Дисертації з теми "Nanocatalysi"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 дисертацій для дослідження на тему "Nanocatalysi".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
Vivien, Anthony. "Complexes de cobalt(I) : synthèse raisonnée de nanocristaux mono- ou bimétalliques et applications catalytiques." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS235.
Повний текст джерелаNanocatalysis universe is a field which is yet to be explored, especially because of the difficult access to simple and well-controlled nanoparticles and their uses in heterogeneous catalyzed reactions. In this work, we show that it is possible to obtain hcp cobalt nanoparticles starting from the easily accessible CoCl(PPh3)3 and by simply heating it in oleylamine. The mechanism of this reaction based on the disproportionation of the cobalt(I) was proved by experimental and theoretical studies. We also demonstrate that it is possible to control the size and the shape of those nanoparticles by changing some parameters like the reaction time or the nature of the organometallic precursor. Moreover, by using the same protocol with other metals (especially nickel) we were able to obtain nanoparticles and then to form CoxNi1-x bimetallic alloys. Our nanoparticles were used for hydrogenation and hydrogen transfer reactions in presence of NH3BH3 (mainly on alkynes) giving good conversions and selectivities. We then compare those results with homogeneous catalysis, using different cobalt complexes. We made an in-depth study of this homogeneous catalysis which shows once again the efficiency of cobalt (as nanoparticles or organometallic complexes) on hydrogenations and hydrogen transfers. Those results offer new opportunities concerning the use of non-noble metals for the storage and the use of dihydrogen, allowing easier access towards energy applications
Giorgi, Pascal. "Nouvelles réactions à économie d'atomes et d'étapes basées sur la catalyse par des nanoparticules d'or et la multicatalyse. Applications dans la synthèse de chimie fine et des odorants." Thesis, Université Côte d'Azur (ComUE), 2017. http://www.theses.fr/2017AZUR4127.
Повний текст джерелаElaboration of synthetic methods based on metal-catalyzed reactions has been a hot topic in organic chemistry. Despite good efficiency, catalysis proceeding homogeneously, are limited in the operation of recovering/recycling of the catalysts. An important stress was placed to design catalysis, offering both the efficiency of homogeneous catalysts and the recyclability of heterogeneous catalysts. In this context, metal nanoparticles merged as a key tool, due to their unique physical and chemical properties. Notably, Au NPs have shown remarkable catalytic activity in the oxidation of activated alcohols under O2 atmosphere. Since now, the access to more complex molecules is the next step forward for this field, we envisioned multicatalytic roads, based on the oxidation of activated alcohols via supported Au NPs. Our choice of using solid catalysts was relevant, since nanostructured catalysts for which the fraction of active sites are located on the surface, limit the risk of cross-quenching. The latter carbonyl formed, could be further converted in situ, via tandem protocol. Herein, we developed novel, atom- and step-economical bicatalytic one-pot processes, to access substituted chromenes/quinolines (53-93%) by tandem oxidation/hetero-Michael addition/aldolisation combining nanocatalysis and base catalysis, ortho-THCs (50-81%) via tandem oxidation/arylation/cyclisation combining nanocatalysis and supported catalysts and a tandem cascade oxidation/hydrolysis to access HMLA (86%, sel 93%). A large panel of products of biological activity relevance, pertaining to the fragrance chemistry or aiming in some cases, pre-industrial scalability via continuous flow applications
Garlyyev, Batyr. "Synthesis and catalytic study of shell-shell, core-shell hollow gold nanocatalysts." Diss., Georgia Institute of Technology, 2016. http://hdl.handle.net/1853/54996.
Повний текст джерелаGaikwad, A. V. "Nanocatalysts properties and applications /." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2009. http://dare.uva.nl/document/125006.
Повний текст джерелаLiu, Qiaoran. "Photocatalytic performance of nanocatalysts." Thesis, Curtin University, 2021. http://hdl.handle.net/20.500.11937/88099.
Повний текст джерелаLing, Huajuan. "Development of Novel Nanocatalysts for Green Chemical Processes." Thesis, The University of Sydney, 2017. http://hdl.handle.net/2123/17708.
Повний текст джерелаBroderick, Meghann. "Characterization of Stabilized Palladium Nanocatalysts." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2201.
Повний текст джерелаBenkirane, Olivia. "New perspectives in nanocatalysis using design of experiments." Doctoral thesis, Universitat Rovira i Virgili, 2018. http://hdl.handle.net/10803/665618.
