Thèses sur le sujet « Catalytic and optical properties »
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 50 meilleures thèses pour votre recherche sur le sujet « Catalytic and optical properties ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les thèses sur diverses disciplines et organisez correctement votre bibliographie.
Tabor, Christopher Eugene. « Some optical and catalytic properties of metal nanoparticles ». Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31794.
Texte intégralCommittee Chair: El-Sayed, Mostafa; Committee Member: Perry, Joseph; Committee Member: Wang, Zhong; Committee Member: Whetten, Robert; Committee Member: Zhang, John. Part of the SMARTech Electronic Thesis and Dissertation Collection.
Fan, Yinan. « Rational synthesis of plasmonic/catalytic bimetallic nanocrystals for catalysis ». Thesis, Sorbonne université, 2022. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2022SORUS189.pdf.
Texte intégralAmong several nanocatalysts, those based on noble metal NPs deserve particular attention because of their electronic, chemical and even optical properties (in the case of plasmonic-enhanced transformations). Platinum or palladium are well known for their remarkable catalytic properties, but they are expensive and their resources are limited. In addition, single component nanocatalysts can only lead to a limited range of chemical reactions. Thus, our strategy was to develop bimetallic nanocatalysts composed of two metal elements that can exhibit synergistic effects between their physicochemical properties and enhanced catalytic activity. We have thus designed bimetallic nanocatalysts of the core-shell type composed of a silver core and a platinum shell. The interest is to combine the high and efficient catalytic activities of the platinum shell surface with the highly energetic silver core capable of enhancing the activities of the shell through its plasmonic properties. In addition, these bimetallic NPs often exhibit superior catalytic activity due to the modification of the Pt-Pt atomic bonding distance (i.e. the strain effect). In this thesis work, Ag@Pt NPs have been synthesized via a two-step process using chemically synthesized spherical Ag NPs as seeds on the one hand and platinum complexes with oleylamine on the other hand which are then reduced on the surface of the seeds at a controlled temperature. Different Ag seed sizes from 8 to 14 nm with a very low size distribution (<10%) have been obtained by adjusting the reaction time, temperature ramp, Ag precursor concentration and final temperature during the synthesis. The control of the shell thicknesses (from 1 to 6 atomic layers) has been possible by adjusting the ratio of platinum precursor to silver seed concentrations. The catalytic activity of the core-shell Ag@Pt NPs was tested by a model reaction of reduction of 4-nitrophenol to 4-aminophenol by NaBH4 in aqueous phase. We have observed that the thickness of the Pt shell and the size of the Ag core influence the catalytic properties and led increased catalytic activity compared to pure silver or platinum. This was attributed to synergistic effects. Furthermore, we have observed an enhancement of the catalytic activity of Ag and Ag@Pt NPs under light irradiation. This is correlated to the generation of hot electrons in the Ag core. Finally, in order to develop a supported nanocatalysis platform, 3D self-assemblies also called supercrystals composed of Ag@Pt nanoparticles have been spontaneously obtained after deposition on a solid substrate due to their narrow size distribution and homogeneous shape. The catalytic activity of these supercrystals for the hydrogen evolution reaction (HER) has been studied by following in situ by optical microscopy the production of H2 gas nanobubbles. Three distinct behaviors in photo-catalytic activity (activity, intermittent activity and non-activity) have been observed on the supercrystals in the same region of interest. In addition, 50% of the assemblies were determined to be active for HER which was shown to be accompanied by oxidative corrosion of silver
Schwenk, Nicola [Verfasser], Todd B. [Gutachter] Marder et Ulrich [Gutachter] Schatzschneider. « Seeing the Light : Synthesis of Luminescent Rhodacyclopentadienes and Investigations of their Optical Properties and Catalytic Activity / Nicola Schwenk ; Gutachter : Todd B. Marder, Ulrich Schatzschneider ». Würzburg : Universität Würzburg, 2018. http://d-nb.info/1160188025/34.
