Time-dependent evolution of the Bi3.64Mo0.36O6.55/Bi2MoO6 heterostructure for enhanced photocatalytic activity via the interfacial hole migration

Abstract

Hierarchical Bi_3.64Mo_0.36O_6.55/Bi₂MoO₆ isotype heterostructures were successfully prepared via a one-pot hydrothermal route by using Bi₂O₃ porous nanospheres as a sacrificial template. By tuning the reaction time, the formation process of the Bi_3.64Mo_0.36O_6.55/Bi₂MoO₆ heterostructure involving Mo etching, phase transition and anisotropic growth was clearly identified. More importantly, the Bi_3.64Mo_0.36O_6.55/Bi₂MoO₆ heterostructure displayed remarkably enhanced photocatalytic activity for dye photodegradation than pure phase bismuth molybdate due to the efficient electron–hole separation and the interfacial photogenerated hole migration from inside the Bi_3.64Mo_0.36O_6.55 layer to outside the Bi₂MoO₆ layer. The opposite hole migration from the outer layer to the inner layer was also detected in Bi₂O₃/Bi₂WO₆ heterostructures, which resulted in the decrease of photocatalytic activity, further verifying the importance of hole migration direction. This work provides a novel route to fabricate heterostructured photocatalysts, as well as gives a strategy for mediating the charge migration to improve photocatalytic performance.