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.