Intrinsic Ni ⁰ –Ni ^δ+ Pairs in Anti‐Perovskite NiNNi ₃ Act as Hydrogen Radical Emitters for Cu Enabling Promoted Electrocatalytic Nitrate Reduction

Abstract Electrocatalytic nitrate reduction (NO 3 RR) enables ambient‐condition ammonia production, while ampere‐level application is still limited by the unsatisfactory efficiency due to the insufficient *H supply for rapid *NO hydrogenation. Herein, we tackled this challenge by constructing the NiNNi 3 /Cu heterostructure catalyst that utilizes the substantial electrostatic potential differences derived from the intrinsic Ni 0 –Ni δ+ pairs in anti‐perovskite NiNNi 3 to accelerate the O─H bond cleavage for *H generation, enhancing NO 3 RR. Consequently, the NiNNi 3 /Cu delivers 1.2 A cm −2 with 100 ± 0.7% Faradaic efficiency (FE) at ultralow +0.05 V RHE . The paired electrosynthesis by coupling NO 3 RR with formaldehyde oxidation yields 500 mA cm −2 at a low cell voltage of 0.8 V, with 95% NH 3 ‐FE and 90% formate‐FE. Importantly, industrial‐level application is further demonstrated by a flow cell with 25 cm 2 electrode that delivers 20 A, and produces 64 g NH 4 Cl for 20 h. This work provides a novel rationale for catalyst design that can boost *H density to accelerate hydrogenation kinetics for advanced electrosynthesis applications.