Type-II InSe/ g-C₃N₄ Heterostructure as a High-Efficiency Oxygen Evolution Reaction Catalyst for Photoelectrochemical...

We propose a conceptual design of InSe/ g-C₃N₄ van der Waals heterostructure to achieve highly efficient and spontaneous water splitting. InSe/ g-C₃N₄ possesses a direct band gap of 2.04 eV with type-II band alignment, which is beneficial to the separation of electrons and holes and exhibits proper valence and conduction-band positions for the redox reactions of H₂O. In addition, the adsorption of multiple water molecules and the changes of free energy on InSe/ g-C₃N₄ have been calculated to understand the oxygen evolution reaction (OER) process of water splitting. The free energies of reaction on three sides are all downhill, and the values of Δ G reduce to about -0.406 eV, indicating that the OER of water splitting is a thermodynamically permissible reaction without the aid of any other substance. Therefore, the water-splitting reaction could be thermodynamically continued using InSe/ g-C₃N₄ as a photocatalyst, which indicates that InSe/ g-C₃N₄ is an excellent candidate for photocatalyst or photoelectronic applications.