Vapor Deposition-Assisted Sulfurization Synthesis of S-doped WO3 Nanorods and Their Enhanced Photoactivity

Abstract

The hydrothermally derived WO3 nanorods were doped with sulfur through a simple vapor deposition-assisted sulfurization process at 550 °C. By changing the sulfurization duration from 1 to 10 min, the sulfur doping contents in the WO3 nanorods are 1.49–3.27 at%. After sulfurization treatments, the microstructural analysis reveals a phase transition from hexagonal to monoclinic structure for the WO3 nanorods. Furthermore, the sulfurization treatments result in a rugged surface feature of the WO3 nanorods. Compared with the pristine WO3 nanorods, sulfur-doping altered the energy band gap of the S-doped WO3 nanorods. The marked red shift of the absorption edge of the WO3 nanorods occurred after sulfurization treatments. Among various S-doped WO3 photocatalysts, the S-doped WO3 nanorods with an optimal S content of 2.26 at% exhibit superior photoelectrochemical (PEC) properties. The results show that the photoactivity of WO3 nanorods can be tuned by adjusting sulfurization duration, and the sulfur-doped WO3 nanorods with an appropriate sulfur content are feasible in applications of photoexcited devices with high efficiency.