MX (M = Au, Ag; X = S, Se, Te) monolayers: Promising photocatalysts for oxygen evolution reaction with excellent light capture capability

Abstract

Oxygen evolution reaction (OER) is an important step in photocatalytic overall water splitting, and the search for photocatalytic OER catalysts with good light-harvesting ability has always been a hot topic. Herein, a new series of group-11 chalcogenides MX (M = Au, Ag; X = S, Se, Te) single layers are predicted by DFT calculations. The formation energy, phonon dispersion spectra and AIMD are calculated to certificate that MX monolayers are highly stable. MX monolayers are indirect bandgap semiconductors with bandgaps of 0.89–2.21 eV and their carrier mobilities [250.11–989.71 cm2/(V⋅s)]are also confirmed to be superior or comparable to that of MoS2 [∼200 cm2/(V⋅s)]. More particularly, their absorption of sunlight can reach the infrared light region, which far exceeds other commonly reported OER catalysts. Finally, it is confirmed that AuS, AuSe and AgS are potential photocatalytic OER agents, in which AuSe shows the best performance because it can spontaneously undergo OER under pH = 7 and light conditions. Moreover, we also hope that MX (M = Au, Ag; X = S, Se, Te) monolayers can be widely used in optoelectronic devices due to their excellent light capture performances.