIF-67 was also combined with mesoporous magnesium carbonate in a similar manner. Further, Mg-MOF-74 was grown directly from mesoporous magnesium carbonate, where the latter acted as a partially self-sacrificing template, with the aim of rendering a porous hierarchical structure with contributions from the micro- and mesoporous ranges. The outcomes of all these syntheses were characterized using several analyzing methods such as scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy and nitrogen sorption analysis.

The separation of industrially important gases into pure supplies that can be used for many practical applications is based mainly on energy intensive methods such as the cryogenic distillation which is costly and energy intensive. Therefore other routes have been introduced to industrial separation of gases such as the selective adsorption using porous solid materials. Zeolites and activated carbon are the most widely used recyclable energy-efficient porous solid materials for industrial gas separations, however the low uptake and selectivity hurdles their commercialization in some separation applications. Metal organic frameworks (MOFs) have been extensively studied as solid porous materials in term of gas separations nevertheless the future of MOFs for practical gas separations is considered to be vague and stringent due to their low stability, low capacity and selectivity especially at low partial pressures of the adsorbed gas, the competitive adsorption of the contaminants such as H2O, NOX and SOX, high cost of the organic ligands, besides the challenges of the formulation of MOFs which is very important in the MOFs marketing. In this context we present new porous materials based on inorganic linkers as well as the organic molecules, Organic-Inorganic Hybrid Materials, which were found to conquer the current challenges for the exploitation of MOFs in practical gas separation such as separation of trace and low CO2 concentrations and Xe separation from Xe/Kr mixtures. The work presented herein encompasses the development of novel 48.67 topology metal organic material (MOM) platform of formula [M(bp)2(M'O4)] (M= Co or Ni; bpe= bipyridine-type linkers; M'= W, Mo or Cr) that have been assigned RCSR code mmo based upon pillaring of [M(bp)2] square grids by angular WO42-, MoO42- or CrO42- pillars. Such pillars are unexplored in MOMs. They represent ideal platforms to test the effect of pore size and chemistry upon gas sorption behavior since they are readily fine-tuned and can be varied at their 3-positions (metal, organic linker and the inorganic pillar) without changing the overall structure. Such an approach allows for systematic control of pore size to optimize interactions between the framework and the adsorbent in order to enhance selectivity and/or gas uptake. Interestingly, these nets showed a high chemical stability in air, water, boiling water and in a wide range of pH which is certainly a desirable property in industry and commercialization of MOMs. [Ni(bpe)2(MoO4)] (bpe= 1,2-bis(4-pyridyl) ethane), MOOFOUR-1-Ni, and its chromate analog, CROFOUR-1-Ni, exhibit remarkable CO2 affinity and selectivity, especially at low loading. This behavior can be attributed to exceptionally high isosteric heats of adsorption (Qst) of CO2 in MOOFOUR-1-Ni and CROFOUR-1-Ni of ~56 and ~50 kJ/mol, respectively, at zero loading. These results were validated by modeling which indicate that the electrostatics of such inorganic anions towards CO2 affords favourable attractions to CO2 that are comparable to the effect of unsaturated metal centres. The use of WO42- instead of CrO42- or MoO42- as an angular pillar in mmo topology nets has afforded two isostructural porous nets of formula [M(bpe)2WO4] (M = Co or Ni, bpe=1,2-(4-pyridyl)ethene). The Ni variant, WOFOUR-1-Ni, is highly selective towards CO2 thanks to its exceptionally high isosteric heat of adsorption (Qst) of -65.5 kJ/mol at zero loading. The fine-tunability and the inherent modularity of this platform allow us exquisite design and control over the pore chemistry through the incorporation of different functionalities inside the channels of the networks which was then demonstrated as valuable strategy in terms of carbon dioxide capture at condition relevant to the direct CO2 capture from air. The exploitation of 4,4'-azopyridine in the design and synthesis of CROFOUR-2-Ni, an isostructure of CROFOUR-1-Ni, affords a paradigm shift in the CO2 adsorption properties as exemplified by the enhanced CO2 isosteric heat of adsorption at moderate and high loading in CROFOUR-2-Ni and the superior CO2 selectivity even for trace and low CO2 concentration. The two isostructures, CROFOUR-1-Ni and CROFOUR-2-Ni have been also investigated in term of Xe adsorption and separation from Xe/Kr mixtures. The two structures were found to exhibit the remarkable Xe affinity and selectivity which, together with high stability, good recyclability, low regeneration energy and low cost of the two materials could not only diminish the cost of the Xe and Kr production but also can potentially afford a high purity of the separated gases.

The germylenes, germanium(II) 2-(oxidomethyl)phenolate (1), germanium(II) 4-methyl-2-(oxidomethyl)phenolate (2) and germanium(II) 4-bromo-2-(oxidomethyl)phenolate (3) were synthesized and their thermally induced twin polymerization to give organic–inorganic hybrid materials was studied. The compounds 1–3 form oligomers including dimers, trimers and tetramers as a result of intermolecular coordination of the benzylic oxygen atom to germanium. The structural motifs were studied by single crystal X-ray diffraction analysis and DFT-D calculations. Thermally induced twin polymerization of these germylenes gave hybrid materials based on germanium-containing phenolic resins. Carbonization of these resins under reductive conditions resulted in porous materials that are composed of germanium and carbon (Ge@C materials), while oxidation with air provided non-porous germanium dioxide. The porous Ge@C materials were tested as potential anode materials for rechargeable Li-ion batteries. Reversible capacities of 540 mA h g−1 were obtained at a current density of 346 mA g−1 without apparent fading for 100 cycles, which demonstrates that germanium is well accessible in the hybrid material
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La recherche de nouveaux matériaux en tant que photocatalyseurs en lumière visible pour la dépollution de l’environnement (eaux, atmosphères) est un domaine de recherche très actif et suscite l’intérêt d’une large communauté scientifique en Physique, Chimie et Sciences des matériaux. Des recherches exhaustives sont actuellement menées pour améliorer l’efficacité photocatalytique de certaines classes de matériaux photoactifs connus, et pour développer la synthèse de nouveaux matériaux fonctionnels. Dans ce contexte, les semiconducteurs oxydes photoactifs à base de vanadates de bismuth (BiVO4) possédant une bande électronique au milieu du spectre visible, offrent une sérieuse alternative aux photocatalyseurs classiques efficaces (TiO2, ZnO) dont la photo-excitation requiert uniquement la fraction UV du spectre solaire. Le travail effectué dans le cadre de cette thèse est donc dédié aux matériaux à base BiVO4 sous forme d’architectures mésoporeuses ou d’assemblages hybrides associant des groupes organiques à transfert de charges.Deux contributions majeures ont été développées dont la première portant sur la réalisation expérimentale d’architectures mésoporeuses inédites, fonctionnalisées par des groupes organiques sensibilisateurs et l’étude de leurs propriétés électroniques et optiques en vue d’optimiser leurs efficacités photocatalytiques. La deuxième partie porte sur des simulations numériques de nanostructures hybrides par des approches exploitant la méthode DFT, ab-initio ou des modèles de chimie quantique. Des systèmes modèles ont été construits associant des nanoclusters (NC) et des groupes organiques (GO). Les propriétés électroniques et optiques ainsi que les caractéristiques structurelles et vibrationnelles des systèmes (NC-GO) ont été déterminées et confrontées aux données expérimentales. Les phénomènes de transfert de charges impliqués entre les groupes organiques et la structure inorganique ont été caractérisés ainsi que leur rôle dans l’efficacité des réponses photo-catalytiques des systèmes hybrides
The search for new materials as photocatalysts invisible light for the depollution of the environment (waters, atmospheres) is a very active field of research and attracts the interest of a large scientific community in Physics, Chemistry and Materials Science. Recent research developpements are conducted to improve the photocatalytic efficiency of certain classes of known photoactive materials, and to develop the synthesis of new functional materials. In this context, photoactive oxide semiconductors based on bismuth vanadate (BiVO4) having an electronic band in the middle of the visible spectrum, offer a serious alternative to efficient conventional photocatalysts (TiO2, ZnO) whose photo-excitation requires only the UV fraction of the solar spectrum.The work done in this thesis is therefore dedicated toBiVO4-based materials in the form of mesoporous architectures or hybrid assemblies associating organic groups with charge transfer processes. Two major contributions have been developed, one of which is the experimental realization of novel mesoporous architectures, functionalized by sensitizing organic groups and the study of their electronic and optical properties in order to optimize their photocatalytic efficiencies. The second part deals with numerical simulations of hybrid nanostructures using approaches as the DFT method, ab-initio or quantum chemistry codes. Model systems have been constructed associating BiVO4nanoclusters (NC) and organic groups (GO). The electronic and optical properties as well as the structural and vibrational characteristics of the systems (NC-GO) were determined and compared with the experimental data. The charge transfer phenomena involved between the organic groups and the inorganic structure were characterized as well as their role in the efficiency of photo-catalytic responses of hybrid systems

Hybrid materials consisting of three different components were synthesized by the polymerization of one heterotrifunctional monomer in just one reaction step using, at the most, one catalyst. The polymerization of 2-furfuyloxy-2-methyl-4H-1,3,2-benzodioxasiline leading to a hybrid material consisting of phenolic resin, poly(furfuryl alcohol), and polymethylsilsesquioxane is, to the best of our knowledge, the first polymerization of this kind. The influence of different catalysts on the polymerization behavior and thus on the structure of the hybrid material was investigated. In accordance with the term “twin polymerization”, which is used for the polymerization of one monomer yielding two separate polymers, this type of polymerization could be called “triple polymerization”. The term “multiple polymerization” is introduced as a general term for the underlying concept of the synthesis of multiple polymers starting from one monomer in one process step
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Es wurden verschiedene NMR-spektrokopische Messungen an flexiblen und chiralen MOFs durchgeführt. Zur Untersuchung der Porensysteme kamen 129Xe-NMR und 13C-NMR an adsorbiertem CO2 zum Einsatz, während die MOF-Gitter und ihre Wechselwirkungen mit adsorbierten Gastmolekülen mittels 13C- und 1H-MAS-NMR-Spektroskopie studiert wurden. Während DUT-8(Ni) Flexibilität zeigt, weist DUT-8(Cu) ein starres Gitter auf. Die Flexibilität der sogenannten Solid-Solutions hängt in ausgeprägter Weise vom Verhältnis der funktionalisierten bdc-Linker 2,5-bme-bdc und db-bdc ab. Dieses Verhältnis hat zudem einen großen Einfluss auf die Orientierung der adsorbierten CO2-Moleküle. Es wurde erstmals eine Methode vorgestellt, die den Festkörper-NMR-spektroskopischen Nachweis chiraler Seitengruppen in chiralen MOFs erlaubt, wie anhand des chiral modifizierten UMCM-1 (ChirUMCM-1) demonstriert wurde. Die Chiralität kann einen NMR-spektroskopisch messbaren Einfluss auf die intrinsische Dynamik des MOF-Gitters ausüben, wie am chiral modifizierten DUT-32 deutlich wurde, dessen chirale Seitengruppe selektiv 15N- und 13C-isotopenmarkiert wurde.

Les matériaux hybrides de type MOFs sont des solides poreux dans lesquels des centres métalliques sont reliés entre eux par des ligands organiques. Il est possible, non seulement de faire varier la taille et la géométrie de leurs porosités, mais aussi de moduler leurs compositions chimiques en modifiant à la fois la nature de la brique inorganique et des groupements sur le ligand organique. Cette nouvelle famille de matériaux a fait l'objet d'une attention particulière ces dernières années pour des applications potentielles dans différents domaines à fort intérêt socio-économique comme le captage ou la séparation de gaz ou bien encore la catalyse. Au-delà d'une stabilité chimique et thermique, ces matériaux doivent être aussi suffisamment résistants mécaniquement pour s'adapter au mieux aux contraintes de l'application visée (mise en forme de l'échantillon, conditions opératoires….). Il est donc impératif de connaître les propriétés mécaniques de ces nouveaux matériaux, sujet qui n'a fait l'objet à ce jour que de très peu d'études. L'objectif de ce travail est donc de mettre en œuvre des mesures de diffraction des rayons X et neutrons sur grands instruments afin de caractériser dans un premier temps le comportement structural du matériau flexible MIL-53 (MIL pour Matériaux de l'Institut Lavoisier) sous l'application d'une pression mécanique modérée (P~1 GPa) en fonction de la nature du métal (Al,Cr) et de la fonction greffée sur le ligand organique (-H, -Cl, -CH3). Ces données expérimentales sont ensuite discutées à partir de résultats issus de la simulation moléculaire. L'étape suivante consiste à étudier l'effet du confinement de molécules de solvants dans les pores de ce solide sur la transition structurale du réseau hôte. Enfin, deux familles de MOFs rigides, la MIL-125(Ti) et l'UiO-66(Zr) (UiO pour Unversité d'Oslo) sont considérées afin de caractériser non seulement leur domaine de stabilité mécanique en pression (Pmax~ 5 GPa) mais aussi leur compressibilité. Les résultats ainsi obtenus sont comparés aux performances mécaniques des meilleurs MOFs
Metal Organic Framework (MOF) materials have been the focus of intense research activities over the past 10 years, with the emergence of a wide range of novel architectures, constructed from inorganic clusters linked by organic moieties. In order to maintain their useful functionalities and high performances in the different fields explored so far (gas storage/separation, catalysis, sensors and many others), besides high chemical and thermal stabilities, MOFs must be also stable enough to resist to different mechanical constraints in both processing and applications. Indeed, there is nowadays a growing interest to characterize the mechanical behaviours of this class of materials under moderate and high applied pressure. This work first aimed to probe the pressure dependence of the structural behaviour of the highly flexible MIL-53 system [MIL stands for Materials of Institut Lavoisier] as a function of the nature of (i) the metal center (Al,Cr) and (ii) the functional group grafted on the organic linker (-H,-Cl,-CH3) using a combination of high-pressure x-ray/neutron diffraction and molecular simulations. The same methodology was further applied to probe how the presence of guest molecules affects the structural transition of this class of hybrid porous solids. Finally, the mechanical stability and the compressibility of two families of rigid MOFs, the MIL-125(Ti) and the UiO-66(Zr) [UiO stands for University of Oslo] up to high pressure (P~5 GPa) have been investigated and their properties in terms of bulk modulus were compared with the most resilient MOFs reported so far