Повний текст джерелаEl uso de catalizadores activos y selectivos en procesos industriales puede minimizar la formación de residuos no reciclables. Entre los procesos catalíticos más comunes, la semi-hidrogenación de alquinos en alquenos ha sido objeto de especial atención por su relevancia en las industrias petroquímica, de polímeros y de química fina. La selección de catalizadores heterogéneos apropiados puede mejorar la productividad y evitar problemas de sobre hidrogenación y/o oligomerización. Esta tesis trata de la síntesis y caracterización de nuevos catalizadores coloidales para su aplicación en reacciones de hidrogenación selectiva utilizando diseño de experimentos (DOE). Se proponen nuevas síntesis de nanopartículas de Pd, así como metodologías eficientes para la planificación de experimentos, demostración de reproducibilidad y tratamiento analítico de datos de TEM. Se estudió la relación estructura-síntesis de nanopartículas utilizando DOE y se evaluó el efecto de varios parámetros sobre el tamaño, distribución y forma de las nanopartículas así como sobre la eficacia de la síntesis. Los parámetros e interacciones clave se resaltaron obteniendo una receta de nanopartículas coloidales bien definidas. La impregnación de estas nanopartículas en diferentes soportes catalíticos se realizó utilizando síntesis de una y dos etapas y se estudió el efecto de la inmovilización, los parámetros de síntesis, el soporte catalítico, el contenido de Pd y la relación de síntesis sobre el tamaño y dispersión de las NPs. Finalmente, se realizó un estudio cinético de la hidrogenación con 1-octino sobre cuatro catalizadores soportados usando DOE. La concentración de 1-octino, la presión de hidrógeno y la temperatura se modificaron según los experimentos diseñados, y solo fueron necesarias 24 pruebas catalíticas para obtener expresiones cinéticas robustas que permitieron comparar el rendimiento de los catalizadores. Esta tesis ofrece un análisis profundo del diseño de nuevos nanocatalizadores basados en Pd para su aplicación en reacciones de semi-hidrogenación de alquinos utilizando metodologías prácticas y efectivas.
Heterogeneous catalysts offer an essential tool to achieve a suitable use of energy and chemicals. Indeed, the use of active and selective catalysts in industrial processes can minimize the formation of non-recyclable waste. Among the most commonly applied catalytic processes, the semi-hydrogenation of alkynes into alkenes has been the object of particular attention for its relevance in the petrochemicals, polymer and fine chemical industries. Indeed the selection of proper heterogeneous catalysts derives in productivity improvements preventing over-hydrogenation and/or oligomerization issues. The thesis dealt with the synthesis and characterization of novel catalysts prepared by colloidal approach for application in selective hydrogenation reactions using design of experiments methodology (DOE). Novel synthesis of colloidal Pd NPs was proposed as well as efficient methodologies for the experiment planning, reproducibility demonstration and analytical treatment of TEM data. Two NPs structure-synthesis relationship studies were performed using DOE. The effect of several parameters on the NPs size, distribution, shape and synthesis efficiency were assessed. The key parameters and interactions were highlighted and recipe of well-defined colloidal NPs were delivered. Impregnation of these NPs on different catalytic supports was performed using one pot and two-step syntheses. The effect of the immobilization process, parameter of synthesis, catalytic support, Pd content and scale of the synthesis on the NPs size and dispersion were studied. Finally, a kinetic study of the 1-octyne hydrogenation over four supported catalysts was performed using DOE. The 1-octyne concentration, hydrogen pressure and temperature were varied according to designed experiments: only 24 catalytic tests were performed to obtain robust kinetic expressions for the four catalysts. Thanks to these kinetic data, their performances were compared. This thesis offers a deeper analysis on the design of new Pd-based nanocatalysts for application in alkyne semi-hydrogenation reactions using practical and effective methodologies.
Yu, Bin. "Development of silver nanocatalyst for propylene selective oxidation reaction." Thesis, University of Oxford, 2018. http://ora.ox.ac.uk/objects/uuid:0f3f0556-bff1-4af1-bfe0-0e62b0425bff.
Повний текст джерелаHorecha, Marta, Elisabeth Kaul, Andriy Horechyy, and Manfred Stamm. "Polymer microcapsules loaded with Ag nanocatalyst as active microreactors." Royal Society of Chemistry, 2014. https://tud.qucosa.de/id/qucosa%3A36237.
Повний текст джерелаSCHLEXER, PHILOMENA DENIZ. "Nanostructures in Catalysis - Support Effects on Metal Clusters and Oxide Thin Films." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2017. http://hdl.handle.net/10281/158187.
