A computational study on strain dependent photocatalytic activity of Janus Ga-Al-X-Se (X = S and Se) monolayers

Abstract

The use of photocatalytic two-dimensional material for water splitting emerges as a significant technology in the field of green energy. Considering this viewpoint, the optoelectronic characteristics, photocatalytic, hydrogen, and oxygen evolution reactions (HER and OER) of the hexagonal GaAlXSe (X = S and Se) monolayers have been assessed in this research study with the help of density functional theory (DFT). The GaAlXSe (X = S and Se) monolayers are energetically, dynamically, and thermally stable. The GaAlSe2 and SGaAlSe monolayers are indirect semiconductors in nature. The absorption coefficient of both the monolayers is up to 105 cm−1. The suitable band alignments reveal that both the monolayers are appropriate for the photocatalytic application across all pH values at equilibrium. The strain dependent photocatalytic behavior of both the monolayers also have been evaluated. The nearly zero values of Gibbs free energies and the appropriate values of overpotentials signify efficient HER and OER catalytic activities of both the monolayers respectively.