Ce travail a concerné la synthèse hydro-solvothermale et la caractérisation de nouveaux fluorures hybrides à porosité variable, dans l’objectif à terme de tester ces matériaux poreux en stockage ou purification de gaz. En première partie, l’aminotétrazole a été utilisé comme ligand organique et a permis de mettre en évidence douze nouveaux fluorures hybrides, dont six sont de type MOF. Plusieurs paramètres de synthèse ont été identifiés comme cruciaux dans la condensation d'édifices ouverts. C’est, en particulier, la température, la composition du milieu ainsi que la nature des cations métalliques (Zn2+/Fe3+, Fe2+/Fe3+ et Zn2+ seul) et du solvant. Les porosités estimées de ces MOF atteignent 25% en volume bien que la taille de l’aminotétrazole soit réduite. En seconde partie, des ligands plus étendus à noyaux tétrazoliques multiples ont été choisis afin de parvenir à augmenter la dimension des cavités des MOFs. Ces molécules, non commercialisées, ont été synthétisées dans un premier temps puis impliquées dans l’élaboration de nouveaux hybrides. Alors que la molécule H3btt à 3 noyaux tétrazole n’a pas abouti à des résultats, H2bdt a conduit à de nouvelles architectures fluorées en présence de Zn et/ou Fe. Deux d’entre elles, [Hdma]∙(FeIIF(bdt)) et FeIIF(Hbdt), présentent des porosités remarquables de 40 et 60% qui s’approchent de celles des matériaux de référence
This work focuses on the hydro-solvothermal synthesis and the characterization of new hybrid fluorides with tunable porosity, with the aim of testing new porous materials for gas storage and purification. In the first part, the aminotetrazole was used as organic linker and twelve new hybrid fluorides were evidenced, six phases belong to MOFs class. Several parameters were identified as crucial for the condensation of open frameworks, in particular, the temperature, the medium composition as well as the nature of metallic cations (Zn2+/Fe3+, Fe2+/Fe3+ or only Zn2+) and of the solvent. The porosity of these MOFs reaches 25% of volume, in spite of the small size of the aminotetrazole molecule. In the second part, polytetrazoles linkers with extended size were chosen, in order to increase the size of MOFs cavities. Non-commercial molecules were prepared and applied to the elaboration of new hybrids. While H3btt with 3 tetrazole cycles did not provide any expected result, H2bdt led to new fluorinated architectures in the presence of Zn and/or Fe. Two phases, [Hdma]∙(FeIIF(bdt)) and FeIIF(Hbdt), exhibit remarkable porosities of 40 and 60%, values

Four molecular germanates based on salicyl alcoholates, bis(dimethylammonium) tris[2-(oxidomethyl)phenolate(2-)]germanate (1), bis(dimethylammonium) tris[4-methyl-2-(oxidomethyl)phenolate(2-)]germanate (2), bis(dimethylammonium) tris[4-bromo-2-(oxidomethyl)phenolate(2-)]germanate (3) and dimethylammonium bis[2-tert-butyl-4-methyl-6-(oxidomethyl)phenolate(2-)][2-tert-butyl-4-methyl-6-(hydroxymethyl)phenolate(1-)]germanate (4), were synthesized and characterized including single crystal X-ray diffraction analysis. In the solid state, compounds 1 and 2 exhibit one-dimensional hydrogen bonded networks, whereas compound 4 forms separate ion pairs, which are connected by hydrogen bonds between the dimethylammonium and the germanate moieties. The potential of these compounds for thermally induced twin polymerization (TP) was studied. Germanate 1 was converted by TP to give a hybrid material (HM-1) composed of phenolic resin and germanium dioxide. Subsequent reduction with hydrogen provided a microporous composite containing crystalline germanium and carbon (Ge@C – C-1, germanium content ∼20%). Studies on C-1 as an anode material for Li-ion batteries revealed reversible capacities of ∼370 mA h gGe@C−1 at a current density up to 1384 mA g−1 without apparent fading for 500 cycles
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En 2004, le carbone, la base de toute vie connue sur Terre, a marqué les esprits une fois de plus: Les scientifiques de l’Université de Manchester au Royaume Uni ont pu extraire une matière carbonée complètement nouvelle, le graphène à partir d’un morceau de graphite comme celui qui compose les crayons. À l’aide d’un ruban adhésif, ils ont obtenu une paillette de carbone de l’épaisseur d’un atome seulement, à une époque où beaucoup pensaient qu’un matériaux cristallin aussi fin ne pouvait pas être stable. Le graphène parfait est une couche monoatomique composée d’atomes de carbone hybridés sp2, arrangés en structure alvéolaire; sa structure chimique particulière lui donne des propriétés physiques et chimique remarquable. Le graphène est devenu rapidement la matière carbonée la plus intensivement étudiée parmi celles «possiblement révolutionnaires», avec ses applications potentielles s’étendant de la microélectronique aux composites, des énergies renouvelables à la médecine. En 2010, Geim et Novoselov ont été récompensés par le prix Nobel de physique pour leurs «expériences révolutionnaires sur les matériaux bi-dimensionnels en graphène» qui a ouvert une nouvelle ère dans la science des matières carbonées.La chimie non-covalente du graphène est exploitée et étudiée dans cette thèse dans le but de concevoir, produire, transformer et caractériser les nouveaux matériaux hybrides graphène-organique. L’étendue de ce travail couvre les aspects mécanistiques de l’exfoliation en phase liquide du graphène avec des colorants, les aspects fondamentaux des interactions entre le graphène et le chromophore, en phase liquide et solide, ainsi que l’élaboration de suspensions hybrides de graphène dans le but d‘applications en électronique organique et dans les matériaux composites polymères fonctionnels
In 2004, carbon, the basis of all known life on earth, has surprised once again: Researchers from University of Manchester, UK, extracted a completely new carbon material, graphene, from a piece of graphite such as is found in pencils. Using adhesive tape, they obtained a flake of carbon with a thickness of just one single atom, at a time when many believed it impossible for such thin crystalline materials to be stable. Pristine graphene is a mono-atomic sheet of, sp2 hybridized carbon atoms arranged in a honeycomb network; this particular chemical structure gives rise to its outstanding physical and chemical properties. Graphene rapidly became the most intensively studied among the ‘possibly revolutionary’carbon materials, with its potential applications reaching from microelectronics to composites, from renewable energy to medicine. In 2010, Geim and Novoselov were honored with the Nobel Prize in Physics for their “ground breaking experiments regarding the two-dimensional material graphene” that started a new era in the science of carbon materials.In this thesis we exploit and study the non-covalent chemistry of graphene to design, produce, process and characterize novel graphene organic hybrid materials. The scope of this work covers mechanistic aspects of graphene liquid phase exfoliation with dyes, fundamental aspects of graphene chromophore interactions in liquid and solid phase and the formulation of graphene hybrid suspensions towards application in organic electronics and functional polymer composite materials

Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2009.
Title from electronic title page (viewed Jun. 26, 2009). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Chemistry." Discipline: Chemistry; Department/School: Chemistry.

The goal of the work presented in this thesis, was to develop inorganic material systems synthesized via organic precursors and to pattern them using different lithographic techniques. The materials investigated were the ferromagnetic Ni metal and the mesoporous TiO2 and Nb2O5, which have applications in dye sensitized solar cells. The first part of the thesis presents an overview of pattern formation in organic and inorganic materials and the working principles of dye sensitized solar cells. Next the theoretical background of block-copolymer and block-copolymer structure directing hybrid materials are described. Fundamental knowledge of magnetism and ferromagnetism are also presented. The techniques used to characterize the material and the fabricated devices are detailed. For example, the samples were characterized using magnetic force microscopy (MFM) and scanning electron microscopy (SEM), while the materials were characterized by BET. The fabrication of Ni metal films using sol-gel process is then discussed. The Ni metal films were patterned with sub-10 nm wide lines via direct-writing electron beam lithography, and their electrical resistivity was investigated. The in uence of mesoporous TiO2 obtained using a block-copolymer, which acted as a structure-directing agent for the metal oxide, is then presented. This material was incorporated into solid state dye sensitized solar cells. The development of a mesoporous material fabrication protocol, which has significantly in uenced solar cell efficiency, is discussed. Finally the general ideas and some preliminary results on a mesoporous Nb2O5 material and its application in dye sensitized solar cells are presented.

Two types of coating materials were prepared by a sol-gel process and classified into two systems. In system I, four different types of the optically transparent organic-inorganic hybrid coating materials produced by The Welding Institute (TWI) using a patent method called Vitresyn, identical in terms of the precursors, but different in terms of their relative proportions, were examined. The precursors used for system I were tetraethoxysilane (TEOS), 3-(trimethoxysilyl)propyl methacrylate (MPTMA) and an aliphatic urethane acrylate. The coating materials were deposited on aluminium, brass and polycarbonate substrates by a flow coating method, and cured under a UV lamp for various times from 2 minutes to 40 minutes. In system II, MPTMA, Methyltrimethoxysilane (MTMS) and trimethoxysilypropyl acrylate (PATMS) were used as precursors. No urethane acrylate was used in this system. TEOS was used in system I as the primary inorganic precursor and urethane acrylate was used as the source of organic component. MPTMA was used as both a secondary inorganic source and a coupling agent between the organic and inorganic phases. To ascertain the interaction relationships between organic and inorganic phases in the hybrid materials, Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR) were used. It was found that a siloxane (Si­O-Si) network is a backbone of the hybrid materials and that the network increases with increasing inorganic content in the hybrid materials. These organic-inorganic hybrid materials were mainly cross-linked by T³, Q³ and Q⁴ species. It was also found that UV curing leads to accelerated condensation reaction through the opening of C=C bonds in MPTMA and urethane acrylate. Microstructures in the coatings and interfaces between the coatings and the substrates were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The coating thickness is dependent on the relative amount of organic resin added to the hybrid materials. The coating thickness increases as more organic resin (urethane acrylate) is used. Neither silica domains nor pores were observed in the coatings. It was concluded that the hybrid coating materials are a single featureless amorphous phase regardless of the organic/inorganic ratios. Scratch testing was used to study the scratch resistance of the hybrid materials and the interfacial strength between the coatings and the substrates. A micro-indentation adhesion test using focused ion beam (FIB) technologies was also used for investigating interfacial strength. The results showed that scratch resistance increases with an increase in the relative amount of organic resin added.

Polyoxometalates are the polyoxoanions of the early transition metals, especially tungsten, molybdenum and vanadium. Although they were first described in the 19th century, their development was slow until modern experimental techniques enabled a greater understanding of their structures and properties. In the last 40 years a large variety of shapes, sizes and compositions have been investigated; functionalisation via covalent grafting of organic groups onto the polyoxometalate clusters is less investigated and provides a method of fine tuning the properties of these materials towards desired applications. Polyoxotungstates (polyoxometalates with tungsten as the metal) are investigated here, those with the Keggin structure being of interest due to the relatively easy formation of lacunary anions which have a highly nucleophilic surface and can react with electrophilic groups to add functionality to the cluster. Organophosphonyl and organosilyl derivatives are prepared with formulae (NR¹₄)₃Hn[XW₁₀O₃₆(R²PO)₂], (NBu₄)₃[XW₉O₃₄(R³SiO)₃(R³Si)], (NBu₄)₃Hn[XW₉O₃₄(tBuSiOH)₃], (NBu₄)₃Hn[XW₉O₃₄(tBuSiO)₃(SiR⁴)], (NBu₄)₃Hn[XW₉O₃₄(R²PO)₂] or (NBu₄)₃Na[SiW₉O₃₄(R²PO)₃] (X = Si or P; R¹ = Bu or Et; R² = Et, H₂C=CH, H₂C=CHCH₂, H₂C=CHC₆H₄, HOOC(CH₂)m (m = 1 or 2) or H₃CCOC₆H₄; R³ = H₂C=CH or H₂C=CHCH₂; R⁴ = R³ or (CH₂)₃Br; n=0 or 1). The structures are confirmed and investigated using multinuclear NMR (¹H, ³¹P and ²⁹Si), IR, MS, EA, single crystal X-ray diffraction and Cyclic Voltammography. The derivatised polyoxotungstate clusters have the potential to take part in further reactions using the organic functionalities to create inorganic-organic hybrid materials which retain the electrochemical properties of the polyoxotungstate units. Examples include the polymerisation of carbon double bonds and condensation reactions of carboxylic acids and amines; both are investigated here. Radical polymerisation is successful in creating polymeric materials, either through single reaction of the polyoxotungstate cluster or a co-polymerisation reaction with a second co-monomer. Reaction with amines did not proceed as expected, instead one of the RPO groups was removed from the cluster, producing a new set of singly derivatised clusters, [SiW₁₀O₃₆(R²PO)]⁶⁻ from [SiW₁₀O₃₆(R²PO)₂]⁴⁻. These create potential for a product with asymmetrically functionised polyoxotungstates containing a mixture of R groups [SiW₁₀O₃₆(R²PO)(R²bPO)]⁴⁻, thus providing greater control over the organic functionality on the cluster and increasing the number of potential derivatives available.

