Although Co₃O₄-based non-noble metal electrodes have caused wide concern in electrochemical denitrification, the electrocatalytic activity and stability of these materials are still unsatisfied. In this work, a self-supported electrode (Co₃O₄/CF) was first fabricated via in-situ growth of needle-like Co₃O₄ on the cobalt foam (CF) and then used as cathode for electrochemical denitrification. The physicochemical and electrochemical characters of Co₃O₄/CF could be regulated by calcination temperature. Owing to the needle-like structure and the internal contact between Co₃O₄ and CF, the as-prepared Co₃O₄/CF-600 electrode exhibited excellent electrochemical performances for NO₃^– removal. The influences of current density, initial NO₃^– concentration, solution pH, and additive Cl^- concentration on electrochemical NO₃^– reduction were considered. A high NO₃^– removal efficiency (72.9%) and N₂ selectivity (96.2%) were achieved by Co₃O₄/CF-600 electrode under the optimum conditions: current density 5 mA/cm², Cl^- concentration 1500 mg/L and initial NO₃^– concentration 50 mg N/L. The cyclic voltammetry (CV) and electrochemical impedance spectra (EIS) confirmed that electrochemical denitrification was mainly realized via Co²⁺–Co³⁺–Co²⁺ redox process instead of H*-mediated indirect process. Moreover, the Co₃O₄/CF electrode material could keep its electrochemical properties even after 10 cycles.

尽管Co ₃ O ₄基非贵金属电极在电化学反硝化方面引起了广泛关注，但这些材料的电催化活性和稳定性仍不令人满意。在这项工作中，首先通过在钴泡沫 (CF) 上原位生长针状 Co ₃ O ₄制备自支撑电极 (Co ₃ O ₄ / CF)，然后将其用作电化学反硝化的阴极。Co ₃ O ₄ /CF的物理化学和电化学特性可以通过煅烧温度来调节。由于针状结构和 Co ₃ O之间的内部接触₄和CF，所制备的钴₃ ö ₄ / CF-600电极显示出优异的电化学性能为NO ₃ ^-的去除。考虑了电流密度、初始NO ₃ ^-浓度、溶液pH 和添加剂Cl ^-浓度对电化学NO ₃ ^-还原的影响。在最佳条件下，Co ₃ O ₄ /CF-600 电极实现了高 NO ₃ ^–去除效率（72.9%）和 N ₂选择性（96.2%）：电流密度 5 mA/cm ²，Cl ^-浓度 1500 mg/L 和初始 NO ₃ ^–浓度 50 mg N/L。循环伏安法（CV）和电化学阻抗谱（EIS）证实电化学反硝化主要通过Co ²⁺ –Co ³⁺ –Co ²⁺氧化还原过程而不是H*介导的间接过程实现。此外，Co ₃ O ₄ /CF 电极材料即使在 10 次循环后仍能保持其电化学性能。