On the Reactivity and Structure of CeGa Mixed Oxides for Fuel Cell Applications

PAOLA QUAINO; LUCA SIFFERT; MONICA CALATAYUD; SEBASTIAN COLLINS; ADRIAN BONIVARDI

Nice

Congreso; The 61st Annual Meeting of the International Society of Electrochemistry. Electrochemistry from Biology to Physics; 2010

International Society of Electrochemistry - ISE

CeO2 is one of the most important active supports employed inreduction/oxidation catalytic processes. Nevertheless, its redox and acid-baseproperties may be easily tuned by doping ceria with other cations.The present work applies quantum chemical methods to build theoreticalmodels for Ce-Ga oxides to clarify and confirm experimental results obtained by two ofus. In this context, DFT calculations have been carried out for several Ce-Ga dopedbulk structures and (111)-surfaces to elucidate the effect of Ga and Oxygen vacancieson the structure and its reactivity.Preliminary results indicate that the surface is distorted with increasing theconcentration of Ga atoms. At low gallium concentration, a local effect in the Ce-Ga-Oenvironment is identified. This result is reflected in the structural studies: atomicpositions and the lattice parameter are modified in accordance with experimentalresults, and the local environment is characterized.In addition, the charge density analysis indicates that the presence of Gainduces a strong charge redistribution comparing with the pure CeO2 structure. Thismight lie at the origin of the unique catalytic properties of this mixed oxide.