The prepaparation of amorphous, homogeneous blends of zwitterionic polymers and transition metal salts was investigated. Homogeneous miscibility was achieved in many cases up to equimolar amounts of salt, depending on the anion and cation chosen. Various analytical techniques point to a solid state solution of the inorganic ions in the polymer matrix.

This thesis describes the utilisation of a new, facile route for rapid ligand synthesis for the design, synthesis and characterisation of metal-organic frameworks (MOFs), and the subsequent refinement of ligand synthesis to discover a 2-step green alternative synthetic route to an analogous ligand for use in the same. From these ligands, two series of MOFs are detailed; a Cu(II) series with simulated isotherms showing promising CH4 and CO2 high pressure uptake, and two Zr(IV) MOFs with enhanced stability and their measured high pressure isotherms. Chapter 1 introduces the need for highly functional materials to answer the needs of current energy production crises; with the production of CO2 from fossil fuels predicted to continue dangerously damaging the environment for decades to come, while the fossil fuel energy sources themselves run out, alternatives are clearly needed to continue powering society. MOFs are introduced as potential materials which can fulfil both of these needs. Chapter 2 describes the synthesis of the H4LX series, which utilise the Suzuki-Miyaura cross-coupling reaction to generate a large quantity of a versatile ligand pre-cursor (3,5-di(p-carbethoxy)benzene boronic acid), which is then used to generate a large number of ligands via a further Suzuki-Miyaura cross-coupling reaction with a dihalogenated core. A green synthetic route to an analogous ligand to the first in the series (H4L1P, which differs from H4L1 by the replacement of two phenyl rings with pyridyls) is then described, which reduces the synthetic steps by 66% (2 steps instead of 6), and the cost by 95% (£0.51/g instead of £11.68/g). Chapter 3 describes the design, synthesis, and characterisation of a series of Cu(II) metal-organic frameworks (MFM-191 to 198), and their respective simulated isotherms, which enable rapid identification of promising frameworks for materials which theoretically approach and even exceed the American Department of Energy’s (DoE’s) target value for CH4 working capacity, and also potentially provide an alternative to current proposals for CO2 storage and shipping. The discussion on these frameworks is split into two studies: Exploration of the effects of interpenetration and classes thereof on low and high pressure gas sorption (MFM-191,192 and 193), and analysis of attempts to fine tune the high pressure uptake of a series of non-interpenetrated isoreticular structures via extension and functionalisation of the central core of the ligand (MFM-193 to 198). The first group of frameworks demonstrates how interpenetration aids low pressure uptake, but hinders maximum high pressure uptake. MFM-191 (which exhibits 2-fold interpenetration, class IIa) displays an uptake of CH4 of 1.97 wt% at 1 bar and 21.40 wt% and 80 bar, 298 K and an uptake of CO2 of 2.88 mmol/g at 1 bar, and 16.69 mmol/g at 30 bar, 298 K; while MFM-193 (a non-interpenetrated MOF with the same topology) demonstrates a greater difference between uptakes, with uptakes for CH4 of 0.85 wt% at 1 bar and 47.06 wt% for 80 bar, 298 K, and uptakes for CO2 of 0.65 mmol/g at 1 bar and 40.82 mmol/g at 30 bar, 298 K. This larger difference is due to the decreased host-guest interactions at low loadings, and works in favour of a better working capacity for CH4 for the non-interpenetrated framework. Alteration of the class of interpenetration (from class IIa to class Ia) results in overall uptake behaviour which lies between the two, displaying an uptake for MFM-192 of CH4 of 2.11 at 1 bar, and 31.36 wt% at 80 bar, 298 K and an uptake of 2.89 2.89 mmol/g at 1 bar and 24.07 mmol/g at 30 bar for CO2 at 298 K. The non-interpenetrated series of MOFs (MFM-193 to 198), shows how upon functionalisation of the central core of ligand H4L1, the gas sorption properties are increases in accordance to the aromaticity of the ligand, with an increase in maximum volumetric uptake (at 80 bar, 298 K) of CH4 from 233.29 to 251.89 cm3/cm3 from MFM-193 (with H4L1, a ligand with a phenyl ring as the central core) to MFM-195 (synthesised from H4LAN, a ligand with an anthracene moiety as its central core). Surprisingly, the amine-functionalised MOF (MFM-196) displays the lowest uptake of both CH4 and CO2 at high pressure compared to the other functionalised MOFs (MFM-194 and MFM-195) Extension of the ligand core from one phenyl ring to biphenyl and pyrene based ligands affords MFM-197 and MFM-198, which in turn display the highest theoretical gravimetric CH4 working capacities 5-80 bar (48.51 wt% and 44.15 wt% at 298 K, respectively). Furthermore, working capacities calculated from the 273 K simulated isotherms for MFM-198 (the pyrene functionalised framework) show that this MOF is capable of exceeding the DoE target for gravimetric working capacity of 50 wt% (and nearing the volumetric target of 264 cm3 cm-3), by delivering 52.3 wt% and 256.9 cm3 cm-3 between 5-80 bar. However, upon attempts to activate these Cu(II) frameworks, none were stable enough to obtain a permanent porosity, even from ‘soft’ activation methods such as supercritical CO2; therefore, new frameworks were sought which would be designed to have enhanced stability. Chapter 4 describes the synthesis of two Zr(IV) MOFs, synthesised from H4L1 and H4L1P (MFM-421 and MFM-422) designed to display enhanced stability over the Cu(II) MOF series, and allow acquisition of experimentally gathered high pressure data. This is particularly interesting for the MOF synthesised from H4L1P, as the green, cost-effective synthesis conditions of the ligand are potentially valuable for industrial applications. Both MOFs display an increase in stability over the Cu(II) series, with a measureable BET of 3,300 m2/g for MFM-421 and 2,500 m2/g for MFM-422. The high pressure CH4 and CO2 capacities of both frameworks were measured, and, while they were lower than the simulated Cu(II) series, they were highly competitive compared to published MOFs. MFM-421 is shown to have the fourth highest CH4 gravimetric working capacity at 298 K (compared to a list of the highest experimentally recorded MOFs for methane working capacity), and MFM-422 the sixth, measuring values of 25.7 wt% and 22.8 wt%, compared to the three highest of 31.0 wt%, 35.0 wt% and 42.3 wt% for MOF-177, MOF-205 and Al-soc-MOF-1, respectively. Importantly, compared to HKUST-1 (the only framework amongst this list that is cheaper than H4L1P to buy/synthesise), both of these frameworks exhibit higher gravimetric working capacities (which for HKUST-1 is 16.3 wt% at 298 K). The analysis of CO2 high pressure isotherms for potential in storage and shipping shows that these MOFs exhibit an increase in storage capacity at 298 K, 30 bar over capacity of a tank at the same conditions of over 500% for MFM-421 (7,708 mol/m3 compared to 1,458 mol/m3) and over 650% for MFM-422 (9,605 mol/m3). While the highest of these values still stands at only 43% of the value of a tank at 26.5 bar and 263 K, the ability to store this much CO2 at ambient temperatures allows more flexibility in route and less energy intensive storage conditions. Chapter 5 summarises the CH4 and CO2 storage properties of these structures and draws overall conclusions from the work.

Die vorliegende Arbeit befasst sich mit der Synthese und Charakterisierung von unterschiedlichen nanostrukturierten Hybridmaterialien ausgehend von nur einem Monomer. Dabei wird ein neuartiges Monomer vorgestellt, welches in einem Prozessschritt ein Hybridmaterial bestehend aus drei Polymeren bilden kann. Dies erweitert das Konzept der Zwillingspolymerisation, bei der zwei Polymere aus einem Monomer erhalten werden. Aus diesem Grund wurde der Überbegriff „Mehrlingspolymerisation“ für die Synthese von zwei oder mehr Polymeren aus nur einem Monomer eingeführt. Ein weiterer Schwerpunkt lag auf der gezielten Beschichtung verschiedener Partikeloberflächen mit nanostrukturierten Hybridmaterialien mittels Zwillingspolymerisation. Dabei wird der Einfluss der Oberfläche auf die Polymerisation verschiedener Zwillingsmonomere untersucht. Durch Nachbehandlung sind daraus poröse Kompositmaterialien zugänglich. Je nach Beständigkeit der Substrate sind diese in den Nachbehandlungsschritten stabil oder werden entfernt und dienen nur als Template zur Strukturierung der porösen Materialien. Es wurden unterschiedliche poröse Kohlenstoffe und Kohlenstoffkompositmaterialien hergestellt und charakterisiert. Ausgewählte Materialien wurden mit Schwefel verschmolzen und in Lithium-Schwefel-Zellen untersucht (Kooperation Dr. S. Choudhury, Leibniz-Institut für neue Materialien Saarbrücken). Die Charakterisierung der Proben erfolgte unter anderem mithilfe der Festkörper-NMR-Spektroskopie, Elektronenmikroskopie, dynamischen Differenzkalorimetrie, Röntgenpulver-diffraktometrie, Infrarotspektroskopie, Raman-Spektroskopie, Thermogravimetrie und Stickstoffsorption.

Efterfrågan på bättre och mer hållbart material ökar. Mer effektivt material kommer att behövas för att möta den ökande, globala efterfrågan. Hybrida organiska-oorganiska material är en typ av material som har varit av stort intresse nyligen, och kan beskrivas som en typ av material som består av både organiska och oorganiska komponenter. Denna avhandling har fokuserat på hybrida organiska-oorganiska material inspirerade av den klassiska perovskitstrukturen ABX3, där komponent A är en organisk katjon, komponent B är en divalent metalkatjon och komponent X är en anjon. Hybrida organiska-oorganiska material som är utgår från den klassiska perovskitstrukturen kan ha olika funktionella egenskaper och en bred variation av tänkbara applikationer. Några exempel på dessa egenskaper och möjliga applikationer inkluderar god fotokonduktivitet för solceller, utmärkt emissionsegenskaper för ljusdioder och justerbara dielektriska egenskaper för elektroniska växlar och sensorer.  De fysiska egenskaperna av det hybrida organiska-oorganiska materialet beror på kristallstrukturen av materialet, som i sig bestäms av valet av komponenter. På grund av de många möjligheter av organiska och oorganiska komponenter så finns det möjlighet att syntetisera helt nya hybrida organiska-oorganiska föreningar som kan ha nya eller förbättrade fysiska egenskaper.  Nuvarande hybrida organiska-oorganiska material som utgår från perovskitstrukturen använder huvudsakligen bly som divalent metalkatjon, och det beror på att den ger den bästa funktionella effekten. Blys toxicitet är dock en stor nackdel för nuvarande blybaserade hybrid oorganiska material. Möjligheten att ersätta bly med en annan divalent metall har undersökts under detta projekt. I denna avhandling så har den organiska katjonen cyclohexylammonium (CHA) varit i fokus som den organiska komponenten. Målet med detta examensarbete var att designa, syntetisera och karakterisera nytt hybrid organisk-oorganiskt material. De hybrida organiska-oorganiska föreningarna CHAZnBr3 och (CHA)2ZnBr4 syntetiserades för den första gången, så vitt författaren vet, och kommer vara i fokus i denna avhandling. De två nya hybrida organiska-oorganiska föreningarna blev strukturellt karakteriserade med X-ray Diffraction (XRD) och termiskt karakteriserade med Thermal Gravimetric Analysis (TGA) och Differential Scanning Calorimetry (DSC).  Den första föreningen, CHAZnBr3, kunde bestämmas att vara ortorombisk vid 298 K. Föreningen bestämdes vara termisk stabil upp till 490 K, och genomgår en fasövergång vid 445 K. Den andra föreningen, (CHA)2ZnBr4, kunde inte bestämmas strukturellt vid varken 100 K eller 298 K. Föreningen bestämdes vara termisk stabil upp till 490 K, och genomgår en fasövergång vid 230 K. Ytterligare karakterisering krävs för att bättre förstå egenskaperna hos dessa föreningar och deras möjliga användningsområden.
The demand for better and more sustainable material is increasing. More efficient materials will be needed to meet the growing global need. Hybrid organic-inorganic materials are one type of materials that have been of great interest recently, which can be described as a class of materials that mix organic and inorganic components. This thesis focused on hybrid organic-inorganic materials inspired by the classical perovskite crystal structure ABX3, where component A is an organic cation, component B is a divalent metal cation and component X is an anion. Hybrid organic-inorganic materials based on the classical perovskite structure may have various functional properties and may have a broad range of potential applications. Some examples of those properties as well as some and possible applications include good photoconductivity and power conversion efficiency for photovoltaic devices, excellent emission properties for light emitting diodes and tunable dielectric properties for electronic switches and sensors.  The physical properties of the hybrid organic-inorganic material are determined by the crystal structure of the material, which in turn will be decided by the choice of components. With the many possible choices for organic and inorganic components, there is an opportunity to synthesize completely new hybrid organic-inorganic compounds that may display new or superior physical properties. Current hybrid organic-inorganic materials based on the perovskite crystal structure mainly use lead as the divalent metal, since it currently gives the best performance. The toxicity of lead is a major drawback for current lead-based hybrid organic-inorganic materials. The possibility to replace lead with another divalent metal has been explored during this project. For this thesis, the organic cation cyclohexylammonium (CHA) has been of focus as the organic component. The aim of this thesis was to design, synthesize and characterize novel hybrid organic-inorganic compounds. The hybrid organic-inorganic compounds CHAZnBr3 and (CHA)2ZnBr4 were synthesized for the first time, to the best of our knowledge, and will be the focus of this thesis. The two new hybrid organic-inorganic compounds were structurally characterized by X-ray Diffraction (XRD) and thermally characterized by Thermal Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC).  The first compound, CHAZnBr3, could be determined to be orthorhombic at 298 K. The compound was found to be thermally stable up 490 K, and to undergo a phase transition at 445 K.  The second compound, (CHA)2ZnBr4, could not be fully structurally solved at either 100 K or 298 K. The compound was found to be thermally stable up to 490 K, and to undergo a phase transition at 230 K.  Further characterization will be needed to better understand the properties of these two compounds and their possible applications.

