Direct Electrochemical Ammonia Synthesis from Nitric Oxide.

NO removal from exhausted gas is necessary owing to its damage to environment. Meanwhile, the electrochemical ammonia synthesis (EAS) from N suffers from low reaction rate and Faradaic efficiency (FE). Now, an alternative route for ammonia synthesis is proposed from exhaust NO via electrocatalysis. DFT calculations indicate electrochemical NO reduction (NORR) is more active than N reduction (NRR). Via a descriptor-based approach, Cu was screened out to be the most active transition metal catalyst for NORR to NH owing to its moderate reactivity. Kinetic barrier calculations reveal NH is the most preferred product relative to H , N O, and N on Cu. Experimentally, a record-high EAS rate of 517.1 μmol cm  h and FE of 93.5 % were achieved at -0.9 V vs. RHE using a Cu foam electrode, exhibiting stable electrocatalytic performances with a 100 h run. This work provides an alternative strategy to EAS from exhaust NO, coupled with NO removal.