Enhanced Visible-Light Photocatalytic Activity of Ball-Flower: TiO2/MoS2 Heterojunction

Due to the relatively large band gap and the rapid recombination of photogenerated electron-hole pairs (e(-)-h(+)) of pristine TiO2, its photocatalytic activity is severely limited. Molybdenum disulfide (MoS2) features a large specific surface area and abundant active sites, thereby serving as a favorable support for enhancing the photocatalytic activity of TiO2. In this study, a ball-flower TiO2/MoS2-80 heterojunction photocatalyst was prepared with a facile hydrothermal method. This heterojunction structure improves photocatalytic activity by enhancing visible light absorption, active site expansion, photogenerated charge separation, and transfer. Under visible light irradiation, the photocatalytic activity of TiO2/MoS2-80 heterojunction composites was evaluated for photocatalytic degradation of Rhodamine B (RhB). The results showed that TiO2/MoS2-80 heterojunction photocatalyst achieved a photocatalytic degradation efficiency of 90.1% for RhB in 1.5 h. The TiO2/MoS2-80 also exhibited the fastest degradation, with the highest kinetic rate of 2.48 x 10(-2) min(-1), which is 8.3 and 4.5 times higher than that of pristine MoS2 and TiO2. The free radical trapping experiments indicate that the primary active species in the photocatalytic process are h(+).