Facile fabrication of hierarchical p-AgO/n-NbO heterojunction microspheres with enhanced visible-light photocatalytic activity.

Constructing p-n heterojunction is an efficient strategy to improve the photocatalytic efficiency. Here, we report a hierarchical AgO/NbO heterojunction composite as a novel and efficient visible-light driven photocatalyst. Hierarchical NbO microspheres were prepared by a hydrothermal method, and then the growth of AgO nanoparticles on their surfaces was realized by a simple deposition method. Structural and textural features of the AgO/NbO composites were investigated, revealing that AgO nanoparticles were well distributed on the surface of NbO microspheres. Photocatalytic degradation of rhodamine B (RhB) was significantly enhanced by AgO/NbO photocatalysts under visible light. The optimal Ag/Nb molar ratio was determined to be 0.15 : 1, which yielded a 21.8 times faster degradation rate constant than plain NbO microspheres and had excellent stability for at least 4 catalytic cycles. The superior photocatalytic performance of AgO/NbO photocatalyst can be ascribed to the hierarchical superstructure as well as the heterojunction between AgO and NbO, which facilitated the separation of photogenerated charge carriers. This work has potential application in the future for solving environmental pollution.