Electrochemical Reduction of Nitrate and Nitrite in Concentrated Sodium Hydroxide at Platinum and Nickel Electrodes

The electrochemical reduction of nitrite and nitrate in concentrated sodium hydroxide solution has been studied as a function of electrode material, temperature, and solution composition. Electrolysis of in , at 80°C using platinized nickel cathodes resulted in high current efficiency for the overall electrode reaction, a five‐electron reduction to dinitrogen. Ammonia is formed in constant current electrolyses at high current densities. The presence of oxygen in the cathode compartment was shown to increase the rate of nitrate reduction under these conditions. Nonideal cyclic voltammetric behavior was observed indicative of complex electrode processes.