EFFECT OF PREPARATION METHODS OF CeO2-MnOx MIXED OXIDES ON PREFERENTIAL OXIDATION OF CO IN H2-RICH GASES OVER CuO-BASED CATALYSTS

Abstract

The CeO 2 -MnO x mixed oxides were prepared by deposition-precipitation (DP) and surfactant-templated (CB) methods, and then used as the support of CuO/ CeO 2 -MnO x catalysts. The samples were characterized by means of XRD, BET, H 2 -TPR, CO-TPD and XPS. Results show that preparation methods of CeO 2 -MnO x support have a direct effect on the physicochemical properties and catalytic activities of CuO/CeO 2 -MnO x catalysts for the CO preferential oxidation in H 2 -rich gases(CO PROX). CuO/CeO 2 -MnO x (CB) catalyst exhibits higher CO conversion and stability in H 2 -rich gases than CuO/CeO 2 -MnO x (DP), with 100% conversion of CO at 140 °C after a temperature cycle, which indicates that CeO 2 -MnO x (CB) as support of CuO based catalyst is more useful for CO PROX reaction than CeO 2 -MnO x (DP). Compared with CuO/CeO 2 -MnO x (DP), there are richer oxygen vacancies and more Mn4+ species on the surface of CuO/CeO 2 -MnO x (CB), and stronger interaction between CeO 2 and MnO x in it. More amounts of active copper species and complicated transfer of electrons density on CuO/CeO 2 -MnO x (CB) also favour the activity of the catalyst.