Gao Rong, Zhang Jiangwei, Fan Guilan, Wang Xiaosong, Ding Fengyu, Guo Yan, Han Chenhui, Gao Yuliang, Shen Ao, Ding Junfang, Wu Limin, Gu Xiaojun
School of Chemistry and Chemical Engineering, Inner Mongolia Key Laboratory of Low Carbon Catalysis, Inner Mongolia University, Hohhot, 010021, China.
Department of Materials Science and State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai, 200433, China.
Angew Chem Int Ed Engl. 2025 Aug 25;64(35):e202505948. doi: 10.1002/anie.202505948. Epub 2025 Jul 24.
Electrochemical nitrate (NO ) reduction to ammonia (NH) under ambient conditions is promising to promote the artificial nitrogen cycling. Despite the development of transition metal-based catalysts, their incident in situ electrochemical reconstruction always leads to the ambiguity of veritable active sites and reaction mechanisms. In this work, we report an approach to encapsulate Ni@NiP particles with cationic Ni vacancies in hollow N-doped carbon nanofibers (designated Ni@Ni P@N-CNFs) for electrocatalytic NO reduction to NH and have investigated their surface reconstruction and reaction mechanisms using various in situ electrochemical characterizations and theoretical calculations. Specially, the regulation of cationic Ni vacancy concentration in the three defective Ni@Ni P@N-CNFs catalysts leads to the 3.92-fold NH yield rate difference at -0.2 V versus RHE. During the electrocatalytic reaction process, new amorphous Ni(OH) and NiOOH species form on the surface of Ni@Ni P@N-CNFs and the stable amorphous Ni(OH) species benefits the generation of more active hydrogen (*H) for hydrogenation with NO . This is further verified by the different reaction rate-determining steps on the pristine and reconstructed defective catalysts. Integration of the optimized defective catalyst as cathode into a stable aqueous Zn-NO-battery provides high power density and Faraday efficiency for NH.
在环境条件下，电化学硝酸盐（NO₃⁻）还原为氨（NH₃）有望促进人工氮循环。尽管基于过渡金属的催化剂有所发展，但其原位电化学重构往往导致真实活性位点和反应机理的不明确。在这项工作中，我们报道了一种在中空氮掺杂碳纳米纤维中封装具有阳离子镍空位的Ni@NiP颗粒（命名为Ni@NiP@N-CNFs）用于电催化NO₃⁻还原为NH₃的方法，并使用各种原位电化学表征和理论计算研究了它们的表面重构和反应机理。特别地，三种缺陷型Ni@NiP@N-CNFs催化剂中阳离子镍空位浓度的调节导致在相对于可逆氢电极（RHE）为-0.2 V时NH₃产率相差3.92倍。在电催化反应过程中，新的非晶态Ni(OH)₂和NiOOH物种在Ni@NiP@N-CNFs表面形成，稳定的非晶态Ni(OH)₂物种有利于生成更多用于与NO₃⁻氢化的活性氢（*H）。这在原始和重构的缺陷催化剂上不同的反应速率决定步骤中得到了进一步验证。将优化后的缺陷催化剂作为阴极集成到稳定的水系Zn-NO₃⁻电池中，可为NH₃提供高功率密度和法拉第效率。
