Cu-accelerated structural reconstruction to form CoMoO₄/Co(OH)₂/Cu tri-component for efficient synergistic catalytic...

Electrochemical nitrate reduction reaction (e-NO₃⁻RR) offers a dual solution for wastewater remediation and sustainable ammonia synthesis, yet its practical application is constrained by sluggish multi-proton/electron transfer kinetics. Herein, we engineer a self-reconfiguring heterometallic catalyst through in situ transformation of Cu-anchored CoMoO₄ nanosheets on nickel foam (CoMoO₄-Cu_1.5/NF). Under operational conditions, dynamic reconstruction generates a ternary CoMoO₄/Co(OH)₂/Cu heterostructure, achieving breakthrough e-NO₃⁻RR performance with an ammonia yield of 20.1 mg h⁻¹ cm⁻² and 98.5 % Faradaic efficiency at -0.2 V vs. RHE-surpassing all previously reported CoMoO₄-based catalysts. Through in-situ spectroscopy and density functional theory (DFT) calculations, the synergistic interactions among the components are elucidated: (1) Co(OH)₂ modulates intermediate adsorption and triggers water dissociation to supply reactive hydrogen (*H), (2) Cu nanoclusters selectively accelerate NO₃⁻-to-NO₂⁻ conversion while suppressing H₂ evolution through *H dimerization inhibition, and (3) CoMoO₄ drives NO₂⁻-to-NH₃ transformation. Further integration with glycerol oxidation reaction (GOR) establishes an energy-efficient bifunctional system that enhances overall catalytic efficiency compared to conventional oxygen evolution coupling. This work pioneers a heterometallic engineering strategy for designing adaptive electrocatalysts, advancing dual-functional electrocatalysis toward sustainable nitrogen and biomass valorization. ENVIRONMENTAL IMPLICATION: Nitrate pollution poses a significant environmental challenge globally. High nitrate levels can cause eutrophication in water bodies, threatening ecosystems and human health. Traditional ammonia synthesis methods are energy-intensive and produce substantial carbon emissions, conflicting with sustainable development goals. Electrocatalytic nitrate reduction (e-NO₃⁻RR) technology presents an innovative solution to these issues. In this study, we developed a self-reconstructing heterometallic catalyst by anchoring Cu onto CoMoO₄ nanosheets, creating a ternary CoMoO₄/Co(OH)₂/Cu heterostructure. This catalyst exhibits outstanding performance in e-NO₃⁻RR, outperforming previous CoMoO₄-based catalysts. This catalyst not only shows promise for mitigating nitrate pollution but also has the potential to enhance green ammonia synthesis and promote sustainable nitrogen cycling, significantly impacting environmental protection and energy sustainability.