The electrocatalytic reduction of nitrate waste into ammonia allows both the removal of nitrate contaminants and an alternative production of ammonia compared to the classical Haber–Bosch industrial process. Ammonia is useful in agriculture for manufacturing fertilizers, and as a reagent in pharmaceuticals, metallurgy, explosives, and the textile industry; ammonia is also an energy carrier in the automobile industry for next-generation fuel cells. Here we review the nitrate-to-ammonia conversion by electrocatalysis of industrial and agricultural waste, with focus on catalysts, reaction intermediates, side reactions, and reaction conditions. Electron transfer is facilitated by electrocatalysts with transition metals having occupied d-orbitals with similar energy levels to that of the nitrate lowest unoccupied molecular orbital. Green electro-conversion using carbon-based materials is also discussed. Results show nitrate conversion from 53 to 99.8% and ammonia selectivity from 70 to 97.4%.

与经典的 Haber-Bosch 工业过程相比，将硝酸盐废物电催化还原成氨既可以去除硝酸盐污染物，又可以替代生产氨。氨在农业中可用于制造化肥，并在制药、冶金、炸药和纺织工业中用作试剂；氨也是汽车行业下一代燃料电池的能源载体。在这里，我们回顾了工业和农业废物的电催化硝酸盐向氨的转化，重点关注催化剂、反应中间体、副反应和反应条件。过渡金属的电催化剂促进了电子转移，该过渡金属具有与硝酸盐最低未占分子轨道的能级相似的占据 d 轨道。还讨论了使用碳基材料的绿色电转换。结果显示硝酸盐转化率从 53% 到 99.8%，氨选择性从 70% 到 97.4%。