Theoretical calculation of a TiO2-based photocatalyst in the field of water splitting: A review

Currently, energy and environmental problems are becoming more serious. The use of solar energy to split water and produce clean, renewable hydrogen as an energy source is a feasible and effective approach to solve these problems. As the most promising semiconductor material for photocatalytic water splitting, TiO2-based nanomaterials have received increasing attention from researchers in academia and industry in recent years. This review describes the research progress in the theoretical calculations of TiO2-based photocatalysts in water splitting. First, it briefly introduces some commonly used theoretical calculation methods, the crystal structure of TiO2 and its photocatalytic mechanism, and the principle of doping and heterojunction modification to improve the photocatalytic performance of TiO2. Subsequently, the adsorption state of water molecules with different coverages on the surface of TiO2, the rate-limiting steps of the splitting of water molecules on the surface of TiO2, and the transfer process of photogenerated current carriers at the interface between water molecules and TiO2 are analyzed. In addition, a brief review of research into the theoretical calculations of TiO2-based commercial photocatalysts in the field of water splitting is also provided. Finally, the calculation of TiO2-based photocatalytic water-splitting simulations is summarized, and possible future research and development directions are discussed.