Повний текст джерелаCatalysis has largely shaped society and will play a key part in the resolution of the energy and environment crisis we are facing in this century. The great advancements in the development of nanomaterials in the realm of nanotechnology have brought forth unforeseen possibilities also for the design of novel catalysts. The production and understanding of highly efficient catalysts based on nanostructured materials is the endeavor of the emerging field of nanocatalysis. In the last years, nanocatalysts have been studied extensively and progress in their large-scale fabrication has been demonstrated. Still, the technology is immature and further research is necessary to capitalize its full potential. Computational approaches are well suited to investigate the functioning of nanocatalysts and provide valuable atomistic insights. An accurate and efficient method is density functional theory (DFT). In this thesis, we explored the physical and chemical characteristics of supported metal clusters and oxide thin films using mainly DFT. These materials are of special interest in catalysis and many other applications, because of their unique features emerging from the nanostructuring. In particular, we investigated the geometry, the charge state, the cluster-support interaction, and the reactivity of sub-nanometer metal clusters supported on oxides. In a case study, we also addressed size-effects on larger metal nanoparticles. Regarding the supported clusters, we find that van-der-Waals dispersion forces are important for the correct description of the cluster-support interaction. Furthermore, we establish that defects and dopants present on the supporting oxide surface have a determining influence on the clusters, inherently affecting their reactivity. Also the modification of the clusters via alloying alters the metal-support interaction which can be exploited against cluster agglomeration. Nanostructuring of the oxide support engenders new material properties and in this context we examined the features of metal-supported oxide ultrathin films. Finally, we performed mechanistic studies contributing to elucidate the reaction mechanism of CO oxidation on Au/TiO2, as well as CO2 hydrogenation on Ru/TiO2 and Cu/TiO2.
Williams, Anna Rose. "Biogenic precious metal-based magnetic nanocatalyst for enhanced oxygen reduction." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6666/.
Повний текст джерелаWang, Siwen. "Orbital Level Understanding of Adsorbate-Surface Interactions in Metal Nanocatalysis." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/98923.
Повний текст джерелаDoctor of Philosophy
The interactions between reaction intermediates and catalysts should be neither too strong nor too weak for catalytic optimization. This Sabatiers principle arising from the scaling relations among the energetics of reacting species at geometrically similar sites, provides the conceptual basis for designing improved catalysts, but imposes volcano-type limitations on the attainable catalytic activity and selectivity. One of the greatest challenges faced by the catalysis community today is how to develop design strategies and ultimately predictive models of catalytic systems that could circumvent energy scaling relations. This work brings the quantum-chemical modeling and machine learning technique together and develops a novel stochastic modeling approach to rationally design the catalysts with desired properties and bridges our knowledge gap between the empirical kinetics and atomistic mechanisms of catalytic reactions.
Lopez, Sonia Garcia. "Novel synthesis of nanocatalysts for fuel cell applications." Thesis, University of Reading, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.577689.
Повний текст джерелаChan, Chun Wong Aaron. "Ultraselective nanocatalysts in fine chemical and pharmaceutical synthesis." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:866296af-5296-4d2e-8e52-6499dacaef0f.
Повний текст джерелаMallón, Pernia Laura. "Surface-functionalized and hybrid nanocatalysts for water splitting." Doctoral thesis, Universitat Autònoma de Barcelona, 2021. http://hdl.handle.net/10803/673661.
Повний текст джерелаUna solución para conseguir una fuente de energía libre de carbono es la fotoproducción de H2 mediante la división catalítica del agua (Water splitting, WS, Ecuación 1) utilizando la luz solar. 2H2O + hv --> 2H2 + O2 (Ecuación 1) WS es un proceso en el que el agua se oxida a dioxígeno en el ánodo (reacción de evolución del oxígeno, REO, Ecuación 2), constituyendo así la fuente de electrones para reducir los protones a H2 en el cátodo (reacción de evolución del hidrógeno, REH, Ecuación 3). 2H2O --> O2 + 4H+ + 4e- (Ecuación 2) 2H+ + 2e- --> H2 (Ecuación 3) El desarrollo de catalizadores de WS altamente activos y eficientes es esencial para la correcta cinética de estas dos semireacciones. Las nanopartículas (NPs) son verdaderos catalizadores potenciales debido a su alta estabilidad y relación superficie/volumen, exponiendo altas cantidades de sitios activos. En esta tesis doctoral se han sintetizado diferentes nanoelectrocatalizadores siguiendo el método organometálico, que resulta ventajoso para obtener nanomateriales de superficie limpia. Para entender los factores que afectan a la actividad electrocatalítica de los nanomateriales, se han realizado cálculos teóricos sobre la base de conceptos bien aceptados (energía libre de adsorción de hidrógeno, δGH*, y diagramas de volcán). Dado que los ligandos presentes en la superficie de las NPs metálicas pueden influir en la actividad electrocatalítica, se realizaron cálculos DFT para determinar los modos de coordinación más favorables de diferentes ligandos y obtener los valores de δGH*, obteniéndose correlaciones satisfactorias entre los datos experimentales y los de DFT. Diferentes estudios confirman que los soportes conductores de carbono mejoran la actividad electrocatalítica