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1. Strain Field in Ultrasmall Gold Nanoparticles Supported on Cerium-Based Mixed Oxides. Key Influence of the Support Redox State

Author

Eloy del Rio, José A. Pérez-Omil, Susana Trasobares, Edward D. Boyes, José J. Calvino, Kenta Yoshida, Pratibha L. Gai, Miguel López-Haro, Jian-Min Zuo, Laboratoire d'Etude des Matériaux par Microscopie Avancée (LEMMA ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica (DCMIMQ), Universidad de Cádiz (UCA), Department of Chemistry [York, UK], University of York [York, UK], University of Illinois at Urbana-Champaign [Urbana], University of Illinois System, European Project: 312483,EC:FP7:INFRA,FP7-INFRASTRUCTURES-2012-1,ESTEEM 2(2012), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
chemistry.chemical_element, Nanotechnology, 02 engineering and technology, 010402 general chemistry, Catalytic-Properties, 01 natural sciences, Redox, Catalysis, Adsorption, Electrochemistry, General Materials Science, Spectroscopy, HREM Images, [PHYS]Physics [physics], Strain (chemistry), Chemistry, Fuel-Cell Applications, Surfaces and Interfaces, Hydrogen-Production, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, Cerium, Chemical engineering, Colloidal gold, Mixed oxide, Electron-Microscopy Techniques, Particle size, CO Oxidation, 0210 nano-technology, Zirconia Catalysts
Abstract

International audience; Using a method that combines experimental and simulated Aberration-Corrected High Resolution Electron Microscopy images with digital image processing and structure modeling, strain distribution maps within gold nanoparticles relevant to real powder type catalysts, i.e., smaller than 3 nm, and supported on a ceria-based mixed oxide have been determined. The influence of the reduction state of the support and particle size has been examined. In this respect, it has been proven that reduction even at low temperatures induces a much larger Compressive strain on the first 111 planes at the; interface. This increase in compression fully explains, in accordance with previous DFT calculations, the loss of CO adsorption capacity of the interface area previously reported for Au supported on ceria-based oxides.

Published
2016
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2. Reversibility of Pt-Skin and Pt-Skeleton Nanostructures in Acidic Media

Author

Pascale Bayle-Guillemaud, Miguel López-Haro, Yvonne Soldo-Olivier, Julien Durst, Laetitia Dubau, Laure Guétaz, Frédéric Maillard, Marian Chatenet, Laboratoire d'Electrochimie et de Physico-chimie des Matériaux et des Interfaces (LEPMI ), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National Polytechnique de Grenoble (INPG)-Institut de Chimie du CNRS (INC)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude des Matériaux par Microscopie Avancée (LEMMA ), Modélisation et Exploration des Matériaux (MEM), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica (DCMIMQ), Universidad de Cádiz (UCA), Institut de Chimie de Clermont-Ferrand (ICCF), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
[PHYS]Physics [physics], X-ray absorption spectroscopy, Nanostructure, Extended X-ray absorption fine structure, Chemistry, Alloy, Nanotechnology, engineering.material, Electrocatalyst, XANES, Overlayer, Chemical engineering, engineering, General Materials Science, Physical and Theoretical Chemistry, Chemical composition
Abstract

Following a well-defined series of acid and heat treatments on a benchmark Pt3Co/C sample, three different nanostructures of interest for the electrocatalysis of the oxygen reduction reaction were tailored. These nanostructures could be sorted into the "Pt-skin" structure, made of one pure Pt overlayer, and the "Pt-skeleton" structure, made of 2-3 Pt overlayers surrounding the Pt-Co alloy core. Using a unique combination of high-resolution aberration-corrected STEM-EELS, XRD, EXAFS, and XANES measurements, we provide atomically resolved pictures of these different nanostructures, including measurement of the Pt-shell thickness forming in acidic media and the resulting changes of the bulk and core chemical composition. It is shown that the Pt-skin is reverted toward the Pt-skeleton upon contact with acid electrolyte. This change in structure causes strong variations of the chemical composition.