Texte intégralMildner, Stephanie [Verfasser], Christian [Akademischer Betreuer] Jooß, Michael [Akademischer Betreuer] Seibt et Peter [Akademischer Betreuer] Crozier. « Pr1-xCaxMnO3 for Catalytic Water Splitting - Optical Properties and In Situ ETEM Investigations / Stephanie Mildner. Gutachter : Christian Jooß ; Michael Seibt ; Peter Crozier. Betreuer : Christian Jooß ». Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2015. http://d-nb.info/1076673627/34.
Texte intégralLee, Suyeon. « Synthesis and properties of mono and bi- metallic nanoparticles of noble metals ; towards fabrication of novel functional nanoparticles assemblies ». Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS580.
Texte intégralNoble metal nanoparticles (NPs) have attracted a great interest last years in various domains due to their distinct physical and chemical properties such as optical, catalytic or magnetic properties. In this thesis, we investigated the various approaches to integrate two metals in the same system, such as bimetallic nanoparticles, or binary superlattices to obtain new properties. We have developed seed-mediated growth method to rationally synthesis core-shell NPs Au(or Ag)@M (M=Ag, Pd, Pt). The impact of synthesis parameters such as concentration of metallic precursors, nature of ligands or temperature on key NPs parameters (core size, shell thickness, dispersity) was studied. The optical, vibrational and catalytic properties of different bimetallic NPs were characterized according to their structure, chemical composition, number of shell atomic layer and core crystallinities. In addition, binary NP superlattices, which are co-assembled from of two different complementary components were also reported. Several assembly conditions (effective size ratio, concentration ratio, deposition temperature, deposition method) were explored. The physical mechanism responsible for the observed structural variation was thus identified. A variety of crystalline structures for the binary superlattices such as AlB2, NaZn13, NaCl were produced. Finally, the magnetic properties of Fe2O3/Au NP binary superlattices were studied. They are determined by the interparticle distance of Fe2O3 NPs modulated by the insertion of Au NPs
Gozin, Yael. « Catalytic antibody 1E9 : properties and selectivity / ». Zürich : ETH, 2006. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=16475.
Texte intégralHörnlund, Erik. « Catalytic Properties of Protective Metal-Oxides ». Doctoral thesis, KTH, Materials Science and Engineering, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3506.
Texte intégralDiddams, P. A. « Sheet silicates : structure and catalytic properties ». Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356665.
Texte intégralSesay, I. M. « Redox properties of some catalytic oxides ». Thesis, Queen's University Belfast, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379618.
Texte intégralDordick, Jonathan Seth. « Unusual catalytic properties of horseradish peroxidase ». Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/16488.
Texte intégralMICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE
Bibliography: leaves 217-231.
by Jonathan Seth Dordick.
Ph.D.
Lesik, S. M., et I. M. Ivanenko. « Nickel ferrites and its catalytic properties ». Thesis, Sumy State University, 2018. http://essuir.sumdu.edu.ua/handle/123456789/67686.
Texte intégralCymes, Brittany Allison. « Catalytic Properties of Novel Microporous Minerals ». Miami University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=miami1587730697926361.
Texte intégralZiegler, Christoph. « Syntheses and Assemblies of Noble Metal Nanostructures ». Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-101781.
Texte intégralSilva, Patrícia Rodrigues da. « Lanthanide-organic frameworks for optical and catalytic applications ». Doctoral thesis, Universidade de Aveiro, 2013. http://hdl.handle.net/10773/11659.
Texte intégralEste projecto de doutoramento tem como objetivo isolar e caracterizar sistematicamente novos polímeros de coordenação, no estado sólido. A presença de grupos rígidos possuindo, em particular, átomos de oxigénio e de azoto, deverá induzir interessantes propriedades fotoluminescentes (rendimentos quânticos e tempos de vida elevados, assim como vias de transferência de energia eficientes), que poderão permitir a utilização dos compostos poliméricos na produção de dispositivos funcionais. As diferentes abordagens sintéticas foram ajustadas para cada material e basearam-se, preferencialmente, nas sínteses hidrotérmicas e nas assistidas por radiação de microondas. A estrutura dos materiais foi elucidada a partir de métodos de difracção de raios X (de cristal único ou de pós) em conjunto com outras técnicas, tais como RMN de estado sólido, microscopia eletrónica, análises térmicas, espectroscopia vibracional e estudos de composição elementar. Os compostos microcristalinos foram sistematicamente estudados a fim de investigar outras propriedades além das de fotoluminescência. Alguns dos materiais revelaram multifuncionalidade apresentando simultaneamente tempos de vida na ordem dos milisegundos, elevados rendimentos quânticos e elevado desempenho como catalisadores heterogéneos. As propriedades magnéticas de um composto baseado em érbio foram igualmente estudadas, assim como as de adsorpção e permuta de solvente de uma estrutura porosa baseada em cério.
