Influence of the calcination temperature on the structure and reducibility of nanoceria obtained from crystalline Ce(OH)CO3 precursor

E. POGGIO; M. JOBBAGY; M. MORENO; M. LABORDE; F. MARIÑO; G. BARONETTI

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2011 vol. 36 p. 15899 - 15905

0360-3199

A high yield green method was developed for the preparation of reactive nanotextured ceria (CeO2). The preparation method is based on the oxidation of a crystalline Ce(OH)CO3 precursor that decompose at relative low temperature (ca. 250 ºC) yielding CeO2 nanocrystals initially rich in Ce3þ. After increasing calcination temperatures (in the range 350-650 ºC), PXRD analysis show a slight crystal growth after calcination temperatures up to 550ºC, however cell contraction in such case denotes the definitive oxidation of remnant Ce3þ centers. XPS results confirm Ce3þ fraction diminution as calcination temperature increases. TPR profiles of ceria samples show two reduction events being the low temperature one (at ca. 500 ºC) related to a surface process in which approximately only one cerium monolayer is involved. Catalytic activity tests for COPROX reaction were performed under differential reactor conditions to evaluate their activity in the temperature range 100-300 ºC. The optimum activity recorded for the sample calcined at 450ºC accounts for the compromise between oxide?s activation and surface preservation.