The promotional effect of preparation methods on catalytic reduction of NO by CO over CoCeOx catalysts

In this study, a series of CoCeOx catalysts were prepared by template, solid-state grinding with cobalt sulfate or cobalt acetate as precursor and oil bath method for catalytic reduction of NOx by CO (CO-NO). These catalysts were characterized by XRD, BET, Raman, XPS, H2-TPR and in-situ DRIFTS. The results indicated that CoCeOx-TA and CoCeOx-SS catalysts exhibited much higher activity, which were attributed to excellent reducibility property, abundant chemical adsorbed oxygen and NO absorption sites. In the presence of O2, the activity decreased obviously over CoCeOx-TA, CoCeOx-SS and CoCeOx-SA catalysts. However, the activity increased at high temperatures over CoCeOx-OA catalyst. According to the result of in-situ DRIFTS, nitrate species decreased over CoCeOx-TA, CoCeOx-SS and CoCeOx-SA catalysts in the presence of O2, which might inhibit the reduction efficiency of NO. Moreover, NO adsorption was not affected by O2 over CoCeOx-OA catalyst, which could contribute to its high activity in CO-SCR reaction.