Electrocatalytic reduction of nitrate (NO₃^–) to ammonia (NH₃) in wastewater is a promising economic process for NH₃ synthesis. This work designed and prepared Au₁Cu (111) single-atom alloys with surface Cu vacancies (V_Cu-Au₁Cu SAAs), which exhibited superior NH₃ Faradaic efficiency (98.7%) with a production rate of 555 μg h^–1 cm^–2 at −0.2 V vs. RHE, while negligible activity decay was found after a durability test. Meanwhile, 97% of produced NH₃ can be recovered by a simple membrane distillation. Characterizations evidence that electron migration from Cu to Au atoms creates electron-deficient Cu active sites in V_Cu-Au₁Cu SAAs, which promote the generation of active hydrogen species (*H) that can readily hydrogenate NO₃^–. Theoretical calculation reveals that the bi-functional Cu sites not only promote the activation of water to produce *H but also lower the energy barrier of *NH₃ desorption from the catalyst surface.

将废水中的硝酸盐（NO ₃ ^–）电催化还原为氨（NH ₃）是一种很有前景的经济合成NH ₃工艺。本工作设计并制备了具有表面Cu空位(V _Cu -Au _{1 Cu SAA)的Au 1} Cu (111)单原子合金，其NH _{3法拉第效率(98.7%)具有555 μg h} ^-1的生产率。cm ^–2 at -0.2 V vs. RHE，而在耐久性测试后发现活性衰减可忽略不计。同时，产生的 NH _{3的 97%}可以通过简单的膜蒸馏回收。表征证据表明，电子从 Cu 到 Au 原子的迁移在 V _Cu -Au ₁ Cu SAA 中产生了缺电子的 Cu 活性位点，这促进了活性氢物质 (*H) 的产生，可以很容易地氢化 NO ₃ ^–。理论计算表明，双功能Cu位点不仅促进了水活化生成*H，而且降低了*NH ₃从催化剂表面解吸的能垒。