al restringir la agregación de los nanocatalizadores y mejorar la transferencia de electrones desde el nanocatalizador metálico al electrodo. En esta tesis doctoral se han utilizado dos materiales de carbono, el óxido de grafeno reducido (OGr) y las microfibras de carbono (FC), como soportes de NPs metálicas. Además, se ha estudiado el efecto del dopaje de N y P sobre el OGr en la REH, obteniendo un efecto sinérgico positivo entre heteroátomos y NPs de Ru. A diferencia del grafeno, las microfibras de carbono son más fáciles de manipular y pueden utilizarse directamente como electrodos. Así, se han sintetizado NPs de Ru y Co sobre dos microfibras diferentes, que difieren en la presencia o no de grupos -COOH en la superficie. Además, se han empleado dos metodologías diferentes, in situ y ex situ, para modificar la interfaz entre las NPs y el soporte de carbono mediante la adición de diferentes disolventes (THF o 1-heptanol) o ligandos (4-fenilpiridina, 4PP). Los resultados evidencian que una adecuada interacción entre las NPs y la superficie del soporte es clave para una mejor actividad catalítica, obteniéndose mejores resultados en los sistemas en los que tienen lugar interacciones π-π entre las estructuras Ru-4PP NPs/C o enlaces H entre las NPs de Co(OH)2 y -COOH en la FC. Otra estrategia prometedora es la adición de otro metal a una nanoestructura metálica, lo que conduce a efectos electrónicos beneficiosos al cambiar el entorno químico de los centros metálicos. En este sentido, se sintetizaron sistemas bimetálicos de Ru@Ni-espuma y NPs de RuCo. Se ha estudiado la influencia de diferentes porcentajes de dopaje de Ru en los sistemas de Ru@Ni-espuma sobre la actividad catalítica hacia la REO. Finalmente, se sintetizaron NPs de RuCo utilizando tres ligandos diferentes, 4’-(4-metilfenil)-2,2’:6’,2””-terpiridina, 4-PP y 1-heptanol, con el fin de determinar la influencia del ligando y de la ratio Ru/Co en el tamaño y la morfología de las NPs. Los estudios electrocatalíticos realizados abren una nueva puerta para explorar el interés de los nanocatalizadores bimetálicos en WS y la producción de hidrógeno.
One solution to achieve a carbon free energy source is the photoproduction of H2 by the catalytic water splitting (WS, Eq. 1) using sunlight. 2H2O + hv --> 2H2 + O2 (Eq. 1) WS is a process in which water is oxidized to dioxygen in the anode (oxygen evolution reaction, OER, Eq. 2), thus constituting the source of electrons to reduce protons to H2 in the cathode (hydrogen evolution reaction, HER, Eq. 3). 2H2O --> O2 + 4H+ + 4e- (Eq. 2) 2H+ + 2e- --> H2 (Eq. 3) Developing highly efficient and active WS catalysts is essential for the proper kinetics of these two reactions. Nanoparticles (NPs) are true potential catalysts due to their high stability and surface per volume ratio, exposing high amounts of active sites. In this PhD, different nanoelectrocatalysts have been synthesized by following the organometallic approach which is advantageous for obtaining clean-surface nanomaterials compared to other synthesis methodologies. To understand the factors affecting the electrocatalytic activity of the nanomaterials, theoretical DFT calculations have been performed on the basis of well accepted concepts (hydrogen adsorption free energy, δGH*, and volcano plots). Given that the ligands present on the surface of metal NPs can influence the electrocatalytic activity, DFT calculations were performed to determine the most favorable coordination modes of different ligands and to obtain the δGH* values of the resulting NPs. Successful correlations between experimental and DFT data have been obtained. Conductive C-based supports are known to enhance the electrocatalytic activity by restraining the aggregation of the nanocatalysts and improving the electron transfer from the metal nanocatalyst to the electrode. In this PhD, two different carbon materials, reduced graphene oxide (rGO) and carbon microfibers (CF) have been used as supports for metal NPs. Furthermore, the effect of N and P doping onto rGO has been studied towards the HER, obtaining a positive synergistic effect between the heteroatoms and Ru NPs. In contrast to graphene, CF are easier to handle and can be directly used as electrodes, thus avoiding the issues related to the NPs deposition onto macroscopic electrodes (GC, FTO). Thus, Ru and Co NPs have been synthesized on top of two different CF, differing in the presence or not of –COOH moieties onto the surface. Two different methodologies, in-situ and ex-situ, have been employed in order to tune the interface between the NPs and the C support by adding different solvents (THF or 1-heptanol) for Co NPs or ligands (4-phenylpyridine, 4PP) for Ru NPs. The results evidence that a proper interaction between the NPs and the support surface is key for an improved catalytic activity of the hybrid materials, obtaining better results in the systems where π-π interactions between Ru-4PP NPs/C structures or H-bonds between Co(OH)2 and COOH moieties in the CF take place. Another promising strategy is the addition of another metal onto a metallic nanostructure, leading to beneficial synergistic electronic effects by changing the chemical environment of the metal centers and decreasing the adsorption energy of the reactants. In this sense, bimetallic Ru@Ni-foam and RuCo NPs systems were synthesized. The influence on the catalytic activity towards OER of different percentages of Ru-doping in Ru@Ni-foam systems has been studied. Finally, RuCo bimetallic systems were synthesized by using three different ligands, 4’-(4-methylphenyl)-2,2’:6’,2”-terpyridine, 4-PP and 1-heptanol. The influence of the ligand and the Ru/Co metal ratio on the size and morphology of the NPs has been determined. Preliminary electrocatalytic tests have been performed, opening a new door to explore the interest of bimetallic nanocatalysts for the water-splitting and the production of hydrogen.
