Surface and Catalytic Properties of Al2O3, CuO/Al2O3 and ZnO/Al2O3 Systems

Abstract

Pure alumina, CuO/Al2O3 and ZnO/Al2O3 have been calcined in the temperature range 500–1000°C and the phase changes involved followed using DTA and XRD techniques. The surface properties of all the calcination products were determined from the adsorption of nitrogen at 77 K and the chemisorption of pyridine at 423 K. The catalytic conversion of isopropanol on all the thermal products was also investigated. The surface areas of CuO/Al2O3 and ZnO/Al2O3 decreased while the pore radii increased with increasing calcination temperature from 500°C to 1000°C. CuAl2O4 forms above 800°C while ZnAl2O4 crystallizes at 600°C The acidity of the surface decreased when the calcination temperature was increased above 500°C. The conversion of isopropanol proceeds via dehydration of the alumina catalysts. CuO/Al2O3 and ZnO/Al2O3 surfaces catalyze both the dehydration and dehydrogenation of this alcohol.