One-step synthesis of Cu(OH)2-Cu/Ni foam cathode for electrochemical reduction of nitrate

Nitrate (NO3-) pollution in natural water is severe and brings serious environmental and human health problems. With the rise of electrocatalytic NO3- reduction, highly reactive and selective electrodes are essential for the electrochemical reduction of NO3-. In this study, a one-step hydrothermal method was used to load Cu and Cu (OH)(2) on Ni foam (NF) (Cu(OH)(2)-Cu/NF) as a cathode. The system's unique design includes: Cu and Ni can promote the reduction of NO3- and the generation of active hydrogen atom (H*) as a reducing agent. Then, Cu(OH)(2) is beneficial to NO2- adsorption and promotes the reduction of NO2- intermediate. Finally, NH4+ is oxidized to N-2 by reactive chlorine generated at the anode. The Cu(OH)(2)-Cu/NF electrode exhibits a 91.5 % conversion of NO3--N in 90 min, which is 44 times higher than that of NF. Under 2000 mg/L Cl, NH4+ finally oxidizes to N-2 within 360 min, and N-2 selectivity is 95.60 %. In addition, the Cu(OH)(2)-Cu/NF electrode maintained an excellent electrochemical performance after 20 cycles. This study provided a new idea for designing efficient, stable, and inexpensive NO3- reduction electrodes.