Universitat Autònoma de Barcelona. Programa de Doctorat en Química
Chiang, Wei-Hung. "Engineering Nanocatalysts for Selective Growth of Carbon Nanotubes." Cleveland, Ohio : Case Western Reserve University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1238692060.
Повний текст джерелаWang, Zhitao. "Development of new fibrous nanocatalysts for methane reforming." Thesis, Curtin University, 2015. http://hdl.handle.net/20.500.11937/795.
Повний текст джерелаGhirri, Alberto. "Sintesi e caratterizzazione di copolimeri fosforilati come stabilizzanti promotori in nanocatalisi." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/24358/.
Повний текст джерелаKim, Kyungduk. "Novel Nanocatalyst for the Selective Hydrogenation of Bio-Oil Model Compounds." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/16353.
Повний текст джерелаWeiner, Jonathan. "Colloidal Cu/ZnO nanocatalysts for CO2 hydrogenation to methanol." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/57498.
Повний текст джерелаArán-Ais, Rosa M. "Interfacial reactivity: model surfaces and tailored shape-controlled nanocatalysts." Doctoral thesis, Universidad de Alicante, 2016. http://hdl.handle.net/10045/70091.
Повний текст джерелаEdla, Raju. "Development of Cobalt based Nanocatalysts for Energy and Environment." Doctoral thesis, Università degli studi di Trento, 2014. https://hdl.handle.net/11572/368203.
Повний текст джерелаEdla, Raju. "Development of Cobalt based Nanocatalysts for Energy and Environment." Doctoral thesis, University of Trento, 2014. http://eprints-phd.biblio.unitn.it/1382/1/Raju_Thesis_PhD-2014.pdf.
Повний текст джерелаPopat, Yaksh Jyotindra. "Synthesis and characterization of nanocatalysts for applications in water purification and hydrogen production." Doctoral thesis, Università degli studi di Trento, 2019. http://hdl.handle.net/11572/246086.
Повний текст джерелаPopat, Yaksh Jyotindra. "Synthesis and characterization of nanocatalysts for applications in water purification and hydrogen production." Doctoral thesis, Università degli studi di Trento, 2019. http://hdl.handle.net/11572/246086.
Повний текст джерелаEl, Hakim Sara. "Photocatalytic and sonocatalytic reactions with Ti@TiO2 nanocatalyst for energy and environment." Thesis, Université de Montpellier (2022-….), 2022. http://www.theses.fr/2022UMONS047.
Повний текст джерелаCatalytic processes have been widely investigated as a promising approach for providing sustainable energy and clean water resources. Among such, photocatalytic and sonocatalytic processes have been adapted as successful methods for fulfilling those two objectives. The key factor to these processes is the use of active materials capable of eliminating harmful molecules from wastewater and transforming others into products of high-added value. Those integrated in photocatalytic processes must be active under solar light. Today’s major focus is the preparation of effective environmentally friendly photocatalysts using earth-abundant raw materials. One of the objectives of this thesis is to prepare noble-metal free Ti@TiO2 core-shell nanoparticles throughout the sonohydrothermal treatment of commercially available titanium nanoparticles in pure water. Structural, chemical and optical properties of the prepared core-shell nanoparticles have been carefully studied and further compared to those of the initial titanium nanoparticles. The activity of these particles has been tested for the thermal-assisted photocatalytic hydrogen production and the degradation of pollutants with either light or ultrasound. Hydrogen production with those particles was tested from aqueous solutions composed of different sacrificial reagents (alcohols, carboxylic acid/amine mixture, and glucose) under controlled temperatures and inert atmosphere. Improved photocatalytic activity of Ti@TiO2 nanoparticles with the increase of temperature (25 °C - 95 °C) was observed in all studied systems. The mechanism of the photocatalytic process has been discussed in terms of apparent activation energies and H/D kinetic isotope effects. In addition, comparative study of the activity of Ti@TiO2 and initial Ti0 nanoparticles towards the degradation of certain pollutants by light and by ultrasound was investigated herein. The presence of TiO2 shell on the surface of Ti nanoparticle s showed enhanced degradation of complexing molecules (EDTA) and organic dyes (RhB) under light in the presence of Ar/20% O2 while higher activity towards sonocatalytic EDTA degradation was observed with air-passivated Ti0 nanoparticles. At high-frequency ultrasound and in the presence of Ar/O2 atmosphere, efficient sonochemical degradation of Rhodamine B has been observed even without catalyst
Gupta, Kalyani S. "Nanocatalysts for the electrochemical reduction of carbon dioxide to fuels." Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10044005/.
Повний текст джерелаTomilin, S. V., and A. S. Yanovsky. "Formation of metal nanoparticles on nonmetal substrates for heterogeneous nanocatalysts." Thesis, Видавництво СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/20565.
