Theoretical insight into two-dimensional g-C6N6/InSe van der Waals Heterostructure: A promising visible-light photocatalyst

Abstract

The monolayer InSe has drawn extensive attention since it was firstly fabricated by exfoliation and encapsulation in 2017. In the paper the g-C6N6/InSe heterostructure is designed to achieve high-performance photocatalytic application, and it is unveiled that the g-C6N6/InSe is a typical type-II heterstructure. There is significant charge transferred from the g-C6N6 to the InSe in the heterostructure, which is demonstrated by charge density difference and Bader charge analysis. Moreover, the built-in electric field exists between the InSe layer and the g-C6N6 layer, which is favorable for the effective separation of photogenerated electron-hole pairs. In the meanwhile the binding energy shows that the g-C6N6/InSe is a van der Waals heterostructure, and the band gap for that can be effectively tuned by interfacial strain. In addition, it is manifested that absorption coefficient for the g-C6N6/InSe heterostructure in the visible-light range is enhanced remarkably as compared with individual InSe layer, which implies that constructing heterostructure is an effective way to improve optical performance. Furthermore, elementary reactions are also discussed in detail to evaluate photocatalytic activity. These results pave a path to deepen the understanding of the InSe-based heterostructure, which is useful to design and synthesize new water-splitting photocatalysts applied in the visible-light range.