Nitrogen Reduction to Ammonia on Atomic‐Scale Active Sites under Mild Conditions

Ammonia is one of the most important chemicals and energy carriers. Currently, ammonia is industrially produced through the Haber–Bosch process under harsh conditions of high pressure and high temperature, which are energy consuming and environmentally unfriendly. Recently, nitrogen reduction to ammonia under ambient conditions has attracted intensive research interest, in which highly efficient catalysts are of great importance. In this review, recent theoretical and experimental progresses on novel heterogeneous catalysts with low atomicity for the nitrogen reduction reaction (NRR) under ambient conditions are highlighted. Reaction mechanisms for the NRR are first introduced. Then, advances in the synthesis and characterization of catalysts with single atom features are summarized, with a particular focus on the rational design of atomic catalysts for the NRR. Lastly, the critical challenges, possible solutions, and future perspectives in the research on NRR catalysis are presented. This review systematically presents the readers with the latest advances in this field, and more importantly, sheds light on the future development of NRR catalysis with the single atomic feature. Efficient catalysts are critical for the reduction of nitrogen to ammonia under ambient conditions. Downsizing active sites to the atomic scale provides abundant active centers with high homogeneity, low coordination, and unique electronic and structural features. These novel catalysts exhibit excellent catalytic performance for the nitrogen reduction reaction with high activity, selectivity, and stability, leading to sustainable production of ammonia.