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You searched for subject:(Au CeO2). Showing records 1 – 3 of 3 total matches.

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1. Castanet, Uli. Contribution à l’étude des systèmes nanostructurés CeO2, Au et Au/CeO2 : Contribution to the study of nanostructured CeO2, Au, and Au/CeO2 systems.

Degree: Docteur es, Physico-Chimie de la Matière Condensée, 2017, Bordeaux

Les nanomatériaux sont de plus en plus utilisés dans de nombreusesapplications, que cela soit pour la catalyse, la coloration, l’optique, etc. Pour optimiser leurutilisation, il est nécessaire de mieux comprendre les réactions et interactions ayant lieu à ceséchelles. Cette thèse se propose d’essayer d’explorer les liens entre conditions de synthèse,morphologie de particules, et propriétés de celles-ci. En particulier, nous avons opté pourl’étude d’un matériau modèle : l’oxyde de cérium (IV). Les nanoparticules de CeO2 ont étéobtenues par voie de synthèse solvothermale assistée par chauffage micro-ondes. Lesmorphologies des nanoparticules de CeO2 étudiées ont été : les cubes, les octaèdres et lesbâtonnets, et nous avons essayé de fournir une explication à leur obtention par la voie desynthèse utilisée. De l’or a ensuite été déposé en surface des ces nanoparticules de CeO2 etétudié par une combinaison d’études par Microscopie Électronique en Transmission et demodélisations numériques.

Nanomaterials are more and more used in various situations, such as catalysis,color, optics, etc. To optimize their use, it is necessary to better understand reactions andinteractions taking place at these scales. This PhD thesis aims at exploring the links betweensynthesis conditions, particle morphology and their properties. In particular, we chose a tostudy a model-material: cerium (IV) oxide. CeO2 nanoparticles have been obtained bymicrowave-heating assisted solvothermal synthesis. Morphologies obtained and studied havebeen: cubes, octahedrons and rods. We tried to to give an explanation on how these synthesesallowed the formation of such morphologies. Gold has then be deposed on the surface of theseCeO2 nanoparticles, and studied by a combination of Transmission Electron Microscopystudies, and computer modelizations.

Advisors/Committee Members: Majimel, Jérôme (thesis director).

Subjects/Keywords: Nanoparticules; MET; Modélisation; Solvothermale assistée par chauffage micro-ondes; CeO2, Au; Au/CeO2; Nanoparticles; TEM; Computer modelling; Microwave-heating assisted solvothermal synthesis; CeO2, Au; Au/CeO2; 620.5

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APA (6th Edition):

Castanet, U. (2017). Contribution à l’étude des systèmes nanostructurés CeO2, Au et Au/CeO2 : Contribution to the study of nanostructured CeO2, Au, and Au/CeO2 systems. (Doctoral Dissertation). Bordeaux. Retrieved from http://www.theses.fr/2017BORD0600

Chicago Manual of Style (16th Edition):

Castanet, Uli. “Contribution à l’étude des systèmes nanostructurés CeO2, Au et Au/CeO2 : Contribution to the study of nanostructured CeO2, Au, and Au/CeO2 systems.” 2017. Doctoral Dissertation, Bordeaux. Accessed October 17, 2019. http://www.theses.fr/2017BORD0600.

MLA Handbook (7th Edition):

Castanet, Uli. “Contribution à l’étude des systèmes nanostructurés CeO2, Au et Au/CeO2 : Contribution to the study of nanostructured CeO2, Au, and Au/CeO2 systems.” 2017. Web. 17 Oct 2019.

Vancouver:

Castanet U. Contribution à l’étude des systèmes nanostructurés CeO2, Au et Au/CeO2 : Contribution to the study of nanostructured CeO2, Au, and Au/CeO2 systems. [Internet] [Doctoral dissertation]. Bordeaux; 2017. [cited 2019 Oct 17]. Available from: http://www.theses.fr/2017BORD0600.

Council of Science Editors:

Castanet U. Contribution à l’étude des systèmes nanostructurés CeO2, Au et Au/CeO2 : Contribution to the study of nanostructured CeO2, Au, and Au/CeO2 systems. [Doctoral Dissertation]. Bordeaux; 2017. Available from: http://www.theses.fr/2017BORD0600


Université de Bordeaux I

2. Feral-Martin, Cédric. Influence de la morphologie d’oxydes à base de cérium sur les relations (micro)structures/propriétés : Influence of the morphology of cerium-based oxide on the relation (micro) structure/properties.

