Boosting photoresposive ability of WO3-Bi2O3nanocomposite rods via annealing-induced intrinsic precipitation of nanosized Bi particles

Abstract

In this study, Bi-particle-functionalized tungsten trioxide-bismuth oxide (WO₃-Bi₂O₃) composite nanorods were prepared by integrating sputtering and hydrothermal syntheses with an appropriate postannealing procedure to induce Bi particle precipitation. Unlike other routes in which metal particle decoration is achieved externally, in this study, photoresponsive one-dimensional WO₃-Bi₂O₃composite nanorods were decorated with Bi particles by using the internal precipitation method. Structural analysis revealed that the Bi-metal-particle-functionalized WO₃-Bi₂O₃composite nanorods with particle size ranging from 5 to 10 nm were formed through hydrogen gas annealing at an optimal annealing temperature of 350 °C. Compared with the pristine WO₃nanorod template, the Bi-WO₃-Bi₂O₃composite nanorods exhibited higher photoresponsive performance, substantial photogenerated charge transfer ability, and efficient separation of photogenerated electron-hole pairs. The study results indicated that the Bi-WO₃-Bi₂O₃composite nanorods had superior decontamination ability and excellent stability toward RhB dye as compared with pristine WO₃. Moreover, the photogenerated charge separation and migration efficiencies of the WO₃-Bi₂O₃nanorods could be tuned through appropriate reduction of the surface oxide layer; this is a promising approach to designing WO₃-Bi₂O₃nanorods with high photoactive performance.

Keywords: annealing; metal particles; nancomposite rods; photoresponsive ability; precipitation.