The electronic properties and enhanced photocatalytic mechanism of TiO2 hybridized with MoS2 sheet

• Key Words:TiO2/MoS2 composites; Charge density; Photocatalytic mechanism; DFT
• Abstract:In this work, first-principles calculation based on density functional theory (DFT) was used to explore the enhanced photocatalytic mechanism of TiO2 by combined with both pristine and defective monolayer MoS2. It was demonstrated that the combination of TiO2 with MoS2 was favorable thermodynamically. The charge densities between the interface of TiO2 and MoS2 were investigated to clarify the improved property of TiO2. Electrons migrated from TiO2 to MoS2 across the interface under irradiation, which caused the electrons accumulating on the MoS2 side and electrons depleting on the other TiO2 side. There appeared a built-in electric field in the interface between TiO2 and monolayer MoS2. And due to its presence, electrons and holes recombination was effectively suppressed, contributing to the enhanced photocatalytic performance of TiO2/MoS2. The electrons dispersed from highest occupied molecular orbital (HOMO) to lowest unoccupied molecular orbital (LUMO), promoting the separation of the electrons and holes. The efficient separation of photoexcited electrons and holes prolonged the lifetime of photoexcited carriers, which effectively improve the photocatalytic activity of TiO2. The theoretical study could provide credible evidence to understand the mechanism of enhanced photocatalytic activity of TiO2/MoS2.
• Volume:97
• Translation or Not:no