Wang Xiuyun, Peng Xuanbei, Chen Wei, Liu Guangyong, Zheng Anmin, Zheng Lirong, Ni Jun, Au Chak-Tong, Jiang Lilong
National Engineering Research Center of Chemical Fertilizer Catalyst, Fuzhou University, 350002, Fuzhou, Fujian, China.
National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, 430071, Wuhan, China.
Nat Commun. 2020 Jan 31;11(1):653. doi: 10.1038/s41467-020-14287-z.
The industrial synthesis of ammonia (NH) using iron-based Haber-Bosch catalyst requires harsh reaction conditions. Developing advanced catalysts that perform well at mild conditions (<400 °C, <2 MPa) for industrial application is a long-term goal. Here we report a Co-N-C catalyst with high NH synthesis rate that simultaneously exhibits dynamic and steady-state active sites. Our studies demonstrate that the atomically dispersed cobalt weakly coordinated with pyridine N reacts with surface H to produce NH via a chemical looping pathway. Pyrrolic N serves as an anchor to stabilize the single cobalt atom in the form of Co-N that facilitates N adsorption and step-by-step hydrogenation of N to *HNNH, *NH-NH and *NH-NH. Finally, NH is facilely generated via the breaking of the *NH-NH bond. With the co-existence of dynamic and steady-state single atom active sites, the Co-N-C catalyst circumvents the bottleneck of N dissociation, making the synthesis of NH at mild conditions possible.
使用铁基哈伯-博施法催化剂进行氨（NH₃）的工业合成需要苛刻的反应条件。开发在温和条件（<400 °C，<2 MPa）下表现良好的用于工业应用的先进催化剂是一个长期目标。在此，我们报道了一种具有高氨合成速率的Co-N-C催化剂，该催化剂同时展现出动态和稳态活性位点。我们的研究表明，与吡啶N弱配位的原子分散钴与表面H反应，通过化学循环途径生成NH₃。吡咯N作为锚定基团，以Co-N的形式稳定单个钴原子，这有利于N的吸附以及N逐步氢化为HNNH、NH-NH和NH-NH₂。最后，通过NH-NH₂键的断裂轻松生成NH₃。由于动态和稳态单原子活性位点的共存，Co-N-C催化剂规避了N解离的瓶颈，使得在温和条件下合成NH₃成为可能。
