Electroreduction of Nitrite to Ammonia Over Ni1Ru Single‐Atom Alloys

Abstract Electroreduction of nitrite to ammonia (NO 2 RR) holds great promise for concurrently achieving efficient NH 3 electrosynthesis and wastewater purification. This study first develops Ni 1 Ru single‐atom alloys as an efficient and robust NO 2 RR catalyst. Extensive experiments and theoretical computations reveal that isolated Ni atoms electronically couple their adjacent Ru atoms to render Ni 1 Ru with high thermodynamic stability, boosted NO 2 − ‐to‐NH 3 hydrogenation energetics and suppressed hydrogen evolution. As a result, Ni 1 Ru assembled in a flow cell shows an exceptional NH 3 yield rate of 37.5 mg h −1 cm −2 with an NH 3 ‐Faradaic efficiency of 93.9% at a high current density of 312.3 mA cm −2 , representing one of the highest NO 2 RR performances ever reported.