Повний текст джерелаIn the present study the methods of synthesis and characterization of metal nanoparticles structures of a given size and surface topology on the non-metallic surfaces are described. The main application of such particles can be selective heterogeneous catalysis of chemical reactions or their usage as nucleus of growth centers for different nanostructures (tubes, whiskers, etc.). The formation of nanoparticles systems on the surface was carried out by two ways: by "thin cutoff plate" method and by vacuum annealing of ultrathin solid films. Metal was deposited on the substrate by thermal evaporation (deposition) in vacuum. Studies of the samples were carried out using the methods of Auger analysis and scanning electron microscopy. AES detects intense peaks of deposited metals with weak tungsten (the evaporator material), oxygen, carbon and the substrate material elements peaks in chemical composition of the films. The SEM studies reveal the presence of well-defined islet metallic structures on the samples obtained by both methods. For vacuum annealing method a clear correlation between annealing and obtained structures parameters is demonstrated. При цитировании документа, используйте ссылку http://essuir.sumdu.edu.ua/handle/123456789/20565
Komarneni, Mallikharjuna Rao. "Surface Chemistry Characterization of Hydrodesulfurization and Methanol Synthesis Model Nanocatalysts." Diss., North Dakota State University, 2012. https://hdl.handle.net/10365/26846.
Повний текст джерелаNSF Grant
DOE Grant
Duanmu, Chuansong. "EXPANDING APPLICATIONS OF IRON OXIDE NANOPARTICLES BY SURFACE FUCNTIONALIZATION: FROM MAGNETIC RESONANCE IMAGING TO NANO-CATALYSIS." OpenSIUC, 2009. https://opensiuc.lib.siu.edu/dissertations/110.
Повний текст джерелаTedsree, Karaked. "Study of structure and electronic effect aspects of nanocatalyst for formic acid electro-oxidation." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526429.
Повний текст джерелаKonnerth, Hannelore [Verfasser]. "Towards Selective Hydrogenation using Metal Nanocatalysts in Ionic Liquids / Hannelore Konnerth." München : Verlag Dr. Hut, 2018. http://d-nb.info/1155057562/34.
Повний текст джерелаLiu, Qiaoran. "Inorganic nanocatalysts for chemical decomposition of organic pollutants in contaminated water." Thesis, Curtin University, 2016. http://hdl.handle.net/20.500.11937/438.
Повний текст джерелаHe, Tianwei. "Computational discovery and design of nanocatalysts for high efficiency electrochemical reactions." Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/203969/1/Tianwei_He_Thesis.pdf.
Повний текст джерелаEsmaeili, E., A. M. Rashidi, Y. Mortazavi, A. A. Khodadadi, and M. Rashidzadeh. "The Role of Pore Structure of SMFs-based Pd Nanocatalysts in Deactivation Behavioral Pattern Upon Acetylene Hydrogenation Reaction." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35216.
Повний текст джерелаSatheesh, Srejith. "Fabrication and Validation of a Nano Engineered Glucose Powered Biofuel Cell." Thesis, KTH, Material- och nanofysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-162116.
Повний текст джерелаBertolucci, Elisa. "Green Synthesis of magnetic nanostructures suitable as recoverable nanocatalysts and conductive nanomaterials." Doctoral thesis, Scuola Normale Superiore, 2016. http://hdl.handle.net/11384/86197.
Повний текст джерелаAbrokwah, Richard Yeboah. "Development of Mesoporous Nanocatalysts for Production of Hydrogen and Fisher Tropsch Studies." Thesis, North Carolina Agricultural and Technical State University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10117803.
