Facile fabrication of hierarchical p-Ag(2)O/n-Nb(2)O(5) 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 Ag(2)O/Nb(2)O(5) heterojunction composite as a novel and efficient visible-light driven photocatalyst. Hierarchical Nb(2)O(5) microspheres were prepared by a hydrothermal method, and then the in situ growth of Ag(2)O nanoparticles on their surfaces was realized by a simple deposition method. Structural and textural features of the Ag(2)O/Nb(2)O(5) composites were investigated, revealing that Ag(2)O nanoparticles were well distributed on the surface of Nb(2)O(5) microspheres. Photocatalytic degradation of rhodamine B (RhB) was significantly enhanced by Ag(2)O/Nb(2)O(5) 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 Nb(2)O(5) microspheres and had excellent stability for at least 4 catalytic cycles. The superior photocatalytic performance of Ag(2)O/Nb(2)O(5) photocatalyst can be ascribed to the hierarchical superstructure as well as the heterojunction between Ag(2)O and Nb(2)O(5), which facilitated the separation of photogenerated charge carriers. This work has potential application in the future for solving environmental pollution.