Crystal face regulating MoS2/TiO2(001) heterostructure for high photocatalytic activity

Abstract

Semiconductor heterostructure is usually constructed to separate carriers, and the energy band structures of component semiconductors are mainly considered to achieve the separation. However, the interface of heterostructure also has a great influence on the transmission of carriers which is always neglected. Here, we employed {001} and {101} facets of anatase TiO2 as substrate to composite with two-dimension MoS2 and compared the photocatalytic activity. The results show that MoS2/TiO2(001) composite with optimal ratio demonstrates a large enhancement of photocatalytic activity as much as 3.4 times than that of pristine TiO2 nanosheets with exposed {001} facets. As compared, P25 with main exposed surface of anatase {101} facets was composited with MoS2, and the composite only exhibits 31% boost of photocatalytic activity than pristine P25. This contrast confirmed that {001} facets of anatase TiO2 are the key to construct carrier exchange heterostructure between MoS2 and TiO2 to enhance the photocatalytic activity. The HRTEM images show that the two-dimension MoS2 grown on the {001} facets of TiO2 nanosheets to show a face-to-face contact. This contact is an ideal transmission channel for photo-induce carriers with less scattering. Moreover, due to the higher valence band compared with {101} facets, the photo-induced holes will transfer to {001} facets and finally be extracted by MoS2 for photocatalysis degradation. The strategy that employs different crystal faces to regulate heterostructure interface can also be applied in other fields such as solar cell and electron device.