Facile fabrication of hierarchical p-Ag2O/n-Nb2O5 heterojunction microspheres with enhanced visible-light photocatalytic activity.

Abstract

Constructing p–n heterojunction is an efficient strategy to improve the photocatalytic efficiency. Here, we report a hierarchical Ag2O/Nb2O5 heterojunction composite as a novel and efficient visible-light driven photocatalyst. Hierarchical Nb2O5 microspheres were prepared by a hydrothermal method, and then the in situ growth of Ag2O nanoparticles on their surfaces was realized by a simple deposition method. Structural and textural features of the Ag2O/Nb2O5 composites were investigated, revealing that Ag2O nanoparticles were well distributed on the surface of Nb2O5 microspheres. Photocatalytic degradation of rhodamine B (RhB) was significantly enhanced by Ag2O/Nb2O5 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 Nb2O5 microspheres and had excellent stability for at least 4 catalytic cycles. The superior photocatalytic performance of Ag2O/Nb2O5 photocatalyst can be ascribed to the hierarchical superstructure as well as the heterojunction between Ag2O and Nb2O5, which facilitated the separation of photogenerated charge carriers. This work has potential application in the future for solving environmental pollution.