Effects of the Ba Impregnation on Pt Electrode on NO Electrochemical Reduction Mechanism

The study investigated the electrochemical reduction performances of NO and O2 on Pt symmetric electrode with Ba adsorption layer. The temperature varied from 350°C to 550°C. The experimental Ba (NO3)2 solution was impregnated in the Pt electrode. For the NO performance, the polarization curves and CV tests showed that the Pt-BaO electrode showed higher electrochemical performance than Pt electrode. EIS results revealed that the Pt-BaO electrode exhibited higher activity than the Pt electrode. It was due to the decreased polarization resistance in the low-frequency region that dominated the electrochemical impedance spectra. The increase of temperature strengthened the effect of adsorption layer on NO electrochemical performance. The EIS results were fitted well with the equivalent circuit model indicating that the improved mechanism with the Ba adsorption layer may be related with the NO oxidation to NO2 on the Pt surface, the formation of Ba (NO3)2 in the adsorption layer and the reduction of the reaction path from the direct Ba (NO3)2 decomposition.