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

CoPper oxide was supported on gamma-alumina and active carbon, CuO con tent was varied between 2 and 43.8 wt%. The active carbon-supported sp ecimens 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 soli ds were investigated using N2-adsorption at 196-degrees-C and oxidatio n 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 o f support material. Active carbon as a catalyst support was found to b e more convenient than Al2O3 for CuO loading <8 wt% while alumina is r ecommended for higher percentages of CuO. These results were discussed in terms of (i) the role of Al2O3 in increasing the degree of dispers ion of catalytically active constituents (copper oxide crystallites) w hile active carbon did not exert any change in the crystallinity of co pper oxide phase and (ii) the increase in precalcination temperature o f CuO/Al2O3 Solids enhanced the thermal diffusion of copper species fr om the uppermost surface layers towards the interior of the support le ading 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.