Enhanced Photocatalytic Activity in Strain Engineered Janus WSSe Monolayers

The relevant fundamental properties of Janus WSSe monolayers to photocatalytic water-splitting performance are presented here and investigated using density functional theory. The Janus WSSe monolayer with a direct band gap of 1.75 eV is subjected to biaxial strain, and related optoelectronic properties are investigated. The effect of strain is reflected in band gap change from direct to indirect. Hydrogen evolution reaction (HER) is active all over, whereas oxygen evolution reaction (OER) is active only at 4% and 6% compressive strains. The red- and blue-shifts under tensile and compressive strains, respectively, substantiate possible control over exciton-phonon interaction making it suitable for the water-splitting application. Graphic Abstract: Upon being irradiated by sunlight with sufficient energy, the biaxially strained Janus WSSe monolayer complying with HER/OER requirement produces hydrogen gas along with oxygen as a secondary product.[Figure not available: see fulltext.]