CHARACTERIZATION AND DEHYDROGENATION ACTIVITY OF CU AL2O(3) CATALYSTSPREPARED BY ELECTROLESS PLATING TECHNIQUE/

Seven new alumina supported copper catalysts prepared by the electrole ss copper plating method and the support itself were investigated to c haracterize by X-ray diffraction (XRD), scanning electron micrography (SEM) and electron probe microanalysis (EPMA). Dehydrogenations of iso propanol and cyclohexanol were individually conducted to test the acti vity of these catalysts. The copper surface area was measured by the s elective chemisorption of nitrous oxide and the acidity was measured b y the chemisorption of ammonia using the volumetric method. Besides th e BET surface area, pore size distribution was also measured. The resu lts showed that the BET surface area linearly decreased with the coppe r loading of the catalyst. Copper formed crystallites at a minimum loa ding (ca. 7 wt.% Cu) and the crystallite diameter (d(B)) was almost in dependent of loading. The copper surface area increased with copper lo ading up to ca. 15 wt.% Cu and then decreased with further deposits. T he acidity of catalyst also decreased with copper loading up to a cert ain copper content, further deposition of copper had no significant ef fect on it. The catalysts prepared by the electroless plating method s howed a relatively higher acidity than the catalysts prepared by the p recipitation method. It was found that the dehydrogenation activity st rongly depended upon the free exposed copper sites available for alcoh ol adsorption and reaction and the selectivity was a function of acidi ty of the catalysts as well as the reaction temperature.