Published
2015
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3. Critical Influence of Nanofaceting on the Preparation and Performance of Supported Gold Catalysts

Author

Ana B. Hungría, Xiaowei Chen, José A. Pérez-Omil, Sebastián E. Collins, José J. Calvino, Ginesa Blanco, Susana Fernandez-Garcia, Hanako Okuno, Miguel López-Haro, Miguel Tinoco, Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica (DCMIMQ), Universidad de Cádiz (UCA), Laboratoire d'Etude des Matériaux par Microscopie Avancée (LEMMA ), Modélisation et Exploration des Matériaux (MEM), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Universidad Nacional del Litoral [Santa Fe] (UNL), European Project: 312483,EC:FP7:INFRA,FP7-INFRASTRUCTURES-2012-1,ESTEEM 2(2012), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])

Subjects
Materials science, Físico-Química, Ciencia de los Polímeros, Electroquímica, Inorganic chemistry, Oxide, Nanoparticle, 02 engineering and technology, Transform Infrared-Spectroscopy, engineering.material, Type (model theory), 010402 general chemistry, 7. Clean energy, 01 natural sciences, Carbon-Dioxide, Deposition-Precipitation, Water-gas shift reaction, Catalysis, chemistry.chemical_compound, Adsorption, transmission electron microscopy, Ceria Nanocrystals, [PHYS]Physics [physics], CO Oxidation Activity, Ciencias Químicas, General Chemistry, Water-Gas Shift, 021001 nanoscience & nanotechnology, gold catalysis, ceria, 0104 chemical sciences, chemistry, Transmission electron microscopy, Defined Surface Planes, engineering, Nanoparticles, Noble metal, Transmission Electron Microscopy, Gold, Au/CeO2 Catalysts, 0210 nano-technology, Electron Tomography, CIENCIAS NATURALES Y EXACTAS
Abstract

A partial transformation of the {100} surfaces of ceria nanocubes into a set of nanometer-heighted, {111}- bounded, peaks was achieved by an oxidation treatment at 600°C. This particular type of surface nanostructuration allows the preparation of CeO2 nanoparticles in which {111} nanofacets contribute significantly to their surface crystallography. This transformation of the surface structure plays a key influence on the behavior of ceria as a support of gold catalysts. Thus, the appearance of well-developed {111}-nanofacets leads to a much higher efficiency in the usage of this noble metal in the synthesis of catalysts when prepared by the deposition-precipitation method. Moreover, gold catalysts supported on the surfacereconstructed oxide present an intrinsic (per gold surface atom) CO oxidation activity much higher than that of catalysts prepared on the nontreated oxide. Fil: Tinoco, Miguel. Universidad de Cadiz. Facultad de Ciencias; España Fil: Fernández García, Susana. Universidad de Cadiz. Facultad de Ciencias; España Fil: López Haro, Miguel. Universidad de Cadiz. Facultad de Ciencias; España Fil: Hungría, Ana B.. Universidad de Cadiz. Facultad de Ciencias; España Fil: Chen, Xiaowei. Universidad de Cadiz. Facultad de Ciencias; España Fil: Blanco, Ginesa. Universidad de Cadiz. Facultad de Ciencias; España Fil: Pérez Omil, Jose. Universidad de Cadiz. Facultad de Ciencias; España Fil: Collins, Sebastián Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); Argentina Fil: Okuno, Hanako. Grenoble Institute Of Technology; Francia Fil: Calvino, Jose J.. Universidad de Cadiz. Facultad de Ciencias; España

Published
2015
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4. Low-Lanthanide-Content CeO2/MgO Catalysts with Outstandingly Stable Oxygen Storage Capacities: An In-Depth Structural Characterization by Advanced STEM Techniques

Author

María Pilar Yeste, Miguel López-Haro, José M. Pintado, Juan J. Sanchez, Susana Trasobares, Pascale Bayle-Guillemaud, José J. Calvino, Ginesa Blanco, Ana B. Hungría, Miguel Tinoco, Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica (DCMIMQ), Universidad de Cádiz (UCA), Laboratoire d'Etude des Matériaux par Microscopie Avancée (LEMMA ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), European Project: 312483,EC:FP7:INFRA,FP7-INFRASTRUCTURES-2012-1,ESTEEM 2(2012), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
Lanthanide, Materials science, Magnesia, Hydrogen, Oxygen storage, Nanoparticle, chemistry.chemical_element, Nanotechnology, Catalyst Stability, Redox, Ceria Bilayer Nanostructures, Catalysis, Inorganic Chemistry, Ceria, Highly Dispersed, Physical and Theoretical Chemistry, Temperature-programmed reduction, Methane Coupling Reaction, Spectroscopy, Hydrogen production, Ultraviolet, Structure/Function Relationships, [PHYS]Physics [physics], Oxygen Storage Capacity, Organic Chemistry, Oxides, Temperature-Programmed Reduction, Hydrogen-Production, chemistry, Chemical engineering, Nanoparticles
Abstract

