Optimization of the cathode material for nitrate removal by a paired electrolysis process

► In this study, Cu70Ni30 has been identified as the most efficient cathode for nitrate reduction, with a selectivity of 100% toward ammonia. ► Also, Cu70Ni30 electrodes have a much better corrosion resistance than Cu and Cu90Ni10 in the presence of chloride, nitrate and ammonia. ► Paired electrolysis using Cu70Ni30 cathodes and Ti/IrO2 anodes allowed the conversion of nitrate to nitrogen from 620 ppm NO3− to less than 50 ppm NO3− with a power consumption as low as 20 kWh/kg NO3−, performances which are unequalled to date.