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.