The effect of thermal treatment on the properties of sol-gel copper-silica catalysts

Copper-silica composites prepared by the sol-gel method were thermally treated at 110, 500, 900 and 1100 degreesC and studied by nitrogen adsorption, powder X-ray diffraction and temperature programmed reduction. Samples treated at 500 degreesC showed the highest surface area and copper exposed on the surface of the silica matrix resulting in a high catalytic activity for carbon monoxide oxidation. Treatment at 900 and 1100 degreesC produced the crystallization/densification of the samples with a strong decrease in sample area. As a result of these processes, the copper species were entrapped inside the vitreous silica matrix and the catalytic activity for carbon monoxide oxidation was strongly reduced. (C) 2001 Elsevier Science B.V. All rights reserved.