Electrochemical removal of both NO and CH4 under lean-burn conditions

An electrochemical cell, Pd|YSZ|Pd, was constructed in order to remove both NO and CH₄ in the presence of excess oxygen. When direct current was supplied to the cell with a flow of a mixture of NO, CH₄, O₂, H₂O and CO₂ at 700° C, NO was reduced to nitrogen at the cathode, and CH₄ was oxidized to CO_x at both the anode and cathode. At the cathode, the reduction of NO and the oxidation of CH₄ proceeded with the removal of chemisorbed oxygen species from the Pd surface, and at the anode, the oxidation of CH₄ was enhanced by forming an active oxygen atom.