Atomically Dispersed Cu Sites on Dual‐Mesoporous N‐Doped Carbon for Efficient Ammonia Electrosynthesis from Nitrate

Abstract The industrial Haber‐Bosch process for ammonia synthesis is extremely important in modern society. However, it is energy intensive and leads to severe pollution, which has motivated eco‐friendly NH3 synthesis research. Electroreduction of contaminant nitrate ions back to NH3 is an effective complement but is still limited by low NH3 yields and nitrate‐to‐NH3 selectivities. In this study, the electrochemical nitrate reduction reaction (NTRR) is carried out over a single‐atom Cu catalyst. Atomically dispersed Cu sites anchored on dual‐mesoporous N‐doped carbon framework display excellent NTRR performance with NH3 production rate of 13.8 mol gcat−1 h−1 and NO3−‐to‐NH3 faradaic efficiency (FE) of 95.5 % at −1.0 V. Cu−N−C catalyst can sustain continuous 120 h NTRR test in the simulated NH3 synthesis scenarios with large current density (about 200 mA cm−2) and amplified volume of NO3− solution (9 times). Theoretical calculations reveal that atomically dispersed Cu1−N4 sites reduce the energy barrier of potential‐determining step in NTRR and promote the decomposition of primary intermediate in NO3−‐to‐N2 process. These findings provide a guideline for the rational design of highly active, selective and durable electrocatalysts for the NTRR.