Enhanced Nitric Oxide Electroreduction to Ammonia via Modulating Spin‐Polarization of Fe Single‐Atom Catalysts
Jialing Song, Zhiyi Wei, Lupeng Han, Zhenlin Wang, Chenghao Fan, Donglin Han, Chunwei Dong, Haiyan Duan, Xiyang Wang, Sam Fong Yau Li, Eslam M. Hamed, Ming Xie, Emiliano Cortés, Dengsong Zhang
Abstract
Abstract Electrochemical nitric oxide reduction (NORR) offers a sustainable pathway to ammonia (NH 3 ) while removing toxic NO from industrial emissions. However, high efficiency is hindered by the difficulty of synchronizing multi‐proton/electron transfers to accelerate NO hydrogenation and suppress competing hydrogen evolution. Here, an Fe single‐atom catalyst (FeSAC) is reported that achieves record NORR activity through spin‐state engineering. Using a top‐down electrospinning approach, self‐supported S,N‐doped carbon fiber films hosting Fe‐N 3 S 1 sites are fabricated. This catalyst delivers an NH 3 yield rate of 140.58 µmol h −1 cm −2 with a Faradaic efficiency of 96.28%, outperforming nearly all reported SACs. Mechanistic analysis reveals that sulfur doping induces a high‐spin Fe 3+ → low‐spin Fe 2+ transition, suppressing spin polarization, strengthening NO adsorption, and facilitating proton supply to accelerate hydrogenation. These results establish spin‐state modulation as a powerful paradigm for designing next‐generation single‐atom catalysts for complex multi‐proton/electron electrocatalytic transformations, such as the electrosynthesis of ammonia.