Besides its current applications, ammonia (i.e. carbon-free fuel) could play important roles in preparing for oil depletion and coping with climate change since it releases only nitrogen and water when burned. Ammonia contains 17.6wt% of hydrogen and has significant advantages over hydrogen in storing and transporting energy.
The current industrial ammonia production is based on the Haber-Bosch process, which has the drawbacks of high greenhouse gas emission, reaching up to 2.16 kg CO2/kg NH3 and large energy consumption over 30 GJ/ton NH3 resulting from the production of the reactants and the high pressure-high temperature synthesis of ammonia. In order to avoid the aforementioned drawbacks, an alternative process is the electrochemical synthesis of ammonia from water and nitrogen at atmospheric pressure.
In the present contribution, the electrochemical synthesis of ammonia from nitrogen and steam has been experimentally investigated using solid state oxygen ion (O2-) and proton (H+) conductors. The effects of temperature, applied current and electrode composition on the ammonia formation rate will be discussed.