Gram‐level NH3 Electrosynthesis via NOx reduction on a Cu Activated Co Electrode

Abstract Ambient electrochemical ammonia (NH 3 ) synthesis is one promising alternative to the energy‐intensive Haber–Bosch route. However, the industrial requirement for the electrochemical NH 3 production with amperes current densities or gram‐level NH 3 yield remains a grand challenge. Herein, we report the high‐rate NH 3 production via NO 2 − reduction using the Cu activated Co electrode in a bipolar membrane (BPM) assemble electrolyser, wherein BPM maintains the ion balance and the liquid level of electrolyte. Benefited from the abundant Co sites and optimal structure, the target modified Co foam electrode delivers a current density of 2.64 A cm −2 with the Faradaic efficiency of 96.45 % and the high NH 3 yield rate of 279.44 mg h −1 cm −2 in H‐type cell using alkaline electrolyte. Combined with in situ experiments and theoretical calculations, we found that Cu optimizes the adsorption behavior of NO 2 − and facilitates the hydrogenation steps on Co sites toward a rapid NO 2 − reduction process. Importantly, this activated Co electrode affords a large NH 3 production up to 4.11 g h −1 in a homemade reactor, highlighting its large‐scale practical feasibility.