First principles study on the type-II g-C6N6/PtSSe heterojunction: A potential photocatalyst for overall water splitting

Abstract

Constructing suitable van der Waals heterojunction is considered to be an efficient way to develop and design new multifunctional devices. In this work, DFT calculations have been preformed to investigate the stacking structures, electronic, optical as well as catalytic properties of vertical heterojunctions (g-C6N6/PtSSe) constructed from graphene-like C6N6 layer and PtSSe monolayer. It is predicted that Se-side contacted heterojunction (CN/SePtS) is a typical type-II semiconductor with band edges satisfying the conditions of overall water splitting, thus can be a potential photocatalyst. In addition, CN/SePtS also possesses good absorption ranging from ultraviolet to visible light regions. It is also found that strain engineering can further tune the electronic and optical properties of the heterojunction and even improve its visible light absorption. By considering the effect of optical driving force, CN/SePtS heterojunction with 4 % biaxial tensile strain is recommended to be a good candidate for overall water splitting photocatalyst. Our research can provide a guidance for designing new optoelectronic devices and photocatalysts based on g-C6N6/PtSSe vdW heterojunctions.