This PhD programme aims to systematically isolate and characterise, in the solid state, novel coordination polymers. The presence of rigid groups having, in particular, oxygen and nitrogen atoms, is expected to induce interesting photoluminescent properties (high quantum yields and lifetimes, e cient energy transference pathways) which may allow the use of the polymeric compounds in the production of functional devices. Synthetic approaches have been ne-tuned for each material and were preferably based on hydrothermal and microwave-assisted syntheses. The structure of the materials was elucidated from X-ray di raction methods (single-crystal or powder data) in tandem with other techniques such as solid-state NMR, electron microscopy, thermal analyses, vibrational spectroscopy and elemental composition studies. The microcrystalline compounds were systematically studied in order to investigate other properties besides the photoluminescence. Some of the materials revealed multifunctional behaviour since they presented simultaneously life times in the order of milliseconds, high quantum yields and high performance as heterogeneous catalysts. The magnetic properties of an erbium-based compound were also studied, as well as the adsorption and solvent exchange behavior of a porous structure based on cerium.
Bi, Melody. « Characterization and Catalytic Properties of Sulfated Zirconia ». TopSCHOLAR®, 1996. http://digitalcommons.wku.edu/theses/895.
Texte intégralSimmons, Donald Karl. « Acid catalytic properties of metallosilicate molecular sieves ». Thesis, Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/10151.
Texte intégralCarabineiro, Hugo. « Structure and catalytic properties of tungstated zirconia ». Paris 6, 2005. http://www.theses.fr/2005PA066122.
Texte intégralRaj, A. « Catalytic properties of some metallosilicate molecular sieves ». Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 1993. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/3065.
Texte intégralUrban, Joanna. « Optical and vibrational properties ». Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30092.
Texte intégralAtomically thin layered materials with low symmetry which leads to in-plane anisotropy of electronic and optical properties are particularly interesting from the point of view of applications. In this thesis, the optoelectronic properties of three layered materials within-plane anisotropy, black phosphorus, rhenium disulfide and franckeite are investigated using optical spectroscopy. Black phosphorus (BP), with a puckered orthorhombic structure, has significant in-plane anisotropy and a direct bandgap which varies strongly with the number of layers. A significant hindrance from the point of view of the realization of BP-based devices is its degradation in ambient conditions, which can be prevented by encapsulation, for example using hexagonal boron nitride (h-BN). We have investigated the vibrational properties of h-BN encapsulated black phosphorus using Raman spectroscopy and report the first experimental observation of a theoretically predicted new peak slightly above the A1g mode. We explain its appearance by a difference of the mode frequencies in the inner and surface layers and discuss this effect in the context of the strong interlayer coupling in BP and the influence of the encapsulation on the lattice properties. The second part of this thesis presents the results of photoluminescence studies of few-layer rhenium disulfide. The optical response of ReS2is dominated by two energetically nondegenerate anisotropic excitons X1around 1.55 eV and X2 around 1.57 eV which can be observed in polarized absorption and emission. A controversy exists regarding the nature of the fundamental bandgap of ReS2, in particular the presence of a crossover from indirect to direct bandgap with changing thickness. We have studied the polarized emission related to the excitonic states at low temperature as a function of the number of layers and compared the experimental results with the predictions of a kinetic model describing the radiative recombination and scattering between excitonic states. We conclude that the features observed in photoluminescence arise due to hot emission from direct excitonic states and that a smaller, indirect bandgap and a related excitonic state are responsible for the depopulation of the direct states, the relatively weak emission intensity and the observed X1and X2 emission ratio. Franckeite, a complex sulfide mineral, has attracted attention as a natural type-II heterostructure composed of alternating pseudo-hexagonal and pseudo-tetragonal layers. The incommensurate character of the two lattices leads to one-dimensional rippling. The last part of this thesis describes our observation of anomalous polarization dependence of the Raman modes in exfoliated franckeite flakes, which suggested the presence of optical anisotropy and could be used as a rapid and non-invasive method to identify the rippling direction
Gleeson, H. F. « Optical and electro-optical properties of chiral mesophases ». Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383374.
