One step in-situ grown Cu2O NPs on CF for efficient electrochemical nitrate reduction to ammonia

Rapid industrial growth and widespread fertilizer application have led to nitrate contamination in water, threatening ecosystems and human health. There is growing interest in developing electrocatalysts to convert nitrates into ammonia, enabling wastewater recycling and transforming harmful substances into valuable ammonia. In this study, we presented an eco-friendly, cost-effective electrocatalyst suitable for large-scale industrial production. It was designed specifically for the electrochemical reduction of NO 3 – to NH 3 (NO 3 − RR). Cu 2 O nanoparticles were synthesized on Cu foam through a simple one-step in situ growth approach. The conversion of Cu + , serving as the active site during NO 3 − RR, into nanoscale Cu had been investigated. Cu + sites initiated the conversion of nitrate to nitrite and subsequently facilitated the reduction of nitrite to ammonia while being transformed into nano-grained Cu. The newly generated Cu, with a larger specific surface area and lower charge transfer resistance, improved Faradaic efficiency (FE) for NH 3 in the NO 3 − RR process. As a result, an impressive nitrate removal rate of 100 % and a relatively high ammonia yield rate of 1514.67 µg h −1 cm −2 , along with a low residue of nitrite-N (0.21 ppm) can be achieved in solutions containing 100 ppm of nitrate-N.