Electrochemical Synthesis of Nitrite and Nitrate via Cathodic Oxygen Activation in Liquefied Ammonia

The electrochemical oxidation of ammonia (NH3) enables decentralized small-scale synthesis of nitrate (NO3–) and nitrite (NO2–) under ambient conditions by directly utilizing renewable energy. Yet, their electrosynthesis has been restricted to aqueous media and low ammonia concentrations. For the first time, we demonstrate here a strategy enabling the direct electrooxidation of liquefied NH3 to NO3– and NO2– by using molecular oxygen, achieving combined Faraday efficiencies above 40%.