International audience; A novel CeO2/MgO catalyst with low ceria loading has been synthesized. This catalyst showed unique redox properties compared with conventional high and low surface area CeO2. Advanced (scanning) transmission electron microscopy techniques revealed the presence of a variety of highly dispersed ceria nanostructures: isolated CeOx entities, CeO2 clusters, as well as fairly small (

Published
2015
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5. Textural and phase stability of CexZr1−xO2 mixed oxides under high temperature oxidising conditions

Author

Michèle Pijolat, Gerardo Colón, Françoise Valdivieso, José J. Calvino, Richard T. Baker, Serafín Bernal, Laboratoire des Procédés en Milieux Granulaires (LPMG-EMSE), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Centre Sciences des Processus Industriels et Naturels (SPIN-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Département Procédés et évolution des systèmes avec solides (ProcESS-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-SPIN, Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica (DCMIMQ), Universidad de Cádiz (UCA), Universidad de Cádiz (Departamento de Ciencia de Materiales, Ingenieria Metallurgica y Quimica Inorganica, and Facultad de Ciencias

Subjects
Textural and phase stability, Chemistry, Sintering, Mineralogy, General Chemistry, Crystal structure, Catalysis, law.invention, Crystal, Chemical engineering, law, Specific surface area, Mixed oxide, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, Calcination, Texture (crystalline), Crystallite, Crystallographic changes, Sintering process
Abstract

International audience; The textural and structural changes in several Ce-Zr mixed oxides were studied. Changes in the crystal size and specific surface area upon calcination were followed at 1223 K over time. Different gas compositions (O2, CO2 and H2O) were employed during calcination in order to better understand the sintering process in the CexZr1−xO2 system. From SBET and mean crystal size (D) curves, we have tried to obtain the kinetic parameters. In order to do that, all curves were fitted using a mathematical expression which allows the derivative and then the kinetic rates for SBET decrease and D increase with calcination time to be obtained. It was also possible to correlate these rates with the Ce content of the mixed oxide, and to obtain information about the influence of composition on the sintering process at the surface and the crystalline structure of the mixed oxides. Complementary HREM/TEM data are also presented. With the help of this technique, it has been possible to elucidate the morphological and crystallographic changes in the crystallites upon calcination of the samples under oxidising atmospheres

Published
1999
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6. Redox behavior of CeO2-ZrO2 mixed oxides: II. Influence of redox treatments on low surface area catalysts

Author

Vidal, Hilario, Kaspar, Jan, Pijolat, Michèle, Colon, Gerardo, Bernal, Serafin, Cordon, Ana Maria, Perrichon, Vincent, Fally, Fabienne, Dipartimento di Scienze Chimiche (DSC), Università degli studi di Trieste, Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica (DCMIMQ), Universidad de Cádiz (UCA), Laboratoire des Procédés en Milieux Granulaires (LPMG-EMSE), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Centre Sciences des Processus Industriels et Naturels (SPIN-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Département Procédés et évolution des systèmes avec solides (ProcESS-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-SPIN, Instituto de Ciencia de Materiales de Sevilla (ICMSE), Universidad de Sevilla-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Laboratoire d'Application de la Chimie à l'Environnement (LACE), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Laboratoire Interdisciplinaire de Spectroscopie Electronique (LISE), Facultés Universitaires Notre Dame de la Paix (FUNDP), Università di Trieste, Universidad de Cádiz, Université Lyon 1 LACE UMR CNRS 5634, Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
Magnetic susceptibility, Oxygen storage capacity (OSC), Oxygen buffering capacity (OBC), Three-way catalysts, Raman spectroscopy, CeO2-ZrO2 mixed oxides, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, Structural and redox properties, X-ray diffraction
Abstract

International audience; Redox and textural/structural properties of low surface area (LS) ceria-zirconia mixed oxides with composition ranging from 0 to 85 mol% of ZrO2, have been studied using Raman spectroscopy, X-ray diffraction, textural characterization, magnetic susceptibility measurements, temperature-programmed reduction and oxidation and buffering measurements. Special attention was given to the effects of aging under redox conditions. Correlation between chemical composition, textural, structural and redox properties of the oxides is reported. Comparison with previously reported high surface area (HS) samples shows that in spite of the initial low surface area of the present samples (≈20 versus ≈100 m2g−1), the reduction occurs at fairly low temperatures when zirconium is incorporated into the CeO2 lattice. Remarkably, the favorable effects of the redox-aging on the reduction behavior are more pronounced in the present LS samples compared to the previously investigated HS ones. Raman and X-ray investigations revealed that important modifications of the structure take place as a consequence of the redox aging, leading to appreciable CeO2 segregation, which could suggest some correlation between these parameters.

