Improved photocatalytic activity and durability of AgTaO3/AgBr heterojunction: The relevance of phase and electronic structure

Abstract

AgTaO₃/AgBr heterojunction was constructed for visible light driven photocatalytic purpose in order to investigate the relevance of phase conversion, electronic structure and photocatalytic properties. The result indicated that AgBr grafted on AgTaO₃ to form AgTaO₃/AgBr heterojunction gave intense visible light absorption, which exhibits highly enhanced photocatalytic performance than their individual counterpart. Theoretical and experimental investigation showed that the matched electronic structure between AgTaO₃ and AgBr induced an efficient transfer of photogenerated electrons from AgBr to AgTaO₃, leading to efficient charge separation and the subsequent improved photocatalytic activity. Partial AgBr converted to AgBr/Ag during the photocatalytic process, leading to the construction of ternary AgTaO₃/AgBr/Ag photocatalyst. Because of the surface plasmon resonance effect of Ag, the resulting AgTaO₃/AgBr/Ag exhibited wide range absorption and improved charge separation efficiency, which showed high durability and superior photocatalytic activity toward methyl orange degradation. On the basis of spin resonance measurement and trapping experiment, it is expected that photogenerated electrons, O₂⁻, and OH active species dominate the photodegradation of methyl orange.