Engineering of lattice defects in supported Cu-Mn-Ce composite oxide catalysts through ultra-low Pd doping and plasma treatment for catalytic oxidation of hexane

Abstract

Despite the low cost of supported non-precious metal catalysts, their catalytic activity is significantly lower than that of precious metal catalysts in the catalytic oxidation reaction of volatile organic compounds (VOCs). In order to enhance the catalytic activity of supported non-precious metal catalysts, we introduced an ultra-low loading of palladium into the existing catalytic system and employed a plasma preparation process instead of the conventional impregnation method. The approach significantly improves the catalytic activity of the active sites on the catalyst. The results indicate that, compared to the supported Pd and CuMnCeO_x catalysts prepared by conventional impregnation method, the Pd/CuMnCeO_x/SiO₂-P catalysts prepared via plasma exhibit a higher proportion of lattice defects (oxygen vacancies). Furthermore, the doping of the ultra-low Pd could facilitate the formation of additional lattice defects in the composite oxide. As a result, it can improve the content of surface active oxygen and enhance the adsorptive strength of hexane on the surface of the catalyst. The Pd/CuMnCeO_x/SiO₂-P catalysts exhibit high catalytic activity and stability in the catalytic oxidation of n-hexane. This work promotes the potential application in the preparation of catalyst with ultra-low precious metal loading.