A-Site Deficient LaTiO2N Perovskites for Photocatalytic Water Oxidation

A-site defect engineering has been confirmed as an effective strategy for enhancing catalyst performance. Here, we develop a novel approach to synthesize A-site deficient perovskites by regulating alkali metal substitution and evaporation and further apply these materials for photocatalytic applications. Three representative perovskite oxides—La2Ti2O7, Na2La2Ti3O10, and Na0.5La0.5TiO3—were synthesized and then converted into perovskite oxynitrides with varying degrees of A-site defects (LaTiO2N, La0.67TiO2N, and La0.5TiO2N) through high-temperature ammonolysis. The photocatalytic water oxidation activity increased with the concentration of A-site defects, following the order: LaTiO2N < La0.67TiO2N < La0.5TiO2N, with a maximum enhancement of over 30 times. The performance boost was attributed to the facilitated interfacial electron transfer and improved charge separation caused by abundant A-site defects. These findings demonstrate that this strategy can successfully construct A-site deficient perovskites for highly efficient photocatalytic reactions, providing valuable insights for designing defect-engineered perovskite materials.