Microwave-assisted synthesis of TiO₂/WS₂ heterojunctions with enhanced photocatalytic activity

In this study, visible light-responsive photocatalysts based on TiO₂/WS₂ were prepared through a microwave-assisted hydrothermal process. These TiO₂/WS₂ composites featured a larger surface area and a wider range of optical absorption when compared with those of pure TiO₂. Ultraviolet photoelectron spectroscopy revealed that the energy band levels of the heterojunction between the TiO₂ and WS₂ components were compatible for charge transfer. Compared with pristine TiO₂, the photocatalytic activity of the TiO₂/WS₂ composites was enhanced significantly—the result of expanding the optical absorption spectrum into the visible region as well as decreasing the rate of recombination of the photogenerated electron/hole pairs. The visible photocatalytic activity of the as-prepared photocatalysts was evaluated through the degradation of methylene blue, using a white light emitting diode (LED) as the irradiation source. For the degradation under LED irradiation, the optimal content of WS₂ was 3.0 wt%. An examination of the TiO₂/WS₂ composites in human cells indicated that they were highly biocompatible; they did not affect the cellular proliferation or morphology, suggesting future applications in a biomedical capacity.