Boosting Seawater Desalination by Ampere-Level Nitrate Electroreduction On Defect-Rich Ultrathin RuCu Alloy Nanostructures.

Abstract

Freshwater scarcity and nitrate pollution in water bodies are two growing environmental concerns. Developing green and sustainable techniques for simultaneous rapid freshwater production from seawater and efficient effluent treatment is crucial but remains challenging. Herein, we report the defect engineering of ultrathin alloy nanostructures for high-performance electrocatalytic nitrate reduction reaction (NO₃RR), which is further applied to drive seawater desalination. In specific, defect-rich RuCu nanoflowers (D-RuCu NFs) demonstrate superior selectivity toward ammonia electrosynthesis in neutral media and good stability for ampere-level operation in flow cells. In situ characterizations and theoretical calculations indicate that defective features of D-RuCu NFs possess more active sites for electrocatalysis and facilitate the nitrate adsorption and deoxygenation/hydrogenation processes. As a proof-of-concept application, the electrochemical NO₃RR driven seawater desalination delivers an ultrafast salt removal rate of 6033.05 µg cm^-2 min^-1, as well as achieves robust long-term stability of desalinating natural seawater to drinking water. This work offers an effective sustainable strategy for simultaneous nitrate conversion and seawater desalination, suggesting great potential for practical application within the water-energy nexus.