1. 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
- Full Text
- View/download PDF