Solution-processable high refractive index materials are of immense interest for the production of optoelectronic devices, offering the prospect of high throughput, low cost and large area fabrication. In this thesis the optical characterisation of a relatively new type of optical material: the organic/inorganic molecular hybrid is presented. This molecular hybrid uses amorphous titanium oxide hydrates to cross-link polyvinyl alcohol (PVA) and in doing so enables the production of highly transparent thin film coatings with inorganic loadings approaching 100\%. The refractive index of the hybrid material is determined by probing Fabry-Perot oscillations in the transmittance spectra of thin films. This simultaneously demonstrates the high indices, low optical loss and excellent film quality possible for the hybrid. The refractive index is found to be tunable between 1.5 and 1.8 by adjusting the relative content of titanium. However, a simple thermal annealing process is shown to allow indices above 2, without compromising the transparency of the material. The index increase on thermal annealing is explained as the result of the large contraction that also occurs. The hybrid material is then used to fabricate several planar photonic structures. The first is a distributed Bragg reflector, in which the hybrid is deposited sequentially with a commercially available low index fluorinated polymer. The resulting structures have a high reflectance band that is controlled simply by the thicknesses of the high and low index layers. The DBRs demonstrate not only the excellent control of refractive index for the hybrid but also the ability to control layer thickness on the nanometre scale using dip coating. Infrared DBRs that are highly transparent in the visible are also fabricated as a possible application of the hybrid material system for heat management of glass clad buildings. Anti-reflective coatings are also demonstrated that remove 87\% of the reflectance from glass. This is achieved using a symmetrical bi-layer design, again dip cast from solution. Finally, all solution-processed optical microcavities are produced using the hybrid material. First, a simple defect is inserted into a DBR stack to induce a peak in transmittance inside the stop-band. This is then extended to include an emissive material: a perylene derivative, that is coupled to the cavity mode in order to alter its emission characteristics. This, to the best knowledge of the author, is the first demonstration of coupling in a solution-processed optical microcavity.

Ce travail a pour objectif l’étude de matériaux hybrides poreux de type Metal-Organic Frameworks (MOFs) et d’un cristal moléculaire en tant que conducteurs ioniques solides pour des applications dans le domaine de l’énergie et de l’environnement. Dans le premier cas, nous avons développé diverses stratégies pour optimiser et contrôler la teneur en sites acides de Lewis et en porteurs de charges de deux séries de MOFs afin de concevoir des matériaux aux propriétés de conduction protonique très prometteuses. A partir d’une approche basée sur la substitution progressive des ligands par des entités fonctionnalisées présentant des sources de protons acides, nous avons créé une série de MOFs, MIP-207-(SO3H-IPA)x-(BTC)1–x, dont la teneur en groupements sulfoniques, par l’intermédiaire du ligand SO3H-IPA, est contrôlée à façon. Le meilleur matériau qui combine stabilité structurale et conduction protonique élevée présente des performances sous humidité parmi les plus intéressantes au sein de la famille des MOFs conducteurs protoniques (e.g., σ = 2.6 × 10–2 S cm–1 à 363 K/95% d’humidité relative (RH)). Selon une autre approche, nous avons étudié un MOF mésoporeux connu (MIL-101(Cr)-SO3H) dont les parois des pores sont tapissées de sites protoniques et qui contient dans ses pores un liquide ionique, le chlorure chlorure de 1-Ethyl-3-methylimidazolium (EMIMCl) capable d’assurer le transfert de proton. L’encapsulation du liquide ionique, caractérisée par une série d’outils expérimentaux (sorption de diazote, DRX sur poudre, TGA/MS, DSC et analyse élémentaire), s’avère particulièrement efficace pour exalter les propriétés de conduction protonique des composites à la fois à l’état anhydre (σ473 K = 1.5 × 10-3 S cm-1) mais également à l’état hydraté (σ(343 K/60%-80%RH) ≥ 0.10 S cm-1). Enfin, ce travail a été étendu à une autre famille de solides poreux, à travers l’étude des propriétés de conduction ionique d’un cristal moléculaire à base de zirconium (Zr-3) qui contient des paires ioniques KCl. Nous avons démontré que ZF-3 transite d’un comportement isolant à l’état anhydre (σ = 5.1 x 10-10 S cm-1 à 363 K/0% RH) vers un comportement super-conducteur ionique en présence d’eau (σ = 5.2 x 10-2 S cm-1 à 363 K/95 % RH), suite à l’augmentation de la dynamique de ions Cl- sous hydratation. Par ailleurs, des simulations moléculaires ont permis de décrire les mécanismes microscopiques à l’origine des propriétés de conduction des matériaux étudiés. Ces avancées devraient permettre de développer dans le futur de nouveaux matériaux performants dans le domaine de la conduction protonique et ionique
The conductivity performance of a new series of chemically stable proton conducting Metal Organic Frameworks (MOFs) as well as a superionic molecular crystal was explored. The contribution of this PhD was to (i) select a variety of architectures and functionalities of robust MOFs/superionic molecular solids and (ii) characterize and rationalize their conducting performance over various temperature/humidity conditions. We designed two series of MOFs to achieve promising proton-conducting performance, using distinct approaches to modulate the concentration of Brønsted acidic sites and charge carriers and further boost the conductivity properties. First, a multicomponent ligand replacement strategy was successfully employed to elaborate a series of multivariate sulfonic-based solids MIP-207-(SO3H-IPA)x-(BTC)1–x which combine structural integrity with high proton conductivity values (e.g., σ = 2.6 × 10–2 S cm–1 at 363 K/95% Relative Humidity -RH-). Secondly, a proton conducting composite was prepared through the impregnation of an ionic liquid (1-Ethyl-3-methylimidazolium chloride, EMIMCl) in the mesoporous MIL-101(Cr)-SO3H. The resulting composite displaying high thermal and chemical stability, exhibits outstanding proton conductivity not only at the anhydrous state (σ473 K = 1.5 × 10-3 S cm-1) but also under humidity (σ(343 K/60%-80%RH) ≥ 0.10 S cm-1) conditions. Finally, the ionic conducting properties of another class of porous solids, considering a zirconium-formate molecular solid containing KCl ion pairs (ZF-3) were explored. ZF-3 switches from an insulator (σ = 5.1 x 10-10 S cm-1 at 363 K/0% RH) to a superionic conductor upon hydration (σ = 5.2 x 10-2 S cm-1 at 363 K/95 % RH), in relation with the boost of Cl- dynamics upon water adsorption. Noteworthy, quantum- and force-field based simulations were combined with the experimental approach to elucidate the microscopic mechanisms at the origin of the ionic conducting properties of the studied materials. This fundamental knowledge will serve to create novel robust superionic conductors with outstanding performances that will pave the way towards appealing societal applications for clean energy production

Metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) have become the focus of intense study over the past decade due to their potential for advancing a variety of applications including air purification, gas storage, adsorption separations, catalysis, gas sensing, drug delivery, and so on. These materials have some distinct advantages over traditional porous materials such as the well-defined structures, uniform pore sizes, chemically functionalized sorption sites, and potential for post-synthetic modification, etc. Thus, synthesis and adsorption studies of porous MOFs have increased substantially in recent years. Among various prospective applications, air purification is one of the most immediate concerns, which has urgent requirements to improve current nuclear, biological, and chemical (NBC) filters involving commercial and military purposes. Thus, the major goal of this funded project is to search, synthesize, and test these novel hybrid porous materials for adsorptive removal of toxic industrial chemicals (TICs) and chemical warfare agents (CWAs), and to install the benchmark for new-generation NBC filters. The objective of this study is three-fold: (i) Advance our understanding of coordination chemistry by synthesizing novel MOFs and characterizing these porous coordination polymers; (ii) Evaluate porous MOF materials for gas-adsorption applications including CO2 capture, CH4 storage, other light gas adsorption and separations, and examine the chemical and physical properties of these solid adsorbents including thermal stability and heat capacity of MOFs; (iii) Evaluate porous MOF materials for next-generation NBC filter media by adsorption breakthrough measurements of TICs on MOFs, and advance our understanding about structure-property relationships of these novel adsorbents.

The growing demand for clean water clashes with inadequate water availability. Human activities strongly affect the quality of water bodies, inducing their progressive chemical pollution. The sustainable management of water has become a crucial aspect to ensure both the quantity and the quality of water resources needed to support the demand. The limitations of conventional wastewater treatments in addressing the complete removal of contaminants from the effluents require the implementation of legislative measures to reduce the use of certain substances, together with a technological improvement of the treatment plants in order to protect the quality of water. The improvement of conventional treatments is achieved through the optimization of existing processes or their combination with new advanced treatment technologies. Recently, great efforts have been made towards the development of highly effective, robust and cost-effective composite materials to reduce the entering of aqueous contaminants in water bodies. The progress in nanotechnology offers promising solutions to address the water management challenges, thanks to the use of new advanced engineered nanomaterials in wastewater treatment. This thesis investigates the use of different techniques for the preparation of porous composite materials aimed at the removal of organic substances from water by means of adsorption processes or photocatalytic degradation. The micro- or nanosized active component is incorporated in a polymer-based matrix which ensures the formation of a solid composite that can be easily handled without requiring further expensive and time-consuming processes for its recovering from the treated water. The first proposed composite material is based on the valorization of agricultural waste for the preparation of a highly porous adsorbent through its combination with a biopolymer. Although their abundance and particular chemical composition make them promising low-cost adsorbents, the difficulties caused by their recovery after the water treatment may limit their manageability and applicability. The incorporation of an agro-waste powder in a solid porous system can overcome this limitation, without significantly compromising its adsorption capacity. Furthermore, using agro-waste as a low-cost active filler reduces the costs associated with water treatments and the volume of waste derived from food processing. The following porous composite materials include a photoactive nanomaterial inside the polymer-based matrix, for which the removal of organic compounds occurs by the heterogeneous photocatalytic process. This destructive process is indicated for the abatement of recalcitrant organic pollutants, since it may induce their complete mineralization. The incorporation of the active filler is investigated by using two different approaches, specifically an innovative in-situ fabrication procedure to form the nanomaterials directly inside the polymeric matrix, while for the second approach, the combination of the pre-synthetized nanomaterials to the polymer-based solution to obtain the porous composite. Different strategies to improve the photocatalytic performance of the porous composite materials are presented, studying the effect of the formation of heterostructures between the in-situ grown metal oxide and the noble metals on the photocatalytic degradation of organic contaminants. The proposed in-situ fabrication procedure ensures the formation of a metal oxide-based composite, characterized by a high surface area, flexibility and light weight for heterogeneous photocatalytic applications in water treatment, without the need of post-treatment steps for the removal of the photocatalysts from the treated water which may restrict their wide applicability as well as causing secondary pollution. The preliminary results of the incorporation of pre-formed metal oxide nanomaterials in a porous polymeric matrix are then presented, discussing possible future research.

In the last decades the development of new technologies is requiring new materials with enhanced emissive properties in the solid state to be applied in different fields spanning from OLED to biological applications. Research in this context is historically limited by the observation that luminogens possess better properties in dispersed system than in the condensed phase due to the well-known Aggregation Caused Quencing (ACQ) phenomenon. However, in 2001 Tang and co-workers reported some pioneering works on luminogens displaying opposite properties, being highly emissive in the condensed phase but not in diluted solution, a behaviour named Aggregation Induced Emission (AIE) [1]. Different mechanisms may explain the AIE phenomenon, the most frequent one being the inhibition of molecular motions (vibrations and rotations) which works as nonradiative deactivation channels for the molecule but are somehow locked in the aggregated state. In parallel, strong efforts have been devoted to the search of organic molecules with long-lived excited states that enable exciton migration over long distances for increased production of free charges. Usually, transitions from singlet (short-lived) to triplet (long-lived) states are facilitated by the presence of metals or specific organic moieties (i.e. aromatic aldehyde, heavy halogen atoms, heteroatoms with lone pairs). In addition, since triplet excitons generated in organic molecules are highly sensitive to oxygen and temperature, stringent conditions are required to observe long-lived phosphorescence from pure organic molecules. However, very recently, An et al. reported ultralong phosphorescent emission features in structures of planar organic molecules coupled in H-aggregates, which provide an effective means of stabilizing and protecting triplet excitons formed through intersystem crossing (ISC) [2]. The stabilized excited state, which functions as an energy trap at a lower energy level, may delocalize on several neighbouring molecules, offering suppressed radiative and nonradiative deactivation decay rates in favour of long-lived excited states and room temperature ultralong phosphorescence (RTUP). In this regard, during my research work, I have been involved in the synthesis and characterization of triimidazo[1,2-a:1',2'-c:1'',2''-e][1,3,5]triazine (TT or cyclic triimidazole) and of its derivatives. In fact, TT is an intriguing solid state luminogen characterized by AIE and RTUP properties. Diluted solutions of TT in DCM display weak emission (Ф = 2%) even under inert atmosphere, while crystalline powders (Ф = 30%) show an intense fluorescent emission at 425 nm and an ultralong emission at 520 nm with decay time close to 1 s. This behaviour, in agreement with works by An et al. [2] arises from the formation of H-aggregates in the crystal structure of the compound as revealed by XRD studies [3]. The main goal of my project has been the synthesis and characterization of organic and hybrid inorganicorganic 1. Luo, J.; Xie, Z.; Lam, J. W. Y.; Cheng, L.; Chen, H.; Qiu, C.; Kwok, H. S.; Zhan, X.; Liu, Y.; Zhu, D.; Tang, B. Z., Aggregation-induced emission of 1-methyl-1,2,3,4,5-pentaphenylsilole. Chemical Communications 2001, (18), 1740-1741. 2. An, Z.; Zheng, C.; Tao, Y.; Chen, R.; Shi, H.; Chen, T.; Wang, Z.; Li, H.; Deng, R.; Liu, X.; Huang, W., Stabilizing triplet excited states for ultralong organic phosphorescence. Nature Materials 2015, 14 (7), 685-690. 3. Lucenti, E.; Forni, A.; Botta, C.; Carlucci, L.; Giannini, C.; Marinotto, D.; Previtali, A.; Righetto, S.; Cariati, E., H-Aggregates Granting Crystallization-Induced Emissive Behavior and Ultralong Phosphorescence from a Pure Organic Molecule. The Journal of Physical Chemistry Letters 2017, 8 (8), 1894-1898.

