Theoretical Investigation of Two-Dimensional FeC₄ Structures with Surface Van Hove Singularity for Electrochemical...

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.