Abstract: The properties of the RuO₂|M|YSZ|Pd(M=Ag, Pd, Pt, Au) cells for NO decomposition in the presence of excess O₂were studied.The applied DC voltage was ranged from₁to 4V, and the reaction was proceeded at the temperatures between 500 and 750℃. It is proposed that on the RuO₂|Pd|YSZ|Pd cell at 600℃, the transportation of O^2-on the Pd|YSZcathode interface is the rate-determining step in the overall O^2-ion transportation process in the cell.The RuO₂|Pd|YSZ|Pd cell tends to achieve a higher selectivity of the NO electrocatalysis decomposition compared to relative O₂ionization at a lower reaction temperature.At 600 ℃, the resistance of O^2-transportation on the M|YSZcathode interface increases in the order of Ag<Au<Pd<Pt.By using Ag instead of Pd as the cathode, the current density through the RuO₂|M|YSZ|Pd cell was effectively enhanced, which made the RuO₂|Ag|YSZ|Pd cell being used at the lower temperature possible and thus the property for NO decomposition was improved.At 500℃, the RuO₂|Ag|YSZ|Pd cell shows better properties for NO decomposition, and in the cell the NO conversion reaches 15.3% and the NO decomposition selectivity factor α reaches 13.4.

Key words: NO electro-decomposition, O₂-transportation, Rate-determining step, YSZ