Enhanced photocatalytic activities under visible light of double-perovskite oxide semiconductor Ba2Tb(Bi, Sb)O6 with mixed-valence

Abstract

In this study, we showed the effect of Sb substitution on lattice structures, physical properties and photocatalytic activities for the double-perovskite oxides with mixed valence. High quality powders of Ba2Tb(Bi1-xSbx)O6 (0.1 ≤ x≤ 1.0) were successfully synthesized using a citrate pyrolysis approach. Through partial substitution of Sb at Bi site of this compound, it was possible to design oxidative photocatalysts at lower x, and reduction-type ones at higher x. These findings are discussed on the basis of the conduction and valence band edge potentials of a series of Ba2(Tb, Pr)(Bi, Sb)O6 photocatalysts. The Sb substituted sample with the x = 0.6 composition predicted from the machine learning procedure exhibited the highest performance of methylene blue degradation, which is comparable to typical degradation rates for good perovskite catalysts.