Abstract Coupling the electrocatalytic NO x − reduction reaction (NO x − RR) with a more thermodynamically favorable dehydrogenation reaction offers an attractive route for sustainable ammonia synthesis. However, its efficiency is constrained by the slow kinetics of hydrogen atom transfer in both hydrogenation and dehydrogenation reactions. Herein, a strategy is presented to modulate hydrogen atom transfer kinetics at Pd─O─Co atomic interfaces, thereby enhancing the efficiencies of both NO x − RR and the hydrazine oxidation reaction (HzOR). The experimental investigations and theoretical calculations reveal that the rapid dissociation of H 2 O to form active hydrogen followed by efficient hydrogen spillover at the atomic interface, and the improved adsorption/activation of N 2 H 4 and accelerated hydrogen transfer along the interfacial Pd─O─Co bridge, result in reduced free energy changes in the hydrogenation of * NO and dehydrogenation of * N 2 H during NO x − RR and HzOR processes, respectively. The NO x − RR‐HzOR coupling system exhibits efficient NH 3 production alongside electricity generation. As a proof of concept, a direct hydrazine fuel cell is integrated with a NO x − RR‐HzOR unit to fabricate a self‐powered NH 3 production system. By utilizing ambient air as the nitrogen source, an efficient self‐powered gram‐scale NH 3 synthesis route is established, highlighting promising avenues for future industrial applications.