Theoretical Investigation of Monolayer RhTeCl Semiconductors as Photocatalysts for Water Splitting

Photocatalytic water splitting, an environmentally friendly approach for producing hydrogen, is a feasible and efficient solution for the environmental and energy crisis. A major challenge for photocatalytic water splitting is searching for catalysts with suitable band gap and band alignment with promising electronic and optical properties. Herein, we predict a novel two-dimensional material, monolayer RhTeCl, which is potentially exfoliable from its bulk counterparts with a small cleavage energy (∼0.39 J/m2). Dynamical, thermal, and mechanical stabilities as well as suitable direct band gap (2.49 eV) and band edge positions qualify monolayer RhTeCl as a promising candidate for photocatalytic water splitting. High electron mobility and exciton binding energy further suppress the electron–hole recombination, and good light harvesting ability is presented with pronounced optical absorbance in the visible light and ultraviolet regions. In addition, the Gibbs free energy diagram shows that water splitting on monolayer RhTeCl can be effectively driven by solar energy. These features render monolayer RhTeCl semiconductors as promising photocatalysts for water splitting.