Texte intégralAlshammary, Marzook. « Optical and magneto-optical properties of doped oxides ». Thesis, University of Sheffield, 2011. http://etheses.whiterose.ac.uk/2066/.
Texte intégralHathcock, David Jackson. « Dynamic and Catalytic Properties of Some Metallic Nanoparticles ». Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5134.
Texte intégralStanbridge, Nicholas Henry John. « Physical and catalytic properties of high silica faujasites ». Thesis, University of Nottingham, 1995. http://eprints.nottingham.ac.uk/13649/.
Texte intégralGleeson, David. « Preparation, characterisation, catalytic properties of novel mesoporous materials ». Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265634.
Texte intégralLinaza, Sabin. « Catalytic properties of antibodies in [4+2] cycloaddition ». Thesis, University of Strathclyde, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248702.
Texte intégralJacobsen, S. M. « Chemical, catalytic and spectroscopic properties of titanium (II) ». Thesis, University of Strathclyde, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381356.
Texte intégralXu, Jiahui. « Catalytic properties of nano ceria in heterogeneous catalysis ». Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:02e68ff9-ce28-475a-bd08-6b60bcda64e7.
Texte intégralLee, Adam Fraser. « Structural and catalytic properties of bimetallic Pd systems ». Thesis, University of Cambridge, 1995. https://www.repository.cam.ac.uk/handle/1810/273061.
Texte intégralMăicăneanu, A. « Atomistic simulation of oxide materials with catalytic properties ». Thesis, Department of Environmental and Ordnance Systems, 2009. http://hdl.handle.net/1826/3249.
Texte intégralDylla, Anthony Greg. « Synthesis, characterization and catalytic properties of bimetallic nanoparticles ». College Park, Md. : University of Maryland, 2009. http://hdl.handle.net/1903/9609.
Texte intégralThesis research directed by: Dept. of Chemistry and Biochemistry. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Cui, Jianyi. « Catalytic properties, densification and mechanical properties of nanocrystalline yttria-zirconia-based materials ». Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/41679.
Texte intégralIncludes bibliographical references.
Alumina, titania, ceria and manganese oxide were either coated onto or doped in cubic 7 mol% Y203-ZrO2 (7YZ) nanocrystals to form nanocomposites for methane combustion. These novel catalysts were very active and thermally stable. In particular, 25 wt% Mn203-coated 7YZ and 25 wt% Mn203-doped 7YZ showed remarkably low light-off temperatures of 3750C and 3580C, respectively. These catalysts were highly attractive as they were competitive with the much more expensive supported noble metal catalysts. Their catalytic activity could be attributed to the availability of active surface oxygen species, which facilitated the methane activation at low temperatures. Nanocrystalline 3 mol% and 8 mol% Y203-ZrO2 (3YZ and 8YZ) were successfully densified with an ultrafine grain size of < 90 nm by pressureless sintering at 11000C and 11500C, respectively. The low-temperature sinterability could be attributed to the well-defined nanocrystalline particles obtained via hydrothermal synthesis, and the effective elimination of secondary porosity through the dry compact processing. Submicron-sized 3 mol% Y203-ZrO2 ceramics with a grain size of - 150 nm was also obtained with commercial TOSOHC powders. Grain growth during densification of TOSOH© powders was successfully suppressed by presintering to 93% density under an argon atmosphere, followed by hot isostatic pressing at a temperature lower than the presintering temperature. The grain sizes of dense 3YZ and 8YZ ceramics were controlled between 100 nm and 5 glm. This allowed for the systematic study of 3YZ and 8YZ in indentation hardness, Young's modulus and fracture toughness as a function of grain size through micro-indentation and instrumented nano-indentation.
