Boosting Electroreduction Kinetics of Nitrogen to Ammonia via Tuning Electron Distribution of Single‐Atomic Iron Sites

Electrocatalytic nitrogen reduction reaction (NRR) plays a vital role for next‐generation electrochemical energy conversion technologies. However, the NRR kinetics is still limited by the sluggish hydrogenation process on noble‐metal‐free electrocatalyst. Herein, we report the rational design and synthesis of a hybrid catalyst with atomic iron sites anchored on a N,O‐doped porous carbon (FeSA‐NO‐C) matrix of an inverse opal structure, leading to a remarkably high NH3 yield rate of 31.9 μgNH3 h−1 mg−1cat. and Faradaic efficiency of 11.8 % at −0.4 V for NRR electrocatalysis, outperformed almost all previously reported atomically dispersed metal‐nitrogen‐carbon catalysts. Theoretical calculations revealed that the observed high NRR catalytic activity for the FeSA‐NO‐C catalyst stemmed mainly from the optimized charge‐transfer between the adjacent O and Fe atoms homogenously distributed on the porous carbon support, which could not only significantly facilitate the transportation of N2 and ions but also effectively decrease the binding energy between the isolated Fe atom and *N2 intermediate and the thermodynamic Gibbs free energy of the rate‐determining step (*N2 → *NNH). A single iron atom catalyst composed of atomically‐dispersed iron sites anchored on a N,O‐doped carbon matrix with an inverse opal structure is developed to accelerate nitrogen reduction reaction kinetics for efficient conversion of N2 into NH3.