Effect of CeO 2-doping on surface and catalytic properties of CuO–ZnO system

Abstract

The effect of doping CuO–ZnO system with CeO 2 on its surface and catalytic properties was investigated using nitrogen adsorption at −196 °C, EDX technique and catalysis of CO oxidation by O 2 at 100–200 °C. Pure mixed solids were prepared by thermal decomposition of copper/zinc mixed hydroxides at 400 °C. The doped solids were obtained by impregnating a known mass of mixed hydroxides with calculated amount of cerium ammonium nitrate followed by drying then calcination at 400 °C. The dopant concentration was 1.5, 3.0 and 4.5 mol% CeO 2. The results revealed that CeO 2-doping modified the surface atomic Cu/Zn ratio of the system investigated and changed the crystallite size of both CuO and ZnO phases. The increase of the amount of dopant added changed the major phase present. This treatment decreased the specific surface area of doped solids. The doping process modified also the catalytic activity in a manner dependent on both mode of preparation and dopant concentration. However, CeO 2-doping did not modify the mechanism of the catalytic reaction but changed the concentration of catalytically active sites involved in the catalyzed reactions.