The perovskite oxides have properties such as, bifunctional, phase transformation, structural stability, high catalytic performance, high thermal and hydrothermal properties, when substituting A3+ sites by X2+ cation, it will create oxygen vacancy, structural defects, and deficiency oxygen that is favorable in the field of catalysis. (A-site was responsible for structural stability, and B-site was responsible for catalytic performance).
But, when substituting cation by spinels oxides, that also creating oxygen vacancy can improve electron conductive of oxides, while these defects increase the activity like battery, electrocatalysis, and photocatalysis.
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about Spinals are best catalyst compare to Perovskites.