Published
2001
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7. Influence of composition on the thermal stability of ceria-zirconia mixed oxides

Author

Pijolat, Michèle, Colon, Gerardo, Kenevey, Kester, Valdivieso, Françoise, Soustelle, Michel, Baker, Richard, Bernal, Serafin, Laboratoire des Procédés en Milieux Granulaires (LPMG-EMSE), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Centre Sciences des Processus Industriels et Naturels (SPIN-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Département Procédés et évolution des systèmes avec solides (ProcESS-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-SPIN, Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica (DCMIMQ), Universidad de Cádiz (UCA), F. Solymosi, J. Raskó, Universidad de Cádiz (Departamento de Ciencia de Materiales, Ingenieria Metallurgica y Quimica Inorganica, Facultad de Ciencias, and Toucas, Andrée-Aimée

Subjects
[SPI.GPROC] Engineering Sciences [physics]/Chemical and Process Engineering, Ceria-zirconia mixed oxides, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, CeO2-ZrO2, thermal stability, oxidising conditions, automotive exhaust gas treatment
Abstract

International audience; Ceria-zirconia mixed oxides are essential components in the three-way catalytic converters for automotive exhaust gas treatment and they must offer a good thermal stability in severe operating conditions. It is thus important to have a precise knowledge of the influence of the composition of the mixed oxide on the textural and structural properties of the catalytic materials. The behaviour of ceria-zirconia high surface area materials of nominal composition between CeO2 and Ce0.50Zr0.50O2 either bare or loaded with low ...

Published
2000

8. XPS study of Pt/CexZr1-xO2/Si composite systems

Author

Aaron Norman, Robert Sporken, Anouk Galtayries, Frédéric Mirabella, Keveney, K., Michèle Pijolat, Richard Baker, Serafin Bernal, Laboratoire Interdisciplinaire de Spectroscopie Electronique (LISE), Facultés Universitaires Notre Dame de la Paix (FUNDP), Centre Sciences des Processus Industriels et Naturels (SPIN-ENSMSE), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Département Procédés et évolution des systèmes avec solides (ProcESS-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-SPIN, Laboratoire des Procédés en Milieux Granulaires (LPMG-EMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica (DCMIMQ), Universidad de Cádiz (UCA), Univestité de Namur (LISE), Universidad de Cadiz (DCM), and Toucas, Andrée-Aimée

Subjects
CeZrO, [SPI.GPROC] Engineering Sciences [physics]/Chemical and Process Engineering, Zr4+, Pt clusters, XPS, ceria zirconia, systems, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering
Abstract

International audience; This work describes the study of a surface reduction of ceria zirconia mixed oxides (CeZrO) as either thin films or powders, both with and without Pt present. XPS was used to measure the composition of the surface and the oxidation states of all metals contained within the material. The thin film of CeZrO showed little reactivity towards the reducing conditions used. The size of the Pt clusters was also determined from the data. The Pt was found to always exist in the metallic state. The Zr4+ was not seen to change during all treatments. For the powder samples the CE4+ was readily reduced to approximately 60%. Pt was found to be initially oxidised with the % of metallic Pt increasing with reduction temperature. Again no change in the Zr was observed.

Published
2000

9. Thermal stability under different redox conditions of CexZr1-xO2 mixed oxides as potential TWC support

Author

Colon, Gerardo, Pijolat, Michèle, Valdivieso, Françoise, Baker, Richard, Bernal, Serafin, Laboratoire des Procédés en Milieux Granulaires (LPMG-EMSE), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Centre Sciences des Processus Industriels et Naturels (SPIN-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Département Procédés et évolution des systèmes avec solides (ProcESS-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-SPIN, Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica (DCMIMQ), Universidad de Cádiz (UCA), Universidad de Cádiz (Departamento de Ciencia de Materiales, Ingenieria Metallurgica y Quimica Inorganica, and Facultad de Ciencias

Subjects
Crystal size, Specific surface area, Oxidizing atmosphere, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, Thermal stability, Catalytic converters, Reducting atmosphere, Cerium-Zirconium Mixed Oxides
Abstract

International audience; It was studied the textural and structural changes in several Ce-Zr mixed oxides. The crystal size and specific surface area were followed upon calcination at 1223 K versus the time. It was also controlled the atmosphere composition. Gas mixture of O2, CO2 and H2O for oxidising condition and, H2 and H2O for reducing condition. Important differences have been found in the textural and structural features upon calcination in these two different atmospheres.

