A DFT study of CuCl-XSe (X=Ga, In) vdW heterostructure as an efficient photocatalysts for hydrogen production

Abstract

The photocatalytic efficiency of monolayer materials can be greatly improved by constructing two-dimensional van der Waals heterostructures. In this work, the electronic properties and photocatalytic mechanism of the CuCl/XSe (X = In, Ga) vdW heterostructure with a stable structure are explored via the density functional theory. Our results indicate that the band gap of CuCl/InSe (1.241 eV) vdW heterostructure and CuCl/GaSe (1.334 eV) vdW heterostructure and large optical absorbance promote sunlight absorption and electron-hole pair generation. The built-in electric field formed at the interface accelerates the reorganization of photogenerated holes in XSe and photogenerated electrons in CuCl, which results in the photogenerated electrons and holes in the heterostructure accumulate in CB of XSe and VB of CuCl, respectively. The spatial separation of photoexcited electrons and holes prolongs the lifespan of carriers and enhances the photocatalytic efficiency of the CuCl/XSe vdW heterostructure. Meanwhile, the biaxial strain can effectively modify the band gaps. Finally, outstanding visible and near-infrared light absorption abilities mainly from ∼400 to around 1400 nm may guide the CuCl/XSe vdW heterojunction to a promises applications in photovoltaics.