铜基催化剂因其低析氢活性和高氨选择性，在电催化硝酸盐还原氨领域受到了广泛关注。然而，稳定性差和活性低的问题限制了它的进一步应用。本研究工作中报道了一种负载在氮掺杂多孔碳上的Cu₂O/Cu异质结催化剂，并将其用于硝酸根还原反应。研究表明，载体氮掺杂多孔碳不仅可以有效提高催化剂的稳定性，还利于活性位点的暴露和分散。在−1.29 V（vs. RHE）的电位下，最大产氨速率为8.8 mg/(mg·h)，法拉第效率高达92.8%。高分辨率透射电子显微镜（HRTEM）和X射线衍射（XRD）结果表明，活性相的Cu₂O/Cu异质结的存在及异质结中Cu₂O和Cu的比例对催化剂性能具有重要的影响，这对构建高效的氨生产硝酸盐还原催化剂具有指导意义。

Copper-based catalysts have garnered wide attention in the field of electrocatalytic nitrate reduction for ammonia production due to their low hydrogen precipitation activity and high ammonia selectivity. However, they still face challenges pertaining of poor stability and low activity, which hinder their further application. Herein, we present a Cu₂O/Cu heterojunction catalyst supported on nitrogen-doped porous carbon for nitrate reduction. High resolution transmission electron microscopy (HRTEM) and X-ray Diffraction (XRD) results confirm the presence of Cu₂O/Cu heterojunctions, which serve as an active phase in catalysis. The nitrogen-doped porous carbon as a carrier not only enhances the catalyst’s stability, but also facilitates the exposure and dispersion of active sites. At −1.29 V (vs. RHE), the maximum production rate of ammonia reaches 8.8 mg/(mg·h) with a Faradaic efficiency of 92.8%. This study also elucidates the effect of Cu₂O-to-Cu ratio in the heterojunction on catalytic performance, thereby providing valuable insights for designing efficient nitrate reduction catalysts for ammonia production.