Ab initio high-throughput screening of transition metal double chalcogenide monolayers as highly efficient bifunctional catalysts for photochemical and photoelectrochemical water splitting

Abstract

Developing efficient bifunctional photocatalysts that can directly split water into hydrogen and oxygen under visible light irradiation has attracted tremendous attention because photocatalytic water splitting is a promising clean technology to harvest solar energy. Herein, we present a comprehensive high-throughput study on the stability and photocatalytic performance of transition metal double chalcogenide monolayers MXY (M = transition metal; X, Y = O, S, Se, Te; X ≠ Y) using first-principles calculations combined with polarizable continuum solvation models to describe solvent effects. Eleven out of 384 candidates exhibit appropriate bandgaps ranging from 1.99 to 2.71 eV, appropriate band edge positions matching water redox potentials, strong anisotropy of carrier mobilities, pronounced light absorption in the visible and ultraviolet regions, and high solar-to-hydrogen efficiency (up to 33%). Further reaction kinetics analysis shows that the photogenerated electrons and holes can readily drive water oxidation and hydrogen reduction half-reactions in PtSO and PtSeO monolayers under neutral conditions, where the overpotential is only 0.17, 0.13, 0.10, and 0.12 V for hydrogen evolution reactions in NiSO, NiSeO, PdTeO, and PtTeO monolayers, respectively. Our findings highlight transition metal double chalcogenides with high experimental feasibility as promising efficient bifunctional catalysts for photochemical and photoelectrochemical water splitting without sacrificial reagents or cocatalysts.