Theoretical Investigation of Two-Dimensional FeC Structures with Surface Van Hove Singularity for Electrochemical Nitric Oxide Reduction Reaction.

The electrochemical nitric oxide reduction reaction (eNORR) is an efficient method for converting aqueous NO into NH. The pursuit of innovative electrocatalysts with enhanced activity, selectivity, durability, and cost-effectiveness for NORR remains a research focus. In this study, using particle swarm optimization (PSO) searches, density functional theory (DFT), and the constant-potential method (CPM), we predict two stable two-dimensional FeC monolayers, designated as α-FeC and β-FeC, as promising electrocatalysts for the NORR. Our results demonstrate that both α-FeC and β-FeC monolayers possess intrinsic metallicity with surface Van Hove singularity (SVHS), showing remarkable NORR catalytic performance. Additionally, the substantial disparity in adsorption free energies between NO and H atom at 0 V ensures the high selectivity of these novel FeC monolayers toward NORR. These findings not only contribute to the expanding family of two-dimensional transition metal carbides but also provide a new idea for the design of highly efficient NORR electrocatalysts.