Computational Screening of 2D Materials and Rational Design of Heterojunctions for Water Splitting Photocatalysts

As the energy crisis and environmental issues become increasingly serious, photocatalytic water splitting has received extensive attention as a promising method for the production of clean energy. However, available photocatalysts still have a long way to go. In light of the inherent advantages of 2D materials, reducing the thickness of nanosheets to monolayers is an effective strategy to achieve high photocatalytic activity. In this work, over 50 000 inorganic compounds from the Materials Project Database are screened, and 205 layered materials are obtained as candidates for water splitting photocatalysts. By exfoliating those layered materials and further examination, 36 kinds of 2D monolayers with validated stability and appropriate band edge position are achieved. To further enhance the photocatalytic activity, type-II van der Waals heterostructures are fabricated according to structure and band edge position, and show ideal band edge positions with effective spatial separation of electrons and holes. From layered materials to 2D mono-layers and then to type-II heterojunctions, a high-throughput computational materials design framework is proposed to gradually enhance the quantum efficiency and performance for photocatalytic water splitting. This screening algorithm exhibits excellent credibility and feasibility, and meanwhile provides substantial candidate catalysts for consequent experimental investigations on photocatalytic water splitting.