(cont.) The Hall-Petch effect was found to be extended to the nanocrystalline regime for 3YZ. 8YZ showed the Hall-Petch effect only in the micrometer and submicrometer regime. Maximum Hv values of 19 and 20 GPa were achieved for 3YZ and 8YZ, respectively. A continuous decrease in Young's modulus with decreasing grain size was observed in both 3YZ and 8YZ. This could be partially explained by the percolation theory. Transgranular fracture was observed in 3YZ as the grain size approached - 100 nm. This was in contrast with the dominant intergranular fracture mode observed in ceramics with fine grain sizes. Transgranular fracture was found in 8YZ over an even broader range of grain sizes (150 nm to 5.0 glm). A significant reduction in fracture toughness from 7.9 MPam-1/2 to 3.1 MPa-m1/2 was observed as the grain size was reduced from 1.1 im to 100 nm in 3YZ. Fracture toughness was much lower for 8YZ than for 3YZ, and showed little dependence on grain size. The stability of tetragonal phase at small grain sizes could account for the considerable reduction in the fracture toughness in 3YZ, and the transgranular fracture mode as grain size approached 100 nm.
by Jianyi Cui.
Ph.D.
Millesi, Salvatrice. « Assembly of Functional Nanostructures for Optical, Electrical or Catalytic Systems ». Doctoral thesis, Università di Catania, 2016. http://hdl.handle.net/10761/3962.
Texte intégralPapapanayotou, I. « Chemical properties and optical properties of carbonaceous particles ». Thesis, University of Leeds, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383288.
Texte intégralAuguié, Baptiste. « Optical properties of gold nanostructures ». Thesis, University of Exeter, 2009. http://hdl.handle.net/10036/73955.
Texte intégralCrook, Robert J. « Optical properties of organic waveguides ». Thesis, University of Exeter, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359604.
Texte intégralZhou, Yuming. « Optical properties of living organisms ». Thesis, Open University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301878.
Texte intégralWan, Wai Man Vivian. « Optical properties of conjugated polymers ». Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621328.
Texte intégralRosenow, Judith. « Optical Properties of Condensation Trails ». Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-205659.
Texte intégralLanglebige Kondensstreifen sind Eiswolken, welche durch Kondensation von Wasserdampf an Rußpartikeln in einer eisübersättigten Atmosphäre entstehen. Der Wasserdampf entstammt einerseits aus dem Triebwerkabgas und andererseits aus der Atmosphäre. Kondensstreifen können die Atmosphäre durch Rückstreuung solarer Strahlung kühlen und durch Rückstreuung und Absorption terrestrischer Strahlung erwärmen. Der Einfluss von Kondensstreifen auf den Wärmehaushalt der Atmosphäre und damit die Antwort auf die Frage nach dem dominierenden Effekt wurde bisher zumeist auf globaler Ebene ermittelt, wobei der Kondensstreifen als planparallele Schicht mit konstanten optischen Eigenschaften angenähert wurde. Individuelle Kondensstreifen und der Einfluss des Sonnenstandes wurden bisher nur mithilfe eines groben Rasters betrachtet und niemals unter Berücksichtigung der Flugleistung des Luftfahrzeuges, welches den Kondensstreifen generiert hat. Für eine Trajektorienoptimierung sind jedoch präzise Berechnungen des Strahlungseinflusses und eine gewissenhafte Berücksichtigung der Flugleistung notwendig. Nur so kann der zukünftige Luftverkehr die Haupteinflussfaktoren der Flugeigenschaften auf den Strahlungseinfluss der Kondensstreifen berücksichtigen. Aus diesem Grund wurde in dieser Arbeit ein Modell entwickelt, welches die Eigenschaften des Strahlungstransfers durch den Kondensstreifen kontinuierlich bestimmt und die aus der Flugleistung resultierenden Parameter berücksichtigt
Khan, Saima Ishfaque. « The optical properties of metamaterials ». Thesis, University of Glasgow, 2016. http://theses.gla.ac.uk/7781/.
Texte intégralGonzález, Ganzábal A. (Alejandro). « Optical properties of leaf replicas ». Master's thesis, University of Oulu, 2018. http://urn.fi/URN:NBN:fi:oulu-201808232657.