Повний текст джерелаThe primary aim of this study was to develop mesoporous nanocatalysts for (i) hydrogen production via steam reforming of methanol (SRM) in a tubular reactor, and (ii) syngas conversion to hydrocarbons via Fisher-Tropsch synthesis using silicon microchannel microreactors. The mesoporous catalysts for SRM were prepared by an optimized one-pot hydrothermal synthesis procedure. The catalysts were investigated for SRM activity in a packed bed tubular reactor using metals, namely, Cu, Co, Ni, Pd, Zn, and Sn. The metals were incorporated in different supports -MCM-41, SBA-15, CeO2, TiO2, and ZrO2 to investigate the influence of support on catalyst properties. A sharp contrast in catalyst performance was noticed depending on the type of support employed. For example, in SRM at 250 °C, Cu supported on amorphous silica SBA-15 and MCM-41 produced significantly less CO (< 7%) compared to other crystalline supports Cu-TiO2 and Cu/ZrO2 that showed high CO selectivity of ∼56% and ∼37%, respectively. Amongst all the metals studied for SRM activity using 1:3 methanol:water mole ratio at 250 °C, 10%Cu-MCM-41 showed the best performance with 68% methanol conversion, 100% H2 , ∼6 % CO, 94% CO2 selectivities, and no methane formation. Furthermore, 10%Cu-CeO2 yielded the lowest CO selectivity of 1.84% and the highest CO2 selectivity of ∼98% at 250 °C. Stability studies of the catalysts conducted for time-on-stream of 40 h at 300 °C revealed that Cu-MCM41 was the most stable and displayed consistent steady state conversion of ∼74%. Our results indicate that, although coking played an influential role in deactivation of most catalysts, thermal sintering and changes in MCM-41 structure can be responsible for the catalyst deactivation. For monomtetallic systems, the MCM-41 supported catalysts especially Pd and Sn showed appreciable hydrothermal stability under the synthesis and reaction conditions. While bimetallic Pd-Co-MCM-41 and Cu-Ni-MCM-41 catalysts produced more CO, Cu-Zn-MCM-41 and Cu-Sn-MCM-41exhibited better SRM activity, and produced much less CO and CH4. In spite of the improved the stability and dispersion of the monometallic active sites in the support, no noticeable synergistic activity was observed in terms of H2 and CO selectivities in the multimetallic catalysts. For the Fisher-Tropsch (F-T) studies, Co-TiO 2, Fe-TiO2 and Ru-TiO2 catalysts were prepared by the sol-gel method and coated on 116 microchannels (50μm wide x 100μm deep) of a Si-microreactor. The F-T process parameters such as temperature, pressure and flow rates were controlled by an in-house setup programmed by LabVIEW®. The effect of temperature on F-T activity in the range of 150 to 300°C was investigated at 1 atm, a flow rate of 6 ml/min and a constant H2:CO molar ratio of 2:1. In our initial studies at 220 °C, 12%Ru-TiO2 showed higher CO conversion of 74% and produced the highest C2-C4 hydrocarbon selectivity-of ∼11% ethane, 22% propane and ∼17% butane. The overall catalyst stability and performance was in the order of 12%Ru-TiO2>> 12%Fe-TiO2 > 12%Co-TiO2.
Vono, Lucas Lucchiari Ribeiro. "Design of nanocatalysts supported on magnetic nanocomposites containing silica, ceria and titania." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/46/46136/tde-17082016-082602/.
Повний текст джерелаA separação magnética tem recebido muita atenção como uma tecnologia robusta, altamente eficiente e rápida para recuperar catalisadores sólidos após uso em reações em fase líquida. Muitos estudos têm focado nas metodologias para a imobilização de espécies cataliticamente ativas, mas o desenvolvimento de suportes magnéticos tem se limitado a nanopartículas magnéticas revestidas com sílica, polímeros ou carbono. O desenvolvimento de nanocompósitos magnéticos com a incorporação de outros óxidos é muito desejável para ampliar a aplicação dessa tecnologia de separação em catálise. Nesse contexto, estudos da estabilidade térmica de magnetita revestida com sílica (Fe3O4@SiO2) foram realizados para avaliar a possibilidade de calcina-la sem perder as propriedades magnéticas do suporte. Uma etapa de calcinação é necessária para a deposição de diferentes óxidos na superfície da sílica, tais como céria e titânia. O Fe3O4@SiO2 calcinado preservou a morfologia \"core-shell\" e as propriedades magnéticas, porém apresentou um aumentou de seis vezes na área superficial. Novos suportes magnéticos foram desenvolvidos pela deposição de céria e titânia sobre magnetita previamente revestida com sílica. Nanocatalisadores magneticamente recuperáveis de Rh, Pd e Ru foram preparados. Os catalisadores foram utilizados na hidrogenação de ciclo-hexano, benzeno ou fenol e o principal objetivo dessa tese foi o estudo da influência de cada suporte na atividade catalítica. Os catalisadores foram preparados de duas formas diferentes: impregnação-redução e imobilização de nanopartículas (NPs) metálicas pré-formadas. As NPs coloidais foram preparadas pela redução de sais metálicos e, também, pela decomposição de complexos organometálicos. Catalisadores de ródio preparados pela impregnação de cloreto de ródio(III) e redução com H2 mostraram alguns problemas de reprodutibilidade, que foram superados utilizando NaBH4 ou hidrazina como agentes redutores. A preparação de catalisadores pela imobilização de NPs coloidais é uma alternativa interessante para obter catalisadores reprodutíveis e muito ativos. Nanopartículas de Pd, Rh e Ru foram preparadas a partir de organometálicos e imobilizadas em Fe3O4@SiO2 calcinada, Fe3O4@SiO2CeO2 e Fe3O4@SiO2TiO2. A eliminação do agente estabilizante torna os catalisadores mais ativos durante os reusos. O catalisador de Rh sobre o suporte de céria foi o catalisador mais ativo na hidrogenação de ciclohexeno (TOF 125000 h-1). O catalisador de Pd foi o catalisador mais seletivo para a hidrogenação de fenol em ciclo-hexanona, independente do suporte usado. A formação de ciclo-hexanol é favorecida pelo suporte de titânia e a hidrodesoxigenação para produzir ciclo-hexano ocorreu principalmente no suporte de sílica.
