Selective and Efficient Electrocatalytic Synthesis of Ammonia from Nitrate with Copper-Based Catalysts

The high stability and persistence of nitrates in water poses a serious threat to human health and ecosystems. To effectively reduce the nitrate content in wastewater, the electrochemical nitrate reduction reaction (e-NO₃RR) is widely recognized as an ideal treatment method due to its high reliability and efficiency. The selection of catalyst material plays a decisive role in e-NO₃RR performance. Copper-based catalysts, with their ease of acquisition, high activity, and selectivity for NH₃, have emerged as the most promising candidates for e-NO₃RR applications. In this paper, the mechanism of e-NO₃RR is first introduced. Then the relationship between structural properties and catalytic performance of copper-based catalysts is analyzed in detail from four aspects: nanomaterials, oxides, monoatomic, and bimetallic materials. Strategies for constructing efficient catalysts are discussed, including surface modulation, defect engineering, heteroatom doping, and coordination effects. Finally, the challenges and prospects of copper-based catalysts with high e-NO₃RR performance in practical applications are outlined.