Organic and hybrid organic-inorganic photovoltaic (PV) devices have the potential to provide low-cost, large scale renewable energy. Despite the tremendous progress that has been made in this field, device efficiencies remain low. This low efficiency can be partly attributed to the low open-circuit voltages (Voc) generated by organic and hybrid organic-inorganic PV devices. The Voc is critically determined by the energy-level alignment at the interface between the materials forming the device. In this thesis we use first-principles methods to explore the energy-level alignment at the interfaces between the conjugated polymer poly(3-hexylthiophene) (P3HT) and three electron acceptors, zinc oxide (ZnO), gallium arsenide (GaAs) and graphene. We find that Voc reported in the literature for ZnO/P3HT devices is significantly lower than the theoretical maximum and that the interfacial electrostatic dipole plays an important role in the physics underlying the charge transfer at the heterojunction. We note significant charge transfer from the polymer to the semiconductor at GaAs/P3HT interfaces, and use this result to help interpret experimental data. Our findings support the conclusion that charge transferred from P3HT to GaAs nanowires can passivate the surface defect states of the latter and, as a result, account for the observed decrease in photoluminescence lifetimes. Finally, we explore the energy-level alignment at the graphene/P3HT interface and find that Voc reported for experimental devices is in line with the theoretical maximum. The effect of functionalised graphene is also examined, leading to the suggestion that functionalisation might have important consequences for device optimisation.

[ES] En este trabajo de tesis doctoral, la investigación se ha centrado en el desarrollo de diferentes procesos catalíticos heterogéneos empleando materiales híbridos orgánico-inorgánicos porosos (MOFs y sílices funcionalizadas) y materiales orgánicos aromáti-cos (PAFs), que se han estudiado en diversas reacciones orgánicas. Tras la preparación de los MOFs en estudio, se han caracterizado sus propiedades estructurales y se han determinado sus centros activos en los clústeres metálicos (circonio, hafnio o cerio). La reactividad de estos MOFs y de los materiales híbridos sílice-aminas se ha estudia-do teniendo en cuenta sus centros catalíticos; estas reacciones se han optimizado lle-vando a cabo un estudio de los mecanismos de reacción. Finalmente, se han preparado sólidos homoquirales de tipo PAF que presentan el sistema binaftilo, cuya reactividad también ha sido probada. Más específicamente, en el capítulo 3 se ha estudiado la esterificación de amidas, que permite convertirlas en ésteres, grupos funcionales más versátiles. Esta transfor-mación se ha abordado desde la catálisis heterogénea via MOFs basados en circonio, hafnio y cerio de las series MOF-808, UiO-66 y MOF-801. El catalizador más eficien-te para la esterificación de amidas ha sido el MOF-808-Zr. Mediante análisis TGA y la adsorción de una molécula sonda básica (CO) estudiada utilizando espectroscopia FT-IR, se han determinado los centros ácidos de Lewis y Brönsted presentes en ellos. De los MOFs preparados en este trabajo, el MOF 808-Zr posee una menor conectividad de los clústeres metálicos y un mayor tamaño de poro mayor que el UiO-66 y el MOF-801; además, tiene el balance adecuado de centros ácidos y básicos de Brönsted y Lewis para activar los sustratos de la reacción. El alcance de la alcoholisis con n-butanol se ha extendido a un gran número de sustratos (amidas primarias, secundarias y terciarias; aromáticas y alifáticas). La reacción también se ha estudiado en condicio-nes no solvolíticas con alcoholes más complejos. El catalizador es estable durante la reacción y puede ser reutilizado fácilmente. El mecanismo de reacción en la esterifica-ción de benzamida con n butanol catalizada por MOF-808-Zr se ha investigado me-diante el análisis cinético empleando el modelo de LHHW y el estudio in situ de las interacciones moleculares por FT-IR. En el capítulo 4, se ha investigado la deuteración por intercambio isotópico deute-rio/hidrógeno catalizada por aminas soportadas en sílice comerciales empleando D2O como fuente de deuterio. Este procedimiento es aplicable a una gran gama de sustra-tos, como compuestos carbonílicos, sales de organofosfonio, nitrocompuestos e, inclu-so, hormonas esteroideas. La estabilidad del catalizador, SiO2-(CH2)3-NH2, se mantie-ne hasta en 10 usos de reacción sin pérdidas significativas de la actividad. Por último, en el capítulo 5, se afronta la síntesis y aplicación de PAFs homoquira-les donde se ha integrado el esqueleto del BINOL (1,1′-binaftil-2,2′-diol) y del BIN-BAM (1,1' binaftil-2,2'-disulfonimida) generando tres nuevos PAFs activos en catáli-sis asimétrica: PAF-3,3'-(S)-BINOL, PAF-6,6'-(R)-BINOL y PAF 3,3'-(S)-BINBAM. En concreto, el PAF-6,6'-(R)-BINOL ha demostrado su actividad catalítica en la reacción de alquilación de aldehídos aromáticos con dietil-zinc y el catalizador PAF-3,3'-(S)-BINBAM es activo en la reacción aldólica de Mukaiyama y la reducción del doble enlace de compuestos carbonílicos a,b-insaturados.
[CA] En aquesta tesi doctoral, la investigació s'ha centrat en el desenvolupament de dife-rents processos catalítics heterogenis emprant materials híbrids orgànic-inorgànics porosos (MOFs i sílices funcionalitzades) i materials orgànics aromàtics (PAFs), que s'han estudiat en diverses reaccions orgàniques. Després de la preparació dels MOFs en estudi, s'han caracteritzat les seues propietats estructurals i s'han determinat els seus centres actius en els clústers metàl·lics (zirconi, hafni o ceri). La reactivitat d'aquests MOFs i dels materials híbrids sílice-amines s'ha estudiat tenint en compte els seus cen-tres catalítics; aquestes reaccions s'han optimitzat duent a termini un estudi dels meca-nismes de reacció. Finalment, s'han preparat sòlids homoquirals de tipus PAF que presenten el sistema binaftilo, la reactivitat del qual també ha sigut provada. Més específicament, en el capítol 3 s'ha estudiat l'esterificació d' amides, que per-met convertir-les en èsters, grups funcionals més versàtils. Aquesta transformació s'ha abordat des de la catàlisi heterogènia via *MOFs basats en zirconi, hafni i ceri de les sèries MOF-808, UiO-66 i MOF-801. El catalitzador més eficient per a l'esterificació d'amides ha sigut el MOF-808-Zr. Mitjançant anàlisi TGA i l'adsorció d'una molècula sonda bàsica (CO) estudiada utilitzant espectroscopia FT-IR, s'han determinat els cen-tres àcids de Lewis i Brönsted presents en ells. Dels MOFs preparats en aquest treball, el MOF 808-Zr posseeix una menor connectivitat dels clústers metàl·lics i una major grandària de porus que el UiO-66 i el MOF-801; a més, té el balanç adequat de centres àcids i bàsics de Brönsted i Lewis per a activar els substrats de la reacció. L'abast de l'alcoholisi amb n-butanol s'ha estés a un gran nombre de substrats (amides primàries, secundàries i terciàries; aromàtiques i alifàtiques). La reacció també s'ha estudiat en condicions no solvolítiques amb alcohols més complexos. El catalitzador és estable durant la reacció i pot ser reutilitzat fàcilment. El mecanisme de reacció en l'esterifica-ció de benzamida amb n-butanol catalitzada per MOF-808-Zr s'ha investigat mitja-nçant l'anàlisi cinètica emprant el model de LHHW i l'estudi in situ de les interaccions moleculars per FT-IR. En el capítol 4, s'ha investigat la deuteració per intercanvi isotòpic deuteri/hidrògen catalitzada per amines suportades en sílices comercials emprant D2O com a font de deuteri. Aquest procediment és aplicable a una gran gamma de substrats, com a com-postos carbonílics, sals d'organofosfoni, nitrocompostos i, inclosa, hormones esteroi-dals. L'estabilitat del catalitzador, SiO2-(CH2)3-NH2, es manté fins a 10 usos de reac-ció sense pèrdues significatives de l'activitat. Finalment, en el capítol 5, s'afronta la síntesi i aplicació de PAFs homoquirals on s'ha integrat l'esquelet del BINOL (1,1′-binaftil-2,2′-diol) i del BINBAM (1,1'-binaftil-2,2'-disulfonimida) generant tres nous PAFs actius en catàlisi asimètrica: PAF-3,3'-(S)-BINOL, PAF-6,6'-(R)-BINOL i PAF 3,3'-(S)-BINBAM. En concret, el PAF-6,6'-(R)-BINOL ha demostrat la seua activitat catalítica en la reacció d'alquilació d'aldehids aromàtics amb dietil-zinc i el catalitzador PAF-3,3'-(S)-BINBAM és actiu en la reacció aldólica de Mukaiyama i la reducció del doble enllaç de compostos carbonílics a,b-insaturats.
[EN] In this Doctoral Thesis, the research has been focused on the development of different heterogeneous catalytic processes using hybrid porous organic-inorganic materials (MOFs and functionalized silicas) and organic aromatic materials (PAFs), which have been studied in various organic reactions. After the preparation of the MOFs under study, their structural properties have been characterised and their active centres in the metal clusters (zirconium, hafnium or cerium) have been determined. The reactivity of these MOFs and the hybrid silica-mine materials has been studied considering their catalytic centres; these reactions have been optimised by carrying out a study of the reaction mechanisms. Finally, homochiral PAF-type solids have been prepared with the binafil system, whose reactivity has also been tested. More specifically, the esterification of amides has been studied in Chapter 3. This reaction allows to convert the amides into esters, which are more versatile functional groups. This transformation has been approached from the heterogeneous catalysis via MOFs based on zirconium, hafnium and cerium of the MOF-808, UiO-66 and MOF-801 series. The most efficient catalyst for amide esterification has been MOF-808-Zr. Using TGA analysis and the adsorption of a basic probe molecule (CO) studied using FT-IR spectroscopy, the acid centres of Lewis and Brönsted present in them have been determined. Among the MOFs prepared in this work, MOF 808-Zr has a lower metal cluster connectivity and a larger pore size than UiO-66 and MOF-801; it also has the appropriate balance of acid and basic Brönsted and Lewis centres to activate the reaction substrates. The scope of n-butanol alcoholysis has been extended to a large number of substrates (primary, secondary and tertiary amides; aromatic and aliphatic). The reaction has also been studied in non-solvolitic conditions with more complex alco-hols. The catalyst is stable during the reaction and can be easily reused. The reaction mechanism in the esterification of benzamide with n-butanol catalysed by MOF-808-Zr has been investigated through kinetic analysis using the LHHW model and the in situ study of molecular interactions by FT-IR. In Chapter 4, the deuteration by isotopic deuterium/hydrogen exchange catalysed by commercial silica-supported amines using D2O as a source of deuterium has been investigated. This procedure is applicable to a wide range of substrates, such as carbonylic compounds, organophosphonium salts, nitro compounds and, even, steroid hormones. The stability of the catalyst, SiO2-(CH2)3-NH2, is maintained for up to 10 reaction uses without significant loss of activity. Finally, in Chapter 5, the synthesis and application of homochiral PAFs, in which the structure of BINOL (1,1′-binaftil-2,2′-diol) and BIN-BAM (1,1' binaftil-2,2'-disulfonimide) has been integrated, is discussed. Three new PAFs active in asymmetric catalysis has been generated: PAF-3,3'-(S)-BINOL, PAF-6,6'-(R)-BINOL and PAF 3,3'-(S)-BINBAM. In particular, PAF-6,6'-(R)-BINOL has demonstrated its catalytic activity in the alkylation reaction of aromatic aldehydes with diethyl zinc and the catalyst PAF-3,3'-(S)-BINBAM is active in the Mukaiyama aldolic reaction and the reduction of the double bond of carbonylic a,b-unsaturated compounds.
Villoria Del Álamo, B. (2021). Síntesis de catalizadores sólidos orgánicos e híbridos orgánicos-inorgánicos y su aplicación [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/163789
TESIS

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2002.
Includes bibliographical references (leaves 38-39).
With the development of porous materials for use as dielectrics in microelectronics processing, appropriate metrology tools are needed to monitor and characterize the pore size, distribution, and percent porosity in these films in an industrial setting. Techniques used to characterize and monitor porosity in thin films are oftentimes destructive, such as Transmission Electroil Microscopy and Scanning Electron Microscopy; indirect, such as optical ellipsometry and X-Ray Reflectivity; or pose problems for industrial use, involving radioactivity such as Positronium Annihilation Lifetime Spectroscopy and Small Angle Neutron Scattering. Atomic Force Microscopy is limited to surface analysis, and pores may be intersecting the surface at a variety of chords, not necessarily the diameter. Each of these techniques also has unique advantages, and a combination of these techniques can compensate for limitations such as inability to detect closed pores or constraints on pore size range of measurement. The following study is a round robin evaluation of these techniques using Developmental (Version 7) Porous SiLK(TM) from DOW Chemical (Midland, MI) manipulated to create pores of varying sizes. Optical tools and a possible in line X-Ray Reflectivity tool were found to be optimal for implementing porosity characterization in industry, since both techniques are commercially available, have proven high throughput, and can be clearly correlated to pore size and porosity in organic thin films.
by Yee Lam.
S.M.

