Electrocatalytic NO Reduction to NH3: Theoretical Advances in Low-Dimensional Materials, Interfaces, and Microenvironments
Electrocatalytic nitric oxide reduction reaction (NORR) for ammonia synthesis has emerged as a research focus in artificial nitrogen fixation. Unlike previous reviews that primarily focus on experimental catalyst development, this work offers a comprehensive and systematic summary of recent theoretical progress in NORR, with special emphasis on low-dimensional materials. We connect four important areas: atomic-level design principles for active sites, emerging mechanistic ideas that go beyond conventional scaling relations, realistic simulations of the electrochemical microenvironment, and data-driven machine learning approaches for catalyst discovery. We begin by discussing the reaction mechanism, analyzing the orbital interactions that control NO activation and the thermodynamic and kinetic features of different reaction pathways. For active-site construction, we examine electronic synergy in single-atom and dual-atom catalysts, coordination microenvironment tuning, electronic structure modulation through doping and strain, and heterojunction interfaces that allow multi-degree-of-freedom regulation. To explore new mechanistic concepts, we introduce p-block element synergy, reverse activation, magnetic and spin control, and surface electronic singularities as strategies to overcome traditional scaling relations. Regarding the reaction microenvironment, we analyze how coverage, solvation, local pH, and applied potential jointly affect selectivity and activity. Finally, we summarize the role of machine learning in building descriptors and accelerating catalyst screening. This review aims to provide theoretical guidance for the rational design of efficient NORR electrocatalysts with high activity, selectivity, and long-term stability.