Proton-Feeding Dual-N Claw Sites in a Copper-Covalent Organic Framework Promote Hydrogenation Kinetics for Electrocatalytic Nitrate Reduction

The electrocatalytic conversion of nitrate to ammonia offers a sustainable solution for both environmental remediation and green energy production, yet its complex proton-coupled electron transfer kinetics poses a grand challenge for catalyst design. Herein, we demonstrate a proton-feeding dual-nitrogen claw site (DNCS) within a copper-covalent organic framework (DNCS-CuCOF) that captures and supplies localized protons to nitrogenous intermediates on the Cu center, enabling efficient hydrogenation. Compared with pristine CuCOF, DNCS-CuCOF maintains structural stability and exhibits significantly enhanced electrocatalytic performance, achieving a high Faradaic efficiency of 94% and an ammonia yield of 10.6 mg h–1 mgcat–1 at −0.8 V vs RHE. In-situ characterizations and density functional theory calculations reveal that the DNCS, by supplying localized protons, accelerates proton transfer kinetics and reduces the energy barrier for the rate-limiting step (*NO → *NHO) via an N-site-assisted Langmuir–Hinshelwood mechanism. This work establishes a new design principle of atomically precise innovation-engineering by creating localized proton feeding, offering a versatile platform for advancing electrocatalysis.