The InSe/g-CN van der Waals hybrid heterojunction as a photocatalyst for water splitting driven by visible light

Designing and developing the highly efficient photocatalysts is full of significance to achieve spontaneous photolysis water. In this work, using the first-principles calculations, we have performed a systematic theoretical study of water splitting photocatalytic activity of the InSe/g-CN heterojunction. It is concluded that the InSe/g-CN heterojunction is a typical type-II semiconductor, whose electrons and holes can be effectively separated. And the potential of the conduction band minimum (CBM) and valence band maximum (VBM) satisfy the requirements for photolysis water. Moreover, the changes of Gibbs free energy (ΔG) of the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) are calculated to investigate thermodynamic sustainability of photolysis water. The results show that when pH = 7, the potential driving force provided by the InSe/g-CN heterojunction can ensure the spontaneous progress of HER and OER. In addition, it is found that the solar conversion efficiency (ηS) of the InSe/g-CN heterojunction is up to 13.7%, which indicates it has broad commercial application prospects. Hence, the InSe/g-CN heterojunction is expected to be an excellent candidate for photolysis water.