Catalytic properties of Ni/CeO2-Sm2O3 and Ni/CeO2-Y2O3 nanocomposites for intermediate temperatura Solid oxide fuell cells

M. BELLORA; R. BACANI; L.M. TOSCANI; R.J. PRADO; T. MARTINS; MARCIA C. A. FANTINI; S.A. LARRONDO.; D.G. LAMAS

Campinas

Encuentro; 24º Reunión Anual de Usuarios (RAU), Laboratorio Nacional de Luz Sincrotrón; 2014

LNLS

CeO2 based materials have received great attention due to their excellent catalytic properties for oxidation reactions. In the field of intermediate temperatura solid oxide fuel cells (IT SOFCs), CeO2 based anodes are subject to intense study because they have proven to exhibit excellent catalytic properties forboth partialoxidation of hydrocarbons in single chamber SOFCs and direct oxidation of hydrocarbons in conventional (two chamber)SOFCs. Besides, excellent performance in hydrogen fueled SOFCs has also been found. These excellent performance of CeO2 based anodes is related to the fact that they are mixed ionic/electronic conductors (MIECs) under reducing atmosphere and, therefore, fuel oxidation takes place on its entire surface, while it only occurs in the [anode/electrolyte/gas] triple phase boundaries for electronic conductors. It is important to point out that the number of active points for fuel oxidation should be dramatically increased in nanostructured, highspecific surfacearea MIECs. In this work, we present an in situ study of Ni/CeO2 Sm2O3 and Ni/CeO2 Y2O3 nanocomposites forIT SOFC anodes by DXAS technique. We studied the Ni K and Ce L3 edges under different operating conditions for H2 or CH4 oxidation. In this way, we monitor the Ni0/Ni2+ and Ce3+/Ce4+ ratios, which are strongly related to the catalytic properties of these materials. In all cases, the reactions were monitored with a mass spectrometer.