Catalysis of the hydrogen oxidation reactions by Sr-doped LaMn1 - yCryO3 ± δ oxides

Sr-doped and Sr-free La1-xSrxMn1-yCryO3 (+/- delta) (LSMC, x(Sr) = 0-0.2, y(Cr) = 0.4-0.6) perovskite-type oxides were synthesized and evaluated as single phase anodes for use in intermediate temperature solid oxide fuel cell applications. Their thermo-chemical and chemical stabilities were investigated in hydrogen at high temperatures and correlated with their oxygen non-stoichiometry (3 +/- delta), determined by permanganate titration. The catalytic activity towards hydrogen oxidation was examined as a function of oxide sintering time, operating temperature, and the Sr and Cr contents, using a Pt mesh current collector. While all of the perovskite oxides studied here showed some irreversible performance degradation with time under both open circuit and anodically polarized conditions, La0.9Sr0.1Mn0.6Cr0.4O3.03 (LSMC9164), sintered at 1200 degrees C for 10 h, was found to be the most catalytically active and also the most stable. (C) 2011 Published by Elsevier B.V.