Defect chemistry of LaBO3 (B=Al, Mn or Co) perovskite-type oxides - Relevance to catalytic and transport behaviour

Computational techniques are used to model the defect chemistry of perovskite-structured LaBO3(B = Al, Mn or Co), which is of relevance to their use as oxidation catalysts and as oxygen-ion conductors. We consider a range of alkali-metal and alkaline-earth-metal dopant substitutions at the La site with oxygen vacancy compensation. Correlations with ion size are found with Sr predicted to have the most favourable solubility within all three systems, in accord with observation. We also calculate the energetics of oxidation in the doped oxide involving the creation of hole centres from the incorporation of molecular oxygen at O2- vacancy sites.