Theoretical Investigation of Two-Dimensional FeC4 Structures with Surface Van Hove Singularity for Electrochemical Nitric Oxide Reduction Reaction

Abstract

The electrochemical nitric oxide reduction reaction (eNORR) is an efficient method for converting aqueous NO into NH₃. 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 FeC₄ monolayers, designated as α-FeC₄ and β-FeC₄, as promising electrocatalysts for the NORR. Our results demonstrate that both α-FeC₄ and β-FeC₄ 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 FeC₄ 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.