SURFACE AND CATALYTIC PROPERTIES OF COPPER-OXIDE SUPPORTED ON AL2O3 AND ACTIVE-CARBON

CoPper oxide was supported on gamma-alumina and active carbon, CuO content was varied between 2 and 43.8 wt%. The active carbon-supported specimens were heated at 300-degrees-C under a reduced pressure of 10(-6) Torr while CuO/Al2O3 solids were heated in air at 300-1100-degrees-C. The surface characteristics and catalytic properties of various solids were investigated using N2-adsorption at 196-degrees-C and oxidation of CO by O2 at 135-240-degrees-C respectively. The results obtained revealed that the surface and catalytic properties of different solids were dependent upon CuO content, calcination temperature and nature of support material. Active carbon as a catalyst support was found to be more convenient than Al2O3 for CuO loading <8 wt% while alumina is recommended for higher percentages of CuO. These results were discussed in terms of (i) the role of Al2O3 in increasing the degree of dispersion of catalytically active constituents (copper oxide crystallites) while active carbon did not exert any change in the crystallinity of copper oxide phase and (ii) the increase in precalcination temperature of CuO/Al2O3 Solids enhanced the thermal diffusion of copper species from the uppermost surface layers towards the interior of the support leading to a decrease in surface concentration of copper species and to the formation of copper aluminate having a catalytic activity smaller than that of CuO solid.