The electrocatalytic reduction of nitrate, a common contaminant in surface and ground water, to the harmless nitrogen gas is a promising technology that can be potentially energy efficient and environmentally friendly. The bottleneck hindering its large-scale implementation is mainly attributed to the unsatisfactory selectivity toward the final product N₂. To solve this challenge, a two-step strategy was applied here, in which the NO₃⁻ was first reduced to NH₄⁺ at the cathode, followed with a rapid non-electrochemical oxidation to N₂ by the ClO⁻ generated from anodic breakpoint chlorination. Note that the formation of ClO⁻ may be easily controlled and enhanced by the dosage of Cl⁻ ions, the overall nitrate removal efficiency for the above process was determined by its NO₃⁻ to NH₄⁺ activity. The high-performance copper-nickel alloys embedded mesoporous carbon electrocatalysts were therefore rationally designed, which exhibited a complete conversion of NO₃⁻ in the absence of Cl⁻, and furthermore, a 100% N₂ selectivity with the addition of Cl⁻. Using density functional theory calculations, it was verified that the incorporation of Ni atoms into Cu interface significantly enhanced the adsorption of *NHOH and *NH₂OH intermediates, lowering the barrier of *NOH hydrogenation to *NH₃ (NH₄⁺). Besides, the nitrogen-containing ordered mesoporous carbon support not only facilitated the synthesis of uniformly distributed CuNi nanoparticles (ca. 20 nm), but also ensured the sufficient mass and charge transfer, as well as the high durability.

将地表水和地下水中的常见污染物硝酸盐电催化还原为无害的氮气是一种很有前途的技术，具有潜在的节能和环保优势。阻碍其大规模实施的瓶颈主要归因于对最终产品N _{2 的}选择性不令人满意。为了解决这一挑战，这里采用了两步策略，其中 NO ₃ ^-首先在阴极还原为 NH ₄ ⁺，然后由阳极断点产生的 ClO ^-快速非电化学氧化为 N ₂氯化。请注意，ClO 的形成^-可以通过Cl ^-离子的剂量轻松控制和增强，上述过程的整体硝酸盐去除效率由其NO ₃ ^-到NH ₄ ^{+ 的}活性决定。因此，高性能铜镍合金嵌入介孔碳电催化剂的设计合理，在没有Cl ^-的情况下表现出NO ₃ ^-的完全转化，此外，在添加Cl ^-的情况下，N ₂选择性达到100% 。使用密度泛函理论计算，证实Ni原子掺入Cu界面显着增强了*NHOH和*NH ₂的吸附OH 中间体，降低了 *NOH 氢化成 *NH ₃ (NH ₄ ⁺ )的障碍。此外，含氮有序介孔碳载体不仅有利于合成均匀分布的CuNi纳米颗粒（约20 nm），而且保证了足够的质量和电荷转移，以及高耐久性。