Thesis (Ph. D.)--Dept. of Chemistry and School of Pharmacy. University of Missouri--Kansas City, 2005.
"A dissertation in chemistry and pharmaceutical sciences." Advisor: Zhonghua Peng. Typescript. Vita. Description based on contents viewed June 26, 2006; title from "catalog record" of the print edition. Includes bibliographical references (leaves 173-190). Online version of the print edition.

[EN] The present PhD thesis is centred in the design (using concepts of supramolecular chemistry), synthesis and characterization of different hybrid organic-inorganic materials for boron removal from aqueous media. The interaction between boron and organic groups, polyols, used in the development of these new adsorbents is also studied. In the first part of the thesis it is presented a brief review of supramolecular chemistry concepts, chemistry of boron and also the main methods for boron removal (first chapter) and, also, the objectives of this thesis (second chapter). The third chapter exposes the results obtained by using a ceramic foam as macroscopic support for active materials for boron removal. This support is previously "impregnated" with an inorganic silica mesoporous material (UVM-7) and, in a second step, it is functionalized with an organic group with high boron affinity (gluconamide). This organic group, which works as an adsorbent, remains anchored to a macroscopic support, which will facilitate the use of these materials in industrial applications. Once the material is synthetized their boron adsorption and elimination abailability in aqueous media is studied and its ulterior reutilization. The fourth chapter of the PhD thesis is focused on the preparation of low cost materials for boron adsorption from water. In first place, it is used, as inorganic scaffolding, UVM-7 material, a mesoporous silica phase with a bimodal pore system. This material has a high boron adsorption capacity after its functionalization with the polyalcohol (as it is shown in the previous chapter) nevertheless, the reagents used in the synthesis tetraethylorthosilicate, as silica source, and hexadecyltrimethylammonium bromide, as templating agent are so expensive that they induce a high cost of final materials. In this chapter is presented as an alternative another materials which are able to perform as inorganic scaffolds: UVM-11 (surfactant-free mesoporous material), two silica xerogels with pores within the mesoporous range and comercial high surface area silica fume were prepared. Once all the materials are synthetized they are functionalized with gluconamides which are the active compounds for boron adsorption. Finally, a comparative study of the boron adsorption capacities in water is carried out. Low cost materials present comparable boron removal to those of higher cost and comercially abailable materials. Finally, in the fith chapter of this PhD thesis, the adsorption mechanism of boron on the active materials (based on UVM-7 as inorganic support) is studied using solid Nuclear Magnetic Resonance measures of 11B and 13C and using techniques as Magic Angle Sppining, crossed polarization and heteronuclear polarization disacoplament. To do that, a hybrid material composed by UVM-7 matrix grafted with gluconamide is prepared and then the solid is put in contact with different boron quantities. Final solids are characterized through 13C and 11B NMR, showing the formation of boronesters between gluconamide diol groups and boron adsorbed. When low boron concentration is used, bisquelate complexes are formed (B:glucosa = 1:2), however with higher concentrations monoquelate complexes are formed (B:glucosa = 1:1). This work was carried out in collaboration with the research group of "sol-gel materials and NMR", appertaining to the center of "Chimie de la matière condensée de Paris" of the "Université Pierre et Marie Curie".
[ES] La presente tesis doctoral está dedicada al diseño (empleando conceptos de química supramolecular), síntesis y caracterización de diferentes materiales híbridos orgánico-inorgánicos para la eliminación de boro en medios acuosos. También se ha procedido a estudiar detalladamente la interacción del boro con las agrupaciones orgánicas, polialcoholes, empleadas en el desarrollo de estos nuevos adsorbentes. En la primera parte de la tesis de presenta una introducción en la que se revisa los conceptos de química supramolecular, química del boro y los principales métodos de eliminación de boro (primer capítulo) y, también, se exponen los objetivos de la tesis (segundo capítulo). Ya en el tercer capítulo se exponen los resultados obtenidos empleando una esponja cerámica como soporte macroscópico para los materiales activos frente a la eliminación de boro. Este soporte se "impregnan" previamente con un material inorgánico silíceo mesoporoso (UVM-7) y, en una fase posterior, se funcionaliza con un grupo orgánico con alta afinidad hacia el boro (gluconamida). El grupo orgánico que funcionará como adsorbente queda así anclado a un soporte de tamaño macroscópico que facilitará la aplicación de estos materiales a gran escala. Una vez preparado y caracterizado se estudió la capacidad del material para adsorber y eliminar boro de medios acuosos y su posterior reutilización. En el cuarto capítulo de la tesis doctoral se aborda la preparación de materiales adsorbentes de bajo coste económico para la eliminación de boro en medios acuosos. En primer lugar se emplea, como soporte inorgánico, UVM-7 una sílice mesoporosa con un sistema bimodal de poros. Este material tiene una capacidad de adsorción de boro muy elevada una vez funcionalizado con el correspondiente polialcohol (tal y como se expone en el capítulo anterior) sin embargo los reactivos para su síntesis tetraetilortosilicato como fuente de sílice y bromuro de cetiltrimetilamonio como agente director de estructura son muy caros con lo que el material final presenta un elevado coste. En este capítulo se presenta como alternativa otros materiales que puedan actuar como soportes inorgánicos: UVM-11, material mesoporoso que no requiere de agente director de estructura en su síntesis, dos xerogeles con poros en el rango meso y una sílice comercial nanoparticulada de elevada superficie específica. Una vez sintetizados y caracterizados los cinco soportes se funcionalizaron con gluconamidas, que son los componentes activos frente a la adsorción de boro. Finalmente, se realiza un estudio comparativo de la capacidad de eliminación de boro de los cinco materiales preparados. Los materiales de bajo coste estudiados presentan una capacidad de eliminación de boro comparable a los materiales de mayor coste y a los materiales comercialmente disponibles. Por último, en el capítulo cinco de esta tesis doctoral, se aborda el estudio del mecanismo de adsorción del boro en los materiales activos preparados (basados en UVM-7 como soporte inorgánico) mediante medidas de resonancia magnética nuclear de sólidos, tanto de 13C como de 11B empleando las técnicas de rotación en ángulo mágico, polarización cruzada, y el desacoplamiento dipolar heteronuclear. Para ello se prepara un material híbrido formado por una matriz de UVM-7 funcionalizada con gluconamidas y este sólido se pone en contacto con diferentes cantidades de boro. Los sólidos finales se caracterizan mediante RMN de 13C y de 11B, observándose la formación de boroesteres entre los grupos diol de las gluconamidas ancladas y el boro adsorbido. Cuando la concentración de boro empleada es baja se forman complejos bisquelados (B:glucosa = 1:2) mientras que a concentraciones altas empiezan a formarse complejos monoquelados (B:glucosa = 1:1). Este trabajo se llevó a cabo en colaboración con el grupo de investigación de "Materiales sol-gel y RMN", perteneciente al centro "Chimie de la matiè
[CAT] La present tesi doctoral està dedicada al disseny (empleant conceptes de química supramolecular), síntesi i caracterització de diferents materials híbrids orgànico-inorgànics per a la el¿liminació de bor en medi aquòs. També s'ha precedit a estudiar detalladament la interacció del bor amb les agrupacions orgàniques, polialcohols, empreats en el desenvolupament d'aquestos nous adsorbents. En la primera part de la tesi es presenta una introducció en la que es revisen els conceptes de química supramolecular, química del bor i els principals mètodes de el¿liminació de bor (primer capítol) i, també, s'exposen els objectius de la tesi (segon capítol). Ja en el tercer capítol s'exposen els resultats obtinguts empreant una esponja ceràmica com a suport macroscòpic per als materials actius front a l'el¿liminació del bor. Aquest suport s'impregna prèviament amb un material inorgànic de sílice mesoporós (UVM-7) i, en una següent fase, es funcionalitza amb un grup orgànic amb alta afinitat cap al bor (gluconamida). El grup orgànic que funcionarà com a adsorbent queda aixina anclat a un suport de tamany macroscòpic que facil¿litarà l'aplicació d'aquestos materials a gran escala. Una vegada preparat i caracteritzat s'estudia la capacitat del material per a adsorber i el¿liminar bor en medi aquós i la seua posterior reutilització. Al quart capítol de la tesi doctoral s'aborda la preparació de materials adsorbents de baix cost econòmic per a l'eliminació de bor en medi aquòs. En primer lloc, s'empra, com a suport inorgànic, UVM-7 una sílice mesoporosa amb un sistema bimodal de porus. Aquest material té una capacitat d'adsorció molt elevadadeprés de la seua funcionalització amb el corresponent polialcohol (tal i com s'exposa al capítol anterior), no obstant això els reactius que s'utilitzen per a la seua síntesi tetraetilortosilicat com a font de sílice i bromur de cetiltrimetilamoni com agent director d'estructura són molt cars, per tant el material final presenta un elevat cost. En aquest capítol es presenta com alternativa altres materials que puguen actuar com a suports inorgànics: UVM-11, material mesoporòs que no requereix d'agent director d'estructura durant la seua síntesi, dos xerogels en porus en el rang meso i una sílice comercial nanoparticulada amb elevada superficie específica. Una vegada sintetitzats i caracteritzats els cinc suports es funcionalitzen en gluconamides, que són els components actius front a la adsorció de bor. Finalment, es realitza un estudi comparatiu de la capacitat d'el¿liminació de bor dels cinc materials preparats. Els materials de baix cost estudiats presenten una capacitat de eliminació de bor semblant als materials de major cost i als materials comercialment disponibles. Per últim, al capítol cinc d'aquesta tesi doctoral, s'aborda l'estudi del mecanisme d'adsorció de bor als materials actius preparats (basats en UVM-7 com a suport inorgànic) mitjançant medides de resonància magnética nuclear de sólids, tant de 13C com de 11B emprant tècniques de rotació en àngul màgic, polarització creuada, i el desacoplament dipolar heteronuclear. Per a ell es prepara un material híbrid format per una matriu de UVM-7 funcionalitzada amb gluconamides i aquest sòlid es posa en contacte amb diferents quantitats de bor. Els sòlids finals es caracteritzen mitjançant RMN de 13C i de 11B observant-se la formació de borésters entre els grups diol de les gluconamides anclades i el bor adsorbit. Quan la concentració de bor emprada és baixa es formen complexos bisquelats (B:glucosa = 1:2) mentre que a concentracions més altes comencen a formar-se complexos monoquelats (B:glucosa = 1:1). Aquest treball és va realitzar ne col¿laboració amb el grup d'investigació de "Materials sol-gel i RMN", perteneixent al centre "Chimie de la matière condensée de Paris" de la "Université Pierre et Marie Curie".
Sanfeliu Cano, C. (2016). Organic-inorganic hybrid materials for boron removal from aqueous media [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/63277
TESIS

Doutoramento em Física
Luminescent solar concentrators are inexpensive devices that aim to increase the efficiency of photovoltaic cells and promote the urban integration of photovoltaic devices, with unprecedented possibilities of energy harvesting through the façade of buildings, urban furniture or wearable fabrics. Generally, they consist of a transparent matrix coated or doped with active optical centres that absorb the incident solar radiation, which is re-emitted at a specific wavelength and transferred by total internal reflection to the edges where the photovoltaic cells are located. The main objective of this work is the production of luminescent solar concentrators whose optically active layer is based on organic-inorganic hybrid materials doped with europium ions or organic dyes, in particular, Rhodamine 6G and Rhodamine 800. Rhodamine 800, as opposed to europium ions and Rhodamine 6G which emit in the visible range, emits in the near infrared (NIR) range, which is an advantage for crystalline Si-based photovoltaic cells, whose efficiency is greater in the NIR. In this work, although the luminescent solar concentrators with planar geometry are addressed, the main focus is the use cylindrical geometry. The use of this type of geometry allows the effect of concentration to be higher relative to the planar geometry, since the ratio between the exposed area and the area of the edges is increased. The cylindrical geometry is exploited by producing luminescent solar concentrators based on polymer optical fibre (plastic) where the optically active layer is on the outside (as a coating) or inside (as a filling in the hollow core) of the optical fibre. Furthermore, the possibility of increasing the exposed area was also dealt with the production of bundles of luminescent solar concentrators in which the plastic optical fibres are placed side by side and, also, by fabricating luminescent solar concentrators with length in the metre scale.
Os concentradores solares luminescentes são dispositivos de baixo custo que têm como objetivo aumentar a eficiência de células fotovoltaicas e promover a integração de dispositivos fotovoltaicos em elementos do dia-a-dia, tornando possível a captura de energia solar, através da fachada de edifícios, mobiliário urbano ou em têxteis. Geralmente, consistem numa matriz transparente coberta ou dopada com centros óticos ativos, capazes de absorver a radiação solar incidente e reemiti-la com um comprimento de onda específico que será transportada, através de reflexão interna total, para as extremidades da matriz onde se encontra(m) a(s) célula(s) fotovoltaica(s). O principal objetivo deste trabalho consiste na produção de concentradores solares luminescentes cuja camada ótica ativa é baseada em materiais híbridos orgânicos-inorgânicos dopados com iões lantanídeos (európio, Eu3+) ou corantes orgânicos, nomeadamente, Rodamina 6G e Rodamina 800. A Rodamina 800, ao contrário dos iões de európio e da Rodamina 6G que emitem na gama do visível, emite na região espetral do infravermelho próximo (NIR), que se revela uma vantagem quando a célula fotovoltaica em uso é composta de silício cristalino, cuja gama de maior eficiência é no NIR. Neste trabalho, apesar de serem abordados concentradores solares luminescentes com geometria planar, o principal foco é a utilização da geometria cilíndrica. Este tipo de geometria permite que o efeito de concentração seja superior, relativamente à geometria planar, uma vez que a razão entre a área exposta e a área das extremidades é aumentada. A geometria cilíndrica é explorada, através da produção de concentradores solares luminescentes com base em fibra ótica polimérica (plástica) em que a camada ótica ativa se encontra no exterior (como um revestimento) ou no interior (como um preenchimento do núcleo oco). Além disso, a possibilidade de aumentar a área exposta foi, também, abordada com o fabrico de uma matriz de concentradores solares luminescentes colocados lado a lado e, também, com o fabrico de concentradores solares luminescentes na escala do metro.

