Enhanced photocatalytic activities under visible light of double-perovskite oxide semiconductor Ba 2 Tb(Bi, Sb)O 6 with mixed-valence

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 Ba _2 Tb(Bi _1-x Sb _x )O _6 ( 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 Ba _2 (Tb, Pr)(Bi, Sb)O _6 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.