Quasi-linear dependence of cation filling on the photocatalysis of AxBO3-based tunnel compounds

Abstract

A series of A_xBO₃-based oxides, (A1)₄(A2)₂(A3)₄Nb₁₀O₃₀ (A1 = Sr, Ba; A2 = Na, K; A3 = □) as deficient perovskites, ATiO₃ (A = Mg, Ca, Sr, Ba) as ideal perovskites are prepared by solid-state reaction method, and investigated as novel tunnel photocatalysts. The efficiency exhibits a high dependence on the cation filling in the respective tunnels of these compounds. Generally, lower cation filling contributes to a higher activity. The cation filling is rationalized by the crystal packing factor (PF), the photocatalytic efficiency decreases quasi-linearly with PF. Moreover, the linear correlation also exists in the literature involving tunnel photocatalysts of Bi₂RNbO₇ (R = Y, rare earth element), MIn₂O₄ (M = Ca, Sr, Ba), ATaO₃ (A = Li, Na, K), etc. Such linear correlation of photocatalysis with the crystal structure has not been reported in the literature. The study of structure-modification by controlling cation-filling for improving activity sheds light on the mechanism of photocatalysis and on developing new high-performance photocatalysts.