Characterization of supported copper catalysts for methanol dehydrogenation prepared from silica hydrogel

Abstract

Copper catalysts, prepared by mixing the active component in solution with silica hydrogel followed by drying and decomposition at low temperature were studied. Such catalysts were found to be satisfactory for the dehydrogenation of alcohols. Catalysts containing copper on SiO 2 and Cr 2O 3, prepared by this method were characterized by adsorption, X-ray diffraction (XRD), differential thermal analysis, thermogravimetric analysis and temperature-programmed reduction (TPR). Both fresh and used catalysts were studied. It was found by XRD that no interaction between the component and support took place during preparation and use of these catalysts. Silica taken in the hydrogel form controlled the growth of copper crystallites to a great extent. Inclusion of chromium oxide effectively controlled the texture of the catalyst and permitted prolonged use of the catalyst with high activity. The growth of copper crystallites in the presence of Cr 2O 3, was minimal. An analysis of TPR profiles threw further light on the quantity of copper available for reduction and the growth of copper particles and also confirmed the absence of phases formed by interaction of the components.