Producing hydrogen, a clean and renewable resource, through photocatalytic water splitting using solar energy is a feasible and efficient route to resolve the energy and environment associated problems. The light harvest and electron-hole separation are keys to enhance the efficiency of solar energy utilization. We propose a new mechanism for photocatalytic water splitting that two-dimensional (2D) materials with the vertical intrinsic electric fields show great promise in inhibiting the electron-hole recombination and widening light absorption even to infrared light region. By using first-principles calculations, experimentally attainable 2D M2X3 (M = Al, Ga, In; X = S, Se, Te) family featuring vertical intrinsic electric fields are verified to be available photocatalysts for overall water splitting. Excitingly, In2Te3 is manifested to be an infrared-light driven photocatalyst, and its solar-to-hydrogen efficiency even achieves 32.1%. In addition, some kinds of 2D van der Waals heterojunctions are proved to be type-II or Z-scheme photocatalysts for water splitting with the advantage of facilitating the electron-hole separation.

Two-dimensional materials design for photocatalytic water splitting from a theoretical perspective

2019 Spring National Meeting

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