The literature on direct electrochemical reduction of NOx in a solid state cell has been reviewed. It is shown that that the reduction of nitric oxide either occurs on the electrode or on the electrolyte if F-centers are formed. It is also shown that some oxide based electrodes has a high apparent selectivity towards the reduction of nitric oxide in a net oxidizing atmosphere. The activity and apparent selectivity of oxide based electrodes is strongly dependent on the composition of the oxide. The selectivity of noble metal based electrodes is generally very low. However, coating of noble metal based electrodes can give current efficiencies of up to 20 % even in the presence of large amounts of oxygen.
- Fuel Cells and Hydrogen
- Flue gas purification