Copper-Driven Structural Reinforcement of CoFe LDH Enhances Nitrate Adsorption and Accelerates...

The electrochemical nitrate-to-ammonia reduction reaction (e-NO₃RR) attractively reconciles nitrate remediation with value-added NH₃ synthesis; yet, its practical application is hindered by an intricate eight-electron pathway, which results in mechanistic ambiguity and sluggish kinetics. Herein, atomic Cu is strategically implanted to regulate the electronic structure of the CoFe layered double hydroxides (LDH), thereby expanding the interlayer spacing, optimizing lattice parameters, and adjusting the Co/Fe coordination configuration. Copper-Driven structural reinforcement that propels nitrate-to-ammonia conversion, the optimized Cu-CoFe LDH catalyst delivers a Faradaic efficiency of 94% with an ammonia yield of 0.498 mmol h^-1 cm^-2 in e-NO₃RR. Consequently, the as-assembled Zn-nitrate battery achieves a power density of 5.07 mW cm^-2 with excellent cycling stability. In situ infrared spectra and differential electrochemical mass spectrometry characterizations combined with theoretical calculations reveal that Cu incorporation into CoFe LDH intensifies nitrate adsorption, accelerates the deoxygenation and hydrogenation of key intermediates, and suppresses the hydrogen evolution reaction. These optimized properties collectively elevate ammonia synthesis selectivity and enable efficient electrocatalytic nitrate reduction. This study implements a structural-reinforcement strategy that integrates electronic structure optimization with reaction kinetics enhancement, providing fresh insight into efficient electrocatalysts for NH₃ synthesis.