The acid and base catalyzed simultaneous twin polymerization (STP) of various 2,2′-disubstituted 4H-1,3,2-benzodioxasiline derivatives 2a–d with 2,2′-spirobi[4H-1,3,2-benzodioxasiline] (1) are presented in this paper. The products are nanostructured ternary organic–inorganic hybrid materials consisting of a cross-linked organic polymer, silica and a disubstituted polysiloxane. It can be demonstrated whether and in which extent the copolymerization of the two inorganic fragments of 1 and 2 takes place among the STP and how the molar ratio of the two components determines the structure formation of the resulting hybrid material. Steric and electronic effects of the substituents at the silicon center of 2 on the molecular structure formation and the morphology of the resulting hybrid material were investigated by means of solid state CP MAS 29Si and 13C NMR spectroscopy as well as high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The mechanical properties (hardness and Young's modulus) of the hybrid materials were analyzed by means of nanoindentation measurements
Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich

Ce mémoire rapporte la préparation et l'étude de matériaux hybrides organiques-inorganiques à base de titane où les deux réseaux sont liés par des liaisons titane-carbone stables. Différents précurseurs dans lesquels deux groupes cyclopentadienyltitane sont reliés par des espaceurs variés ont été préparés. Ces espaceurs comprennent des groupes aromatiques et hétéroaromatiques linéaires ainsi que des groupes aromatiques disubstitués par des chaînes alkyle. Ces complexes dimétalliques, où le titane est aussi lié à trois groupes labiles, ont été ensuite hydrolysés dans les conditions du procédé sol-gel pour conduire à des hybrides de classe II. Le réseau organique y est lié au réseau inorganique par des liaisons stables titane-carbone. Ces matériaux sont organisés et leur mode d'organisation dépend de la nature de l'espaceur reliant les groupes cyclopentadienyle. Les espaceurs linéaires conduisent à des matériaux à structure en escalier dans lesquels les ligands sont associés par des liaisons p. La longueur des espaceurs n'a pas d'effet sur cette organisation. Par contre, les matériaux à espaceurs substitués latéralement sont organisés par les chaînes alkyle. La calcination de ces matériaux hybrides sous oxygène conduit à la formation de dioxyde de titane nanoporeux sous forme d'anatase dont la cristallinité et la surface spécifique dépendent de la température de calcination. D'une façon similaire des films de dioxyde de titane de même type sont obtenus par la calcination de films minces d'hybrides préparés par spin-coating
This work aimed to the preparation of titanium-based organic-inorganic hybrid materials where both networks are linked through stable titanium-carbon bonds. The preparation of various di(cyclopentadienyltitanium) precursors in which various organic groups serve as a bridge between the two cyclopentadienyl groups while each titanium atom is equipped with three hydrolysable groups was first achieved. Then, these complexes were hydrolyzed in a sol-gel process that led to new self-assembled titanium-based class II hybrid materials in which the inorganic network is connected to the organic network through stable titanium-carbon bonds. The mode of organization of the nanostructures depends on the spacer bridging the cyclopentadienyl groups. Linear aromatic spacers led to materials having a stair-like structure in which the organic ligands are arranged via p-stacking. The length of the spacer has a little effect on the organization of the nanostructures. The structure of the materials obtained with spacers endowed with long lateral chains is governed by the side chains. The calcination of these materials under oxygen led to the formation of nanoporous anatase titanium dioxide the crystallinity and surface area of which depend on the calcination temperature. Similarly titanium dioxide thin films were prepared by the calcination of hybrid thin films prepared by spin coating

During this work, we have synthesised and completely characterised four new ligands, twenty two novel coordination complexes and thirteen new hybrid Metal- Organic Framework (supramolecular and coordination polymers) silver(I), Zinc(II) and copper(II)-containing with fascinating and intriguing structural architectures. To achieve these results under mild conditions, we have chosen three secondary building units or building blocks (SBU): cationic unit by the trinuclear copper [Cu3(μ3-OH)(μ- C3H3N2)3]2+, neutral complexes such as [M2(O2CC10H6CO2)].nH2O and [M3(C9H3O6)2]n.nH2O (where M = Cu(II), Zn(II), C9H3O6 3- = trianion of benzene tricarboxylic acid), O2CC10H6CO2 2- = dianionic naphthalene dicarboxylate) and finally the simple building unit, Zn(HCOO)2.2H2O. Their reactivity towards rigid or flexible "spacers" or "linker" such as 4,4 '-bipyridine (bpy), 1,2-bis(4-pyridyl)ethane has been investigated. After the literature overview, we have focussed our attention to the polyfunctional reactivity of the copper trinuclear triangular [Cu3(μ3-OH)(μ-C3H3N2)3]2+ cores. The reaction in methanol of copper trinuclear core [Cu3(C3H3N2)3(OH)(C3H4N2)2R2] ( with R = HCOO- or H3CCOO-) with 4,4'-bipyridine, trans-(1,2-bis(pyridin-4-yl))ethene and bis(pyridin-4-yl))ethane had generated five novel hybrid Metal-Organic Framework (MOFs) well characterised by single-crystal Xray diffraction, elemental analysis, InfraRed spectroscopy and Thermogravimetry Analysis (TGA). Using the 4,4'-bipyridine, the two iso-strutural MOFs 2-1 and 2-6 having intriguing structures, are isolated and crystallised in space group Ibam with a = 35.201(6) a'…, b = 13.843(2) a'…, c = 23.590(6) a'…, α = β= γ= 90°, Z = 4 for MOFs 2-1 and a = 36.098(3) a'…, b = 12.766(10) a'…, c = 24.031(2) a'…, α = β= γ= 90°, Z = 4 for MOF 2-6 . Their structure determination reveals that they have 3D supramolecular network based on the stacking of the interpenetrating 2D honeycomb layers also resulting from the self-assembly of the 22-membered macrocycles or monomeric copper hexanuclear cores. Replacing the 4,4'-bipyridine by the flexible and more longer connector trans-(1,2-bis(pyridin-4-yl))ethene in the slightly modify conditions had gave rise to the two supramolecular isomers MOF 2-2 and 2-3 which crystallise respectively in triclinic space group P1 and monoclinic space group P21/n with a = 14.3105(5) a'…, b = 15.3253(5) a'…, c = 16.4073(6) a'…, α = 99.7450(10)°, β = 108.313(2)°, γ = 98.198(2)°, Z = 1 (for MOF 2-2) and a = 24.9689(8) a'…, b = 17.2737(5) a'…, c = 29.6605(9) a'…, α = γ = 90°, β = 92.623(2)°, Z = 8 (for MOF 2-3). The rhombic grid 2D-MOF 2-2 was constructed with the self-organisation of the 26-membered macrocyles forming the monomeric unit through the strong intermolecular hydrogen bonds. This open network which exhibits various types of cavities is completely different to the polymeric 1D zigzag chain of the isomer MOF 2-3. When the 4,4'-bipyridine was replaced by the bis(pyridin-4-yl))ethane, flexible spacer with the same coordination sites , another 3D open framework, MOF 2-4 (triclinic space group P1, a = 12.5276(6) a'…, b = 13.6797(6) a'…, c = 15.5767(7) a'…, α= 92.059(2)°, β= 103.1640(10)°, γ = 92.201(2)°, Z = 2) was obtained. The polymeric crystal structure of this MOF or supramolecular coordination polymer was forming by the coordination of the branched bidimensional monomeric structure through one bis(pyridin-4-yl))ethane and the intermolecular hydrogen bonds. In these five MOF structures, there are Ï€-Ï€ interactions. These results indicate that the nature of the co-ligand or connector plays the critical role in the construction of these novel hybrid coordination polymers or Metal-Organic Frameworks. The second part of this report, described the synthesis of the new ligands and their reactivity towards metal ions of Group 11 and 12. In fact, these N-donors chelating and bridging ligands named (bis(indazol-1-yl)methane , Monoclinic with space group C2, a = 23.6048(7) a'…, b = 4.10040(10) a'…, c = 13.9516(4) a'…, α = 90°, β = 117.8300(10)° , γ = 90° , Z = 4; bis(indazol-2-yl)methane, Monoclinic with space group P21, a = 4.5053(3) a'…, b = 11.5398(8) a'…, c = 11.9930(8) a'…, α = 90°, β= 99.550(2)°, γ = 90°, Z = 2; 1-((indazol-2-yl)methyl)-indazole, Monoclinic with space group P21/c , a = 10.0876(5) a'…, b = 8.1834(4) a'…, c = 14.7602(7) a'…, α = 90°, β = 98.168(2)°, γ = 90°, Z = 4), and bis(4,5,6,7-tetrahydroindazol-1-yl)methane, orthorhombic with a space group Pccn, a = 19.1237(15) a'…, b = 8.4206(7) a'…, c = 8.4529(7) a'…, α = 90°, β = 90°, γ = 90°, Z = 4) have been synthesised using two methods: the reported well-known ''Phase Transfer Catalyst (PTC)'' and a new one here reported. The complementary confirmation of their structural characterisation was obtained from DFT calculations. By using these ligands, we have prepared and structurally characterised nine derivatives from their reaction with simple salts of d10 metals (silver(I), zinc(II), mercury(II) and Cadmium(II)). With the silver(I) salt, complex salts exhibiting the common tetracoordination on Ag(I), (3-10) [Ag(Bindm)2](NO3): monoclinic, space group P21/c, a = 11.3092(6) a'…, b = 12.2646(6) a'…, c = 20.1430(10) a'…, α= 90°, β= 98.080(2)°, γ = 90°, Z = 4 and (3-20) [Ag(Bitim)2](NO3): triclinic, space group P1, a = 9.1219(9) a'…, b = 14.2797(13) a'…, c = 24.510(3) a'…, α = 79.043(4)°, β= 79.298(3)°, γ = 77.068(3)°, Z = 4 containing two moieties Bindm or Bitim are reported. Also reported is a neutral derivative containing two ligands Bindm, showing the interesting six-coordination on Cd(II) (3-17) [CdCl2(Bindm)2]: triclinic, space group P1, a = 7.9331(12) a'…, b= 7.9480(12) a'…, c = 12.5068(18) a'…, α = 83.519(7)°, β = 72.527(7)°, γ = 67.587(6)° and Z= 1. With the mercury and zinc salts, it was observed that only one ligand molecule is chelating the metal centre which is then occupies the center of distorted tetrahedral. It is the case of the following five reported derivatives (3-21) [ZnCl2(Bitim)] (triclinic space group P1, a = 7.3686(18) a'…, b = 9.388(2) a'…, c = 12.975(3) a'…, α = 80.438(6)°, β= 74.252(6)°, γ = 86.260(7)°, Z = 2); (3-6) [ZnBr2(Bindm)] (Orthorhombic, space group Pnma, a = 13.2080(11) a'…, b = 14.2483(12) a'…, c = 8.5448(7) a'…, α= 90°, β= 90°, γ = 90°, Z = 4); (3-5) [ZnCl2(Bindm)](monoclinic, space group P21/m, a = 7.2900(11) a'…, b = 14.101(2) a'…, c = 8.2929(13) a'…, α= 90°, β= 112.802(4)°, γ = 90°, Z = 2); (3-11) [Hg(SCN)2(Bindm)](monoclinic, space group P21/n, a = 12.3387(5) a'…, b = 8.1098(3) a'…, c = 18.1621(7) a'…, α = 90°, β = 96.9590(10)°, γ = 90°, Z = 4) and (3-13) [HgCl2(Bindm)](triclinic, space group P1, a = 11.7136(5) a'…, b = 12.5791(5) a'…, c = 14.1761(6) a'…, α = 72.102(2)°, β= 71.534(2)°, γ = 79.366(2)°, Z = 2). Analogously to the work carried out in chapter 2, variety of diamine linkers (en, tn, pn, bipy, bipyetha, bipyethe) and/or monodentate N-donor ligand (pyrazole, imidazole and some of their derivatives) have been reacted at room temperature with a series of metal acceptors Zn(OOCH)2.2H2O, Zn(O2C-naph-CO2)2.3H2O or Zn(NDC)2.3H2O, Zn3(1,3,5-BTC)2.8H2O, CuNDC. 3H2O and Cu3(1,2,3-BTC)2.3H2O (where 1,3,5-BTC3- = 1,3,5-benzenetricarboxylate trianion, 1,2,3-BTC3- = 1,2,3-benzenetricarboxylate trianion and NDC2- = naphthalene dicarboxylate dianion) to obtain twenty nine new derivatives characterised by the elemental analysis, spectroscopic and X-ray diffraction techniques for someone. The reaction with zinc carboxylates have yielded the isolation of seventeen derivates among which five are completely structurally characterised: the complex derivative [Zn(imH)6](OOCH)2 (4-1), the coordination polymers 1D-MOFs (4-4){[Zn2(µ-OOCH)(OOCH)3(bipy)2(H2O)2].H2O}. and (4-7){[Zn2(OOCH)4(µ-bipyetha)].4H2O}. with a zig-zag array crystal structure; and finally, two inorganic supramolecular isomers, 1D-MOF [Zn2(OOCH)4(µ-bipyethe)]. (4-5)and 3D-MOF [Zn2(µ-OOCH)4(µ-bipyethe)(OH2)2]. (4-6). Their crystallographic parameters are the following: (4-1): Space group P21/a, a: 8.355 a'…, b: 16.9590a'… , c: 8.9400 a'…, α: 90°, β: 91.68°, γ : 90 ° ; (4-4): Orthorhombic with space group Pbca, a = 6.7651(8) a'…, b = 17.4876(19) a'…, c = 23.180(3) a'…, α = β = γ = 90°, Z = 8; (4-5): Monoclinic, P2/n, a = 8.8105(3) a'…, b = 4.8235(2) a'…, c = 16.4502(7) a'… , α= 90°, β= 102.9150(10)°, γ = 90° Z= 2; (4-6): Monoclinic, C2/c, a = 37.8876(14) a'…, b = 7.6025(3) a'…, c = 25.4422(9) a'…, α= 90°, β= 90.489(2)°, γ = 90° , Z = 8 and (4-7): Monoclinic, C2/c , a = 18.0718(9) a'…, b = 4.6178(3) a'…, c = 17.3126(9) a'…, α= 90°, β= 96.329(2)°, γ = 90°, Z = 4. We have equally isolated variety of copper(II) derivatives from which three were structurally characterised: the complex salt derivative [Cu(tn)2(H2O)2](NDC).3H2O (4- 26) which crystallises in system triclinic and Space group P1, a = 7.3274(2) a'…, b = 9.9798(3) a'…, c = 11.5687(3) a'…, α= 100.6210(10)°, β = 95.1010(10)°, γ= 97.6160(10)°, Z = 1; and two Metal-Organic Frameworks 1D {[Cu(NDC)(tn)(H2O)(µ-H2O)].1/2H2O}8 (4-25) crystallising in Monoclinic system and space group P21/c, a = 11.4293(4) a'…, b = 10.4074(4) a'…, c = 12.4403(5) a'…, α= 90°, β= 117.2450(10)°, γ = 90°, Z = 2 and 2D {[Cu3(1,2,3-BTC)2(en)3(µ-H2O)(H2O)3].3H2O}.(4-29) with a space group P-1, a =12.157(2) a'…, b=12.874(3) a'…, c=14.054(3) a'…, α= 75.08(3)°, β= 74.45(3)°, γ = 68.03(3)°. Similarly to the previous derivatives reported in chapter 2, the connector trans-(1,2-bis(pyridin-4-yl))ethene (bipyethe) reacted with zinc formate (simple unit) concomitantly gave rise to two supramolecular isomers. The MOFs (base either on zinc carboxylate or copper carboxylate derivatives) exhibit in the overall crystal structures various types of open cavities or channels with someone occupy with solvent or water molecules. The thermal analysis show that these MOFs could be considered as perspective materials for gas storage until to 180°C. During the last part of this work, devoted to the synthesis of new coordination compounds based on phosphorous donor (mono- or di-) and N-donor ligands, we have reported the preparation of twenty one new compounds where eleven are structurally and completely characterised. In more details, seven silver adducts (either monomeric or polymeric species) were structurally characterised from the interaction of silver(I)diethyldithiocarbamate (Ag(dtc)) with phosphorous donor (mono- or di-) ligands: monomeric species (5-7)[Ag(dtc)(PMePh2)2] (monoclinic with P21/c, a =10.2830(8)a'… , b = 30.099(2)a'… , c = 10.8760(8)a'…, β =115.990(2)°, Z = 4), (5-13) [Ag(dtc)(dppet)] (monoclinic with P21/n, a = 9.9615(9)a'… , b =17.923(2)a'… , c =16.932(2)a'…, β = 95.235(2)°, Z = 4); dimeric species (5-1) [Ag(dtc)(PPh3)]2 ( triclinic, space group P1, a=10.410(1)a'…, b = 10.641(1)a'…, c = 10.867(1)a'…, α = 92.523(3)°, β = 93.573(3)°, γ = 109.409(3)°, Z = 1 dimer ), (5-3) [Ag(dtc)(P-m-tolyl3)] (triclinic with space group P1, a = 10.373(1) a'…, b = 11.441(1) a'…, c = 12.275(2) a'…, α = 71.407(2)° , β = 68.949(2)°, γ = 84.512(2)°, Z = 1 dimer ), (5-8) [Ag(dtc)(dppm)]2 (monoclinic with space group C21/c , a = 24.022(6)a'…, b = 10.234(2)a'… , c = 27.114(4)a'…, β = 118.37(2)°, Z = 4 dimers), and polymeric species or 1D polymer (5-6) [Ag(dtc)(PMePh2)]. (monoclinic with P21/n, a = 13.041(1)a'… , b = 7.4238(6)a'… , c = 19.892(2)a'…, β = 93.237(2)°, Z = 4), (5-10) [Ag(dtc)(dppp)]. (monoclinic with P21/c, a = 14.880(2)a'… , b = 12.035(2)a'… , c = 18.025(2)a'…, β = 101.09(1)°, Z = 4). Apart from derivative (5-1) where Silver (I) is pentacoordinated (P2AgS3), all the derivatives exhibit the tetracoordination (P2AgS2 or PAgS3) on silver centre. By reacting variety simple salts of Cu(I) with the 2,9-dimethyl-1,10- phenanthroline (dmp), eight new copper (I) derivatives have isolated among which, four were structurally characterized: (5-14) [Cu(dmp)(MeCN)]NO3 (monoclinic with P21/c, a = 10.8080(4)a'… , b = 19.5740(8)a'… , c = 7.8400(3)a'…, β = 111.206(1)°), (5-15) [Cu(dmp)2]NO3 (monoclinic with C2/c, a = 17.648(4)a'… , b =11.698(2)a'… , c = 12.466(3)a'…, β = 113.61(3)°), (5-16) [Cu(dmp)2]ClO4 ( ), (5-17) [Cu(dmp)2]Cl (triclinic with space group P1, a = 12.799(3)a'… , b = 13.598(3)a'… , c = 18.688(4)a'…, α = 70.011(3)° , β = 80.498(3)°, γ = 64.332(3)°).

