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

Copper-silica composites prepared by the sol-gel method were thermally trea ted at 110, 500, 900 and 1100 degreesC and studied by nitrogen adsorption, powder X-ray diffraction and temperature programmed reduction. Samples trea ted at 500 degreesC showed the highest surface area and copper exposed on t he 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 samp le area. As a result of these processes, the copper species were entrapped inside the vitreous silica matrix and the catalytic activity for carbon mon oxide oxidation was strongly reduced. (C) 2001 Elsevier Science B.V. All ri ghts reserved.