The electronic structure underlying electrocatalysis of two‐dimensional materials

Abstract The understanding and development of advanced electrochemical catalysts have attracted intensive studies and achieved tremendous progress in the past decades. Two‐dimensional (2D) materials, such as doped graphene and atomically‐thin transition metal compounds, have shown great promise as electrocatalysts for various renewable energy conversion and storage reactions. Their further developments require improved understanding of the catalytic mechanisms at atomic level. Currently, most of the understandings are based on the formation free energies of the intermediates, which are determined by their binding strengths with the catalyst, usually calculated from density functional theory (DFT). These energies/binding strengths have been used as descriptor to describe the activity of many catalysts. However, it remains less explored why different catalysts have different binding strengths and what are the underlying factors controlling them, requiring studies going beyond atomic level to electronic level. This review aims to provide such links, focusing on 2D electrocatalysts for hydrogen evolution reaction (HER), oxygen reduction reaction/oxygen evolution reaction (ORR/OER), CO2 reduction reaction (CO2R) and nitrogen reduction reaction (NRR). We also discuss some of the significant issues that need to be addressed in DFT calculations, including the effects of varying charge and fixed potential of the catalyst, the passivation of active sites, and the solvation effects. This article is categorized under: Structure and Mechanism > Reaction Mechanisms and Catalysis Structure and Mechanism > Computational Materials Science