Triple Synergy Engineering via Metal-free Dual-Atom Incorporation for Self-sustaining Acidic Ammonia Electrosynthesis.

作者：Chuanzhen Feng, Kaiwen Bo, Jin Wan, Huijuan Zhang, Yu Wang · 发表于：Angewandte Chemie · 年份：2025 · DOI：10.1002/anie.202505211 · 研究领域：Medicine

Electrochemical nitrate reduction reaction (NO3RR) for ammonia synthesis under acidic conditions offers significant advantages, like direct fertilizer production and prevention of ammonia volatilization. However, three critical challenges persist: instability of metal-based catalysts, competition from the hydrogen evolution reaction (HER), and proton depletion leading to species imbalance. Here, we developed a novel metal-free heteronuclear diatomic-based catalyst that simultaneously addresses these challenges through atomic-level triple synergy engineering. Silicon-iodine dual-atom are precisely anchored on nickel oxide ultrathin nanosheets supported on carbon cloth (Si/I-NiO@CC) via a gradient-heating co-loading method. Si/I-NiO@CC establishes a self-sustaining catalytic system, achieving a remarkable Faradaic efficiency of 96.8% at -0.3 V vs. RHE and record-breaking operational stability of 420-h in acidic electrolyte, surpassing the performance of all reported acid NO3RR electrocatalysts to date. Advanced in situ spectroscopic characterization combined with electrochemical evaluation reveals the triple synergy mechanism: electron-deficient Niδ+ and oxygen vacancies generate abundant active sites while mitigating HER competition, iodine-mediated proton reservoir dynamically regulate H* coverage to maintain species balance, and covalent Si-O-Ni interfacial bonding inhibits metal leaching and stabilize the catalytic system. This work establishes a constructive guideline for ...