Degree: Docteur es, Physico-Chimie de la Matière Condensée, 2010, Université de Bordeaux I

Les oxydes à base de Cérium, ont fait l’objet de nombreuses études ces dernières décennies et se sont révélés des matériaux de choix, dans le domaine de la catalyse hétérogène. L’objectif à l’heure actuelle, est donc d’accroître la réactivité de ces oxydes, tout en élargissant leur gamme de températures optimales d’utilisation. Dans ce contexte particulier, il semble possible de moduler les propriétés des oxydes à base de cérium en contrôlant la morphologie des cristallites. Ce travail de thèse a donc été consacré à la détermination, l’élaboration et à la caractérisation de matériaux oxydes à base de cérium de morphologies contrôlées. Nous avons tout d’abord déterminé cristallographiquement et thermodynamiquement les morphologies accessibles au système étudié puis par traitement hydrothermale assistée par chauffage micro-ondes nous avons synthétisé les dites morphologies. Après caractérisation de la réactivité par ATG et thermographie Infrarouge nous avons optimisé ces matériaux par un dopage extrinsèque tout d’abord (dépôt de métaux précieux), puis par un dopage intrinsèque ensuite (Yttrium et Fer). Enfin, l’obtention de morphologies non accessibles cristallographiquement nous a amené à approfondir le(s) processus de germination croissance de ces particules et la forte réactivité des matériaux dopés fer nous a poussé à une caractérisation fine de la microstructure de ces matériaux. Au final nous avons pu corréler l’influence de la morphologie des cristallites sur la réactivité propre de l’ensemble des familles de matériaux étudiés.

Recent decades, numerous studies on cerium-based oxides have been realized and have revealed that cerium-based oxides were materials of choice in the field of heterogeneous catalysis. The aim now is therefore to increase the reactivity of these oxides, while expanding their range of optimal temperatures of Use. In this particular context, it seems possible to modulate the properties of cerium-based oxides by controlling the morphology of the crystallites. This thesis has been devoted to the identification, development and characterization of materials based on cerium oxides of controlled morphology. We first determined possible morphologies for the studied system, by hydrothermal synthesis by micro-wave assisted heating we have synthesized these morphologies and we characterized reactivity of these materials by infrared thermography and TGA. We have optimized these materials first, by extrinsic doping (deposition of precious metals) and then by intrinsic doping (Yttrium and Iron). New morphologies have been synthesized so we have studied the processes of nucleation-growth set in. The high reactivity of iron-doped materials has led us to a detailed characterization of the microstructure of these materials. Finally correlation reactivity/morphologies of crystallites have been achieved.

Advisors/Committee Members: Demourgues, Alain (thesis director), Majimel, Jérôme (thesis director).

Subjects/Keywords: Morphologie; Oxydes à bases de Cérium; Au/CeO2; Traitement hydrothermale assistée par chauffage micro-onde; Propriétés de surface; Processus germination/croissance; Réactivité; Propriétés interfaces; Met; Morphology; Cerium-based oxides; Au/CeO2; Hydrothermal synthesis by microwave assisted heating; Surface properties; Tem; Process of germination/growth; Reactivity; Interface properties

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Feral-Martin, C. (2010). Influence de la morphologie d’oxydes à base de cérium sur les relations (micro)structures/propriétés : Influence of the morphology of cerium-based oxide on the relation (micro) structure/properties. (Doctoral Dissertation). Université de Bordeaux I. Retrieved from http://www.theses.fr/2010BOR14076

Chicago Manual of Style (16th Edition):

Feral-Martin, Cédric. “Influence de la morphologie d’oxydes à base de cérium sur les relations (micro)structures/propriétés : Influence of the morphology of cerium-based oxide on the relation (micro) structure/properties.” 2010. Doctoral Dissertation, Université de Bordeaux I. Accessed October 17, 2019. http://www.theses.fr/2010BOR14076.

MLA Handbook (7th Edition):

Feral-Martin, Cédric. “Influence de la morphologie d’oxydes à base de cérium sur les relations (micro)structures/propriétés : Influence of the morphology of cerium-based oxide on the relation (micro) structure/properties.” 2010. Web. 17 Oct 2019.

Vancouver:

Feral-Martin C. Influence de la morphologie d’oxydes à base de cérium sur les relations (micro)structures/propriétés : Influence of the morphology of cerium-based oxide on the relation (micro) structure/properties. [Internet] [Doctoral dissertation]. Université de Bordeaux I; 2010. [cited 2019 Oct 17]. Available from: http://www.theses.fr/2010BOR14076.

