Computational Screening of Defective Group IVA Monochalcogenides as Efficient Catalysts for Hydrogen Evolution Reaction

Electrocatalysis has the potential to become a more sustainable approach to generate hydrogen as a clean energy source. Therefore, exploring stable, eco-friendly, and nonprecious catalysts for hydrogen evolution reaction (HER) is the key for the proposed hydrogen economy. In this work, by the means of density functional theory calculations, we systematically evaluate the stability, electrical conductivity, and HER activity to screen the best catalysts among the defective group IVA monochalcogenides MXs (M = Ge, Sn; X = S, Se). Our results reveal that M vacancy can trigger superior catalytic activities compared with the bare MXs basal plane. Especially, SnSe with Sn vacancies and GeSe with Ge vacancies with hydrogen adsorption free energy (Δ G H* ) ideally being near zero were screened out from the considered MXs. The defective SnSe can exhibit high HER activities at low defect concentrations and present excellent electrical conductivity. These performances are comparable to, or even better than, those of the currently used Pt for the HER. Furthermore, the detailed analysis of strain engineering and binding strength schematically unravel the mechanism of boosted hydrogen evolution. Our work introduces defective group IVA monochalcogenides as the promising HER catalysts for future energy applications and hold great promise to be realized experimentally.