Boosting photoresposive ability of WO3–Bi2O3 nanocomposite 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–Bi2O3 composite nanorods were decorated with Bi particles by using the internal precipitation method. Structural analysis revealed that the Bi-metal-particle-functionalized WO3–Bi2O3 composite 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 WO3 nanorod template, the Bi–WO3–Bi2O3 composite 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–Bi2O3 composite 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–Bi2O3 nanorods could be tuned through appropriate reduction of the surface oxide layer; this is a promising approach to designing WO3–Bi2O3 nanorods with high photoactive performance.