Yang, Yuan. "Graphene as a Solid-state Ligand for Palladium Catalyzed Cross-coupling Reactions." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5488.
Повний текст джерелаDelgado, Delgado Jorge Alonso. "Cobalt nanoparticles for Fischer-Tropsch Synthesis: from colloidal to well-defined supported nanocatalysts." Doctoral thesis, Universitat Rovira i Virgili, 2014. http://hdl.handle.net/10803/296440.
Повний текст джерелаLa presente tesis consistió en el diseño de nuevos nanocatalizadores de cobalto para la reacción de Fischer-Tropsch (FT). Nanoparticulas de cobalto fueron sintetizadas usando diferentes metodologías: reducción química usando borohidruro de sodio como agente reductor o descomposición térmica of compuestos organometálicos tales como Co2(CO)8. Las síntesis fueron realizadas en presencia de polímeros como agentes estabilizantes. Después de la síntesis, las nanopartículas de cobalto fueron aisladas, caracterizadas (usando TEM, HR-TEM, XRD, XPS, ICP, FTIR, TGA and RAMAN) y probadas en la reacción de Fischer-Tropsch en fase acuosa. Con la finalidad de comparar con catalizadores soportados clásicos, las nanopartículas de cobalto fueron también inmovilizadas en TiO2 y probadas en FT usando reactores de lecho fijo. En este estudio se observó que el desempeño (actividad y selectividad) de las nanopartículas de cobalto en ambos sistemas catalíticos dependió altamente de parámetros tales como el método de síntesis, el polímero estabilizante y el tamaño de partícula. Estas diferencias fueron atribuidas a variaciones en la estructura y composición of las nanopartículas que a su vez eran intrínsecas a cada parámetro de estudio
The present thesis consisted in the design of novel cobalt nanocatalysts for the Fishcer-Tropsch (FT) synthesis. Cobalt nanoparticles were synthesized using different methodologies: chemical reduction method using sodium borohydride as reducing agent or thermal decomposition of organometallic precursors such as Co2(CO)8. The syntheses were carried out under the presence of polymer stabilizers. After the synthesis, the cobalt nanoparticles were isolated, characterized (using TEM, HR-TEM, XRD, XPS, ICP, FTIR, TGA and RAMAN) and tested in the Aqueous Phase Fischer-Tropsch synthesis. For comparison purposes with classical supported catalysts, the cobalt nanoparticles were also immobilized on TiO2 and tested in FT using fixed bed reactors. In this study was observed that the catalytic performance (activity and selectivity) of the cobalt nanoparticles in both catalytic systems were highly dependent on parameters such as the synthetic methodology, the polymer stabilizer and the particle size. These differences were attributed to variations in the structure and composition of the NPs intrinsic to each parameter under study.
Deplanche, Kevin. "New nanocatalysts made by bacteria from metal solutions and recycling of metal waste." Thesis, University of Birmingham, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.532277.
Повний текст джерелаKolpin, Amy Louise. "A fundamental perspective on the effects of sulfur modification for transition metal nanocatalysts." Thesis, University of Oxford, 2014. https://ora.ox.ac.uk/objects/uuid:41d587f5-9704-4a3a-bb34-71bd0e91862b.
Повний текст джерелаPérez, Galera Juana María. "Impregnated Cobalt, Nickel, Copper and Palladium Oxides on Magnetite: Nanocatalysts for Organic Synthesis." Doctoral thesis, Universidad de Alicante, 2016. http://hdl.handle.net/10045/57586.
Повний текст джерелаWang, Yuxian. "Metal-based nanocatalysts for oxidative degradation of aqueous organic pollutants in contaminated water." Thesis, Curtin University, 2015. http://hdl.handle.net/20.500.11937/284.
Повний текст джерелаLiu, Yilin. "Magnetic nanocatalysts for oxidative decomposition of persistent organic pollutants (POPs) in contaminated water." Thesis, Curtin University, 2015. http://hdl.handle.net/20.500.11937/920.
Повний текст джерелаNarayanan, Radha. "Shape-Dependent Nanocatalysis and the Effect of Catalysis on the Shape and Size of Colloidal Metal Nanoparticles." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6878.
Повний текст джерелаPemberton, Barry Charles. "From Nanocontainer to Nanocatalyst: Mechanistic Studies of [2+2] Photodimerization of Coumarin Derivatives within Cucubit[8]URIL." Diss., North Dakota State University, 2013. https://hdl.handle.net/10365/26752.
Повний текст джерелаNational Science Foundation (NSF CAREER CHE- 0748525 and CHE- 1213880)
NSF ND-EPSCoR Seed Grant
NSF ND-EPSCoR Doctoral Research Fellowship
Zhou, Xiwen. "Study of shape effect of Pd promoted Ga2O3 nanocatalysts for methanol synthesis and utilization." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:ed45a832-d0d5-4f1d-8c14-aa54df10e8cb.
Повний текст джерела