Multiple strategies of improving photocatalytic water splitting efficiency in 2D arsenic sesquichalcogenides.

Improving the solar-to-hydrogen efficiency has always been a significant topic in the field of photocatalysis. Based on first-principles calculations, herein, we propose multiple strategies to improve the photocatalytic properties of 2D arsenic sesquichalcogenides for full water splitting. The new configurations As 2 STe 2 and As 2 SeTe 2 monolayers, derived from the As 2 Te 3 monolayers by surface modification, are manifested to be typical infrared-light driven photocatalysts. Notably, under the built-in electric field, As 2 STe 2 and As 2 SeTe 2 monolayers can fulfil overall water splitting and the predicted solar-to-hydrogen efficiencies even reach up to 36.19% and 29.36%, respectively. The Gibbs free energy calculations indicate that the OER can be successfully driven under light irradiation. In addition, the overpotentials can provide most of the energy for HER when illuminated, especially for As 2 STe 2 with the . In addition, both As 2 S 3 and As 2 Se 3 monolayers are capable of satisfying the conditions for photocatalytic water splitting. Furthermore, the band gaps of As 2 Se 3 and As 2 S 3 can dramatically be narrowed by increasing the number of layers and doping, respectively. These findings provide a theoretical basis for As 2 X 3 monolayers to achieve efficient photocatalytic water splitting.