Published
1999
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10. Influence of high temperature treatments under net oxidizing and reducing conditions on the oxygen storage and buffering properties of a Ce0.68Zr0.32O2 mixed oxide

Author

Richard T. Baker, Serafín Bernal, Vincent Perrichon, Gerardo Colón, Hilario Vidal, Fabienne Fally, Ginesa Blanco, Michèle Pijolat, Jan Kašpar, Josémaria Pintado, Dipartimento di Scienze Chimiche (DSC), Università degli studi di Trieste, Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica (DCMIMQ), Universidad de Cádiz (UCA), Laboratoire des Procédés en Milieux Granulaires (LPMG-EMSE), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Centre Sciences des Processus Industriels et Naturels (SPIN-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Département Procédés et évolution des systèmes avec solides (ProcESS-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-SPIN, Laboratoire d'Application de la Chimie à l'Environnement (LACE), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Universidad de Cadiz, Università di Trieste, Université Lyon 1, Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
Redox behavior, Oxygen storage, Analytical chemistry, HREM, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Oxygen, Redox, Catalysis, symbols.namesake, chemistry.chemical_compound, Oxidizing agent, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, Oxygen storage capacity (OSC), Oxygen buffering capacity (OBC), General Chemistry, Aging treatment, 021001 nanoscience & nanotechnology, 0104 chemical sciences, chemistry, Chemical engineering, Magnetic balance, Ternary compound, TPR/TPO experiments, Raman spectroscopy, CeO2-ZrO2 mixed oxides, symbols, Mixed oxide, 0210 nano-technology
Abstract

International audience; TPR, TPO, O2 pulses and magnetic balance experiments have been performed to study the effect of two different aging treatments, in oxidizing atmosphere and in reducing conditions, on the redox behavior of a Ce0.68Zr0.32O2 mixed oxide. It has been observed that, although the samples resulting from both treatments have similar textural properties, their redox behavior is significantly different. In particular, aging in H2 improves the oxygen storage capacity (OSC) at low temperatures by decreasing the temperature at which reduction takes place. Also, the oxygen buffering capacity (OBC) is enhanced after aging under reducing conditions. In addition, the study of the re-oxidation of the samples reveals that the rate of the O2 uptake increases if compared with the fresh sample or that aged in air. High resolution electron microscopy and Raman spectroscopy data have also been used to obtain information on the possible origin of such effects.

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11. Surface and structural characterization of CexZr1-xO2 CEZIRENCAT mixed oxides as potential three-way catalyst promoters

Author

Hilario Vidal, Claude Binet, Gerardo Colón, Michèle Pijolat, Jan Kašpar, Marco Daturi, Elisabetta Finocchio, Françoise Valdivieso, Jean-Claude Lavalley, Richard T. Baker, Serafín Bernal, Centre Sciences des Processus Industriels et Naturels (SPIN-ENSMSE), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Département Procédés et évolution des systèmes avec solides (ProcESS-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-SPIN, Instituto de Ciencia de Materiales de Sevilla (ICMSE), Universidad de Sevilla-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica (DCMIMQ), Universidad de Cádiz (UCA), Dipartimento di Scienze Chimiche (DSC), Università degli studi di Trieste, Laboratoire catalyse et spectrochimie (LCS), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut de Chimie du CNRS (INC)-Université de Caen Normandie (UNICAEN), Normandie Université (NU), Istituto di Chimica, Facoltà di Ingegnieria (IdC), Università di Genova, Università di Trieste, Universidad de Cádiz, and Université Lyon 1 LACE UMR CNRS 5634

Subjects
Surface (mathematics), stability of CeZrMO, Mineralogy, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Catalysis, symbols.namesake, Phase (matter), Specific surface area, catalyst promoters, surface, CexZr1-xO2, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, Physical and Theoretical Chemistry, Fourier transform infrared spectroscopy, Porosity, structural, mixed oxides, Chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Characterization (materials science), Chemical engineering, symbols, 0210 nano-technology, Raman spectroscopy
Abstract

International audience; The textural and structural properties of high specific surface area (HS) CexZr1-xO2 mixed oxides (CeZrMO) and their modification upon thermal aging have been investigated. Results from BET area determination and complete porosity analysis, as well as high-resolution electron microscopy, XRD, Raman and FTIR spectroscopies are presented. Some relationships between the molar composition of the binary systems and their textural and structural properties are presented. In addition, it has been possible to propose an explanation for structural features of the mixed oxides (solid-solution structures and possible phase segregation) as a function of Ce content, a point of great interest for the knowledge of phase composition and stability of CeZrMO.

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