Theoretical design of active Ga2O3 monolayer-based catalysts for electrocatalytic HER

Abstract

Electrocatalytic hydrogen evolution reaction (HER) offers a sustainable and clean route for hydrogen production. Developing a high-efficiency HER catalyst is extremely essential toward meeting future energy needs. Herein, the Sn-doped Ga₂O₃ monolayer, O-defected Ga₂O₃ monolayer, and Ru-adsorbed Ga₂O₃ monolayer with high electrocatalytic performances toward HER are reported (their H adsorption free energies are 0.169, 0.126 and 0.065 eV, respectively). The Sn-doped Ga₂O₃ monolayer follows the Volmer–Heyrovsky mechanism, and the O-defected Ga₂O₃ monolayer and Ru-adsorbed Ga₂O₃ monolayer are suitable for Volmer–Tafel mechanisms. The strain from −4% to 4% in the X- or Y-direction could linearly modulate the HER activities of the Sn-doped Ga₂O₃ monolayer and O-defected Ga₂O₃ monolayer. The Sn-doped Ga₂O₃ monolayer, O-defected Ga₂O₃ monolayer, and Ru-adsorbed Ga₂O₃ monolayer only manifest high HER catalytic activities in the strong acidic media. These phenomena can provide a rational approach to enhance the HER activity for Ga₂O₃ monolayer-based materials.