During the PhD, most of the efforts have been spent to study and to optimize the performance of third generation solar cells, such as dye sensitized solar cells (DSSCs) and hybrid organic/inorganic Perovskite solar cells (PSCs). In particular, the attention has been focused on optimization of the fabrication process and on the implementation of carbon based materials to optimize different aspects of the cell. An original technique, the Vacuum-vapor assisted solution processing (V-VASP) was designed and developed to deposit glassy perovskite films without an inert atmosphere, therefore with lower fabrication costs with respect to other deposition techniques. Both small (0.1 cm2) devices and large area modules (8.8 cm2) were fabricated with V-VASP showing good stability in air and humidity conditions without encapsulation. Moreover, the aforementioned technique was used to embed the carbon nanostructures (CNSs) such as single-wall carbon nanotubes (SWCNTs) and graphene nanoplatelets (GNPs) as conductive nanofillers in the P3HT hole transporting layer with the purpose to extend the life time and the power conversion efficiency (PCE) of PSCs. The acquire knowledge on graphene was exploited in DSSC technology to develop large area (43.3cm2) module replacing the conventional expensive platinum, necessary to catalyse the redox reaction of liquid electrolyte mediator at the counter electrode (CE). A graphene-based ink, produced by liquid phase exfoliation of graphite, was sprayed onto a transparent conductive oxide substrate to realize a large area, semi-transparent and cheaper CE. As a follow up of this activity, a tandem configuration was designed for large area DSSC module proving a PCE improvement respect to the single structure as well. Beyond photovoltaic applications, perovskite materials have the required properties to become winning materials for many optoelectronic devices. In this work, as a side activity, the perovskite was also used to fabricate a solution process photodiode. The good values of responsivity, detectivity and bandwidth measured, demonstrated the excellent versatility of perovskites and will pave the way for future implementation in low cost and high performance optoelectronics applications.

>Magister Scientiae - MSc
Due to the rapid depletion of fossil fuel reserves and the production of environmentally harmful by-products such as carbon dioxide, there is an urgent need for alternate sustainable clean energy. One of the leading candidates in this endeavour is hydrogen, which can be used as an energy carrier since it has a high energy density, zero emissions and is produced from non-depletable resources such as water. The major challenge hindering a hydrogen economy is the lack of safe and effective storage technologies for mobile applications. A prospective solution to this problem lies in the use of porous powdered materials, which adsorb the hydrogen gas. However, the integration of these powdered materials into a storage tank system, results in the pipelines being contaminated during filling cycles. This necessitates the shaping of the porous powdered materials. Among the many shaping techniques available, the electrospinning technique has been proposed as a promising technology since it is a versatile process that is easily scaled-up making it attractive for the applications of the study. Furthermore, the electrospinning process enables the synthesis of nano-sized fibres with attractive hydrogen sorption characteristics. In this regard, the current study employs the electrospinning technique to synthesise electrospun composite fibres for mobile hydrogen storage applications. After electrospinning three polymers, polyacrylonitrile (PAN) was selected as the most suitable polymer because it yielded bead-free electrospun fibres. However, the diameter of the PAN fibres was large/thick which prompted further optimisation of the electrospinning parameters. The optimised electrospinning conditions that yield unbeaded fibres within the desired diameter range (of 300-500 nm) were a PAN concentration of 10 wt%, a flow rate of 0.4 mL/h, a distance of 10 cm between the needle tip and collector plate, and an applied voltage of 8 kV. The study then progressed to the synthesis and characterisation of the pristine porous powdered materials which adsorb hydrogen gas. The porous powdered materials investigated were commercial zeolite 13X, its synthesised templated carbon derivative (ZTC) and Zr (UiO-66) and Cr (MIL-101) based metal-organic frameworks (MOFs). ZTC was synthesised via liquid impregnation coupled with chemical vapour deposition (CVD), and the MOFs were synthesised by the modulated solvothermal method. Analysis of the ZTCs morphology and phase crystallinity show that the carbon templated process using zeolites was successful, however, ZTC was amorphous compared to crystalline zeolite template. The BET surface area was assessed with the aid of nitrogen sorption isotherms for both zeolite 13X and ZTC, and values of 730 and 2717 m²/g, respectively were obtained. The hydrogen adsorption capacity for zeolite 13X was 1.6 wt% and increased to 2.4 wt% in the ZTC material at 77 K and 1 bar. The successful synthesis of well defined, crystalline MOFs was evident from X-ray diffraction and morphological analysis. The BET surface area and hydrogen adsorption for Zr MOF were 1186 m²/g and 1.5 wt%, respectively at 77 K and 1 bar. Cr MOF had a BET surface area of 2618 m²/g and hydrogen adsorption capacity of 1.9 wt% at 77 K and 1 bar. The main focus of the study was to synthesise electrospun composite fibres that can adsorb hydrogen gas and thus provide significant insight in this field of research. As such it examined composite fibres that incorporates porous powdered materials such as zeolite 13X, ZTCs, UiO-66 (Zr) MOF and MIL-101 (Cr) MOF and investigated their ability to adsorb hydrogen gas, which have not been reported previously. The synthesis of composite fibres was achieved by incorporating the porous powdered materials into the PAN resulting in a polymeric blend that was then electrospun. Morphological analysis illustrated that the porous powdered materials were successfully supported by or incorporated within the PAN fibres, forming composite fibres. The BET surface area of the 40 wt% zeolite-PAN and 12.5 wt% ZTC-PAN composite fibres were 440 and 1787 m²/g respectively. Zr MOF and Cr MOF composite fibres had a BET surface area of 815 and 1134 m²/g, respectively. The BET surface area had reduced by 40, 34, 31 and 57% for zeolite 13X, ZTC, Zr MOF and Cr MOF, respectively after these porous powdered materials were incorporated into PAN. The hydrogen adoption capacity for 40 wt% zeolite-PAN, 12.5 wt% ZTC-PAN, 20 wt% Zr MOFPAN and 20 wt% Cr MOF-PAN composite fibres was 0.8, 1.8, 0.9 and 1.1 wt%, respectively. This decrease was attributed to the limited amount of porous powdered materials that could be incorporated into the fibres since only 40 wt% of zeolite 13X, 12.5 wt% of ZTC and 20 wt% of the MOFs were loaded into their respective composite fibres. This was due to the fact that incorporation of greater amounts of porous powdered materials resulted in a viscous polymeric blend that was unable to be electrospun. It is evident from the study that electrospinning is a versatile process that is able to produce composite fibres with promising properties that can potentially advance the research in this field thus providing a practical solution to the problem of integrating loose powdered materials into an on-board hydrogen storage system.
CSIR Young Researchers Establishment Fund (YREF)