Effect of γ-irradiation on the sorptive properties of alumina-supported copper oxide catalysts

Abstract

CuO–Al 2O 3 samples containing different amounts of copper oxide were prepared by the mechanical mixing of individual oven-dried hydroxides of copper and aluminium and calcination at 823 K. The calcined samples were γ-irradiated with 10, 25, 50 or 90 Mrad. The textural properties of unirradiated and γ-irradiated CuO–Al 2O 3 catalysts were determined from N 2-adsorption at 77 K. The surface acidities of these unreduced catalysts were determined from the adsorption of pyridine at 423 K. Chemisorption of hydrogen and benzene on the reduced samples was performed at 400 K. The surface area S BET decreases and the mean pore radius r ̄ increases upon increasing CuO content of the unirradiated and γ-irradiated samples. The same situation was also observed with increasing irradiation dose. The adsorption of benzene and hydrogen increases with increasing copper content and irradiation dose, whereas the chemisorption of pyridine depicts an opposite trend. Moreover, the catalytic parameters of the samples investigated are influenced strongly by the metal loading and γ-irradiation dose.