Selective electrocatalytic conversion of nitrogen oxides in wastewater: transforming pollutants into valuable nitrogen-containing compounds

Nitrate pollution in water bodies poses a significant threat to environmental sustainability and human health. Electrocatalytic nitrate reduction (NO₃RR) has surfaced as a promising green approach for tackling this pollution while also recovering valuable nitrogen-containing products, with ammonia being a prime example. This review outlines recent advances in the nitrate electroreduction reaction (NO₃RR), covering reaction mechanisms, catalyst design, and electrochemical C–N coupling. The complex reaction network of NO₃RR is governed by key intermediates such as *NO₂ and *NO, whose identification and the dynamic evolution of catalyst structures under realistic conditions rely heavily on advanced in situ characterization techniques. Rational catalyst design, including single-atom catalysts, alloy nanostructures, and defect-engineered materials, significantly enhances activity, selectivity, and stability by optimizing the adsorption of key intermediates. Electrochemical C–N coupling further enables the sustainable synthesis of high-value products including urea, amino acids, and oximes from nitrate and carbon sources, providing a green alternative to traditional energy-intensive industrial routes. Finally, current challenges and future perspectives are discussed, emphasizing the need for deeper mechanistic understanding, advanced industrial reactors, and a broader product portfolio. The integration of wastewater treatment, renewable energy utilization, and green chemical synthesis is expected to advance the practical application of electrochemical nitrogen conversion technologies.