CHARACTERIZATION OF COPPER ALUMINA CATALYSTS PREPARED BY DEPOSITION-PRECIPITATION USING UREA HYDROLYSIS .1. NITROUS-OXIDE DECOMPOSITION AND REACTION OF ETHANOL

Copper-alumina catalysts with a wide range of copper loadings (4 to 34 wt.%) were prepared by depositing Cu2+ on suspended γ-alumina through precipitation from a homogeneous solution using urea hydrolysis at 90-95°C. The effect of copper content on the crystallographic phase and BET surface area of the catalysts calcined at 400°C for 24 h was investigated. Catalysts containing &le16 wt.-% copper did not show any copper containing phase indicating the presence of highly dispersed or amorphous copper species. These catalysts have shown high copper metal areas ranging from 308 to 108 m2/g-Cu as determined by the reaction of nitrous oxide with copper surfaces at 90°C. While catalysts with low copper content exhibited both dehydration and dehydrogenation activity, those with high copper content showed only dehydrogenation activity at reaction temperatures of 250-300°C. The selectivities for dehydrogenation products were correlated with copper areas of the catalysts.