Council of Science Editors:

Feral-Martin C. Influence de la morphologie d’oxydes à base de cérium sur les relations (micro)structures/propriétés : Influence of the morphology of cerium-based oxide on the relation (micro) structure/properties. [Doctoral Dissertation]. Université de Bordeaux I; 2010. Available from: http://www.theses.fr/2010BOR14076

3. Revoy, Michelle. An Investigation of the Electronic and Catalytic Properties of Ceria Nanocubes.

Degree: 2013, University of Saskatchewan

The focus of this thesis was on the synthesis, characterization and application of ceria nanocubes. This thesis is divided into two main sections; the first section investigates the electronic properties of ceria nanocubes, and the second explores their catalytic applications towards alcohol oxidation reactions. The first project of this thesis consisted of the X-ray characterization of hydrothermally synthesized ceria nanocubes of various sizes. For the first time, the electronic properties of such nanocubes were systematically studied using high resolution XPS and XANES. It was found that the concentration of Ce3+ present within the nanocubes was independent of the particle size, as well as the Ce precursor used during synthesis. Throughout the analysis of the Ce 3d and 4d XPS spectra, it was observed that the surface of the ceria nanocube samples was undergoing photoreduction/damage over time. This damage was attributed to the samples’ exposure to high intensity X-ray radiation. This was confirmed through examination of the Ce M4,5- and N4,5-edge XANES spectra. From these results, it was clear that the concentration of Ce3+ on the surface of the ceria nanocubes was independent of particle size. This fact may become important when investigating their potential catalytic activity. The second project of this thesis concentrated on the analysis of the catalytic activity of a variety of CeO2, Au and Au/CeO2 catalysts towards the oxidation of benzyl alcohol. The low temperature oxidation reactions were studied using 1H NMR spectroscopy. It was observed that Au NPs, Au/bulk CeO2, and Au/CeO2 nanocubes in water and K2CO3 were active catalysts for this oxidation reaction at 60°C in both air and O2 (g) atmospheres. Surprisingly, however, the Au/bulk CeO2 and Au/CeO2 nanocube catalysts showed very similar activities. It was also found that ceria nanocubes alone, and Au25(SR)18/bulk CeO2 showed no activity for this reaction under similar conditions. It was determined that below a substrate to catalyst ratio of ~ 1500:1, the Au/CeO2 catalysts, which showed the highest activities, were mass-transport limited with respect to the O2 in the system. The turnover frequencies of the supported catalysts were approximately double those of the unsupported NPs. Furthermore, these reactions have indicated that activating Au25(SR)18/CeO2 for catalysis is a non-trivial task, and more work needs to be done to understand the activation of such clusters. Advisors/Committee Members: Grosvenor, Andrew, Scott, Robert, Paige, Matthew, Chang, Gap Soo.

Subjects/Keywords: Ceria nanocubes; XPS; XANES; Benzyl alcohol oxidation; Au/CeO2; Photoreduction

…62 Chapter 3 Catalytic Performance of Ceria NCs and Au/CeO2 Composites towards Benzyl… …66 3.2.4. Synthesis of Au/CeO2… …71 3.3.2.2. Au NPs and Au/CeO2… …78 3.3.3.3. Au/CeO2 Catalysts… …100 4.3.1. Characterization and Optimization of the Au/CeO2 Catalytic Systems… 

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Revoy, M. (2013). An Investigation of the Electronic and Catalytic Properties of Ceria Nanocubes. (Thesis). University of Saskatchewan. Retrieved from http://hdl.handle.net/10388/ETD-2013-10-1251

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Revoy, Michelle. “An Investigation of the Electronic and Catalytic Properties of Ceria Nanocubes.” 2013. Thesis, University of Saskatchewan. Accessed October 17, 2019. http://hdl.handle.net/10388/ETD-2013-10-1251.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Revoy, Michelle. “An Investigation of the Electronic and Catalytic Properties of Ceria Nanocubes.” 2013. Web. 17 Oct 2019.

Vancouver:

Revoy M. An Investigation of the Electronic and Catalytic Properties of Ceria Nanocubes. [Internet] [Thesis]. University of Saskatchewan; 2013. [cited 2019 Oct 17]. Available from: http://hdl.handle.net/10388/ETD-2013-10-1251.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Revoy M. An Investigation of the Electronic and Catalytic Properties of Ceria Nanocubes. [Thesis]. University of Saskatchewan; 2013. Available from: http://hdl.handle.net/10388/ETD-2013-10-1251

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.