Oxygen nonstoichiometry of B-site doped LaCrO3

Recently, B-site doping in the perovskite-type oxides has often been carried out to control various properties. One of the perovskite-type oxides, doped LaCrO3, is the candidate for the interconnector for Solid Oxide Fuel Cells (SOFC). For its stability under reducing atmospheres, B-site doped LaCrO3 is also one of the candidates for the anode of SOFC. The oxygen nonstoichiometry, δ, in B-site doped LaCrO3-δ was measured as a function of oxygen partial pressure at 973 K to 1373 K. The observed values of δ were different by the different B-site dopants, and also different from those of A-site doped LaCrO3. It was shown that only 10 mol% of dopant in B-site drastically affects the redox property of LaCrO3. Defect model for B-site controlled LaCrO3 was interpreted by assuming the reaction, 2CrCrX + VO•• + 1/2O2(g)⇔2CrCr• + OOX.