Junguang Tao

Effect of interfacial coupling on photocatalytic performance of large scale MoS2/TiO2 hetero-thin films

Interface electronic behavior of two-dimensional large scale MoS2/TiO2 hetero-thin films has been studied using photoemission spectroscopy. We show a clear experimental evidence for type II band alignment and upward band bending (∼0.55 eV) at the interface of this system. The valence band offset at monolayer MoS2/TiO2 interface was measured to be 2.15 eV, while the conduction band offset was 1.00 eV. The unique interface band positions introduce a strong build-in electric field for efficient electron-hole separation. In addition, thermal treatment results in better interfacial coupling and charge separation efficiency thus enhanced visible light photoactivity. Our results explicate the mechanism and emphasize its huge potential in visible light photocatalysis.

Interfacial engineering of MoS2/TiO2 hybrids for enhanced electrocatalytic hydrogen evolution reaction

Herein, we show that the synergistic effect between MoS2 and TiO2 enhances the hydrogen evolution reaction (HER) performance of their hybrids, which is tunable via interface engineering. Among several interfaces, MoS2/TiO2–H complexes exhibit the best HER activity. The observed Tafel slope of 66.9 mV/dec is well in range of previous literature reports, suggesting a Volmer–Heyrovsky mechanism. Enhanced activities were attributed to abundant active sites at the interfaces, as well as improved charge transfer efficiency. Our results emphasize the roles that interfaces play in enhancing the HER activities of MoS2-based heterogeneous catalysts.

Strain effect on electronic structure of two-dimensional γ-InSe nanosheets

We use density functional theory to calculate the electronic structure of monolayer and bilayer InSe nanosheets. The interlayer interaction is found to have a large effect on the s orbital distribution of In and Se atoms. The electronic properties of InSe change substantially under in-plane bi-axial strain, including the semiconductor-to-metal transition. Both van der Waals forces and the electron wave function overlap affect the electronic structure tunability in a delicate way. Aside from the band-nature change, the electron-transport ability is expected to be altered, which is important for InSe-based electronic devices.