Spectroscopic Study of CuO/CoO Catalysts Supported by Si-Al-Y Zeolite Matrices Prepared by Two Sol-Gel Methods

摘要

Two different sol-gel methods for silica-aluminates have been used for catalyst preparation, one based on inorganic precursors, aluminum nitrate and sodium silicate, and a second based on alkoxides, aluminum trisec-butoxide (ATB) and tetra-ethoxy-silane (TEOS). A third element, Y-zeolite was incorporated in both of the gel matrices during the process, in order to alter the acid properties of the catalyst. Although the final compound has approximately the same chamical composition, the crystalline structures of the two catalysts are substantially different. The support made from inorganic precursor yielded a more hydroxylated surface, whereas the support based on organic precursors readily incorporated the metals into the network, The support from organic precursors showed almost total dehydroxylation. The Co-Cu complexes formed at the catalyst surface differ greatly, depending on the preparation method.