Texte intégralLee, Timothy. « Nonlinear properties of optical microfibres ». Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/355529/.
Texte intégralMolloy, Peter J. « Optical properties of concentrated dispersions ». Thesis, London Metropolitan University, 1986. http://repository.londonmet.ac.uk/2939/.
Texte intégralBlack, Serra Ashley Phillip. « New oxynitride materials with luminescent, magnetic and catalytic properties ». Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/405378.
Texte intégralIn recent years oxynitride materials have received increasing attention because of their emerging applications as photocatalysts, phosphors, pigments, dielectrics and magnetic materials. This thesis reports the synthesis and characterization of two new oxynitride phosphors with potential application in warm white light LED technologies. The new compounds LaSrSiO3N and LaBaSiO3N activated with Eu2+ are orange-red light-emitting luminescent materials under excitation in the UV-blue range. We also report that the solid solution Sr2-xLaxSiO4-xNx (0≤ x ≤1), can be obtained by concomitant substitution of Sr2+ by La3+ and O2- by N3- in Sr2SiO4. By controlling the composition the emission colours can be tuned from yellow (x = 0.2) to orange-red (x = 1) for Eu2+ phosphors and from blue-green (x = 0.2) to orange-yellow (x = 1) in Ce3+ doped samples. On the other hand, this thesis has been directed towards the synthesis and study of new oxynitride perovskites extending the range of this group of compounds to the transition metals Cr and Hf. LnCrO3-xNx perovskites with Ln = La, Pr and Nd and nitrogen contents up to x = 0.59 have been synthesised through ammonolysis of LnCrO4 precursors. Nitride substitution induces oxidation of Cr3+ to Cr4+ as the mechanism of charge compensation and the consequences of this on magnetic ordering transitions have been studied. Hole-doping through O2-/N3- anion substitution suppresses magnetic order but far less drastically than Ln3+/M2+ (M = Ca, Sr) cation substitutions. Finally, we show the synthesis, structure, electrical and photocatalytic properties of new hafnium oxynitride perovskites LnHfO2N where Ln= La, Pr, Nd and Sm, and the previously reported analogous compound LaZrO2N. They crystallize in the orthorhombic GdFeO3-type superstructure and show band gaps between 3.4 and 2.8 eV. The time course of O2 and H2 evolution under Xenon lamp 300 W irradiation showed that the hafnium perovskites have the adequate oxidation and reduction potential to conduct the overall water splitting reaction in presence of a sacrificial agent. Dielectric and resistivity measurements showed that both Hf and Zr perovskite oxynitrides are electric insulators with dielectric constants between 16 and 30 at room temperature.
Roychowdhury-Saha, Manami. « Ribonucleic acid architecture dictates its binding and catalytic properties ». [Bloomington, Ind.] : Indiana University, 2005. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3204290.
Texte intégralSource: Dissertation Abstracts International, Volume: 67-01, Section: B, page: 0253. Adviser: Donald H. Burke. "Title from dissertation home page (viewed Feb. 9, 2007)."
Duarte, M. A. « Structure and catalytic properties of platinum on vanadium oxides ». Thesis, Brunel University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375486.
Texte intégralHuang, Xing. « Structure and Catalytic Properties of Ultra-Small Ceria Nanoparticles ». UKnowledge, 2014. http://uknowledge.uky.edu/cme_etds/25.
Texte intégralOno, Luis. « IN-SITU GAS PHASE CATALYTIC PROPERTIES OF METAL NANOPARTICLES ». Doctoral diss., University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3277.
Texte intégralPh.D.
Department of Physics
Sciences
Physics PhD
Bartley, G. J. J. « Preparation and catalytic properties of zirconium pillared interlayer clays ». Thesis, University of Reading, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379305.
Texte intégralDavis, Jack B. A. « Elucidating the structures and catalytic properties of metallic nanoparticles ». Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/6297/.
Texte intégralIslam, Shams Tania Afroza. « The catalytic properties of Fe-S cluster containing enzymes ». Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:eba9a2de-52fb-4da8-88e2-1fb0c2f69998.
Texte intégral