Preparation of Cu/SiO2 catalyst by solution exchange of wet silica gel

Structural formation process of Ni/SiO2 and Cu/SiO2 catalysts prepared by s olution exchange of wet silica gel was investigated. Microstructures of Cu/ SiO2 and Ni/SiO2 were quite different from each other. In the case of Cu/Si O2, Cu particles with diameter of ca. 3-5 nm dispersed homogeneously at les s Cu content, and the particle size of Cu as well as pore size of silica ge l support increased with increasing Cu content. In the Ni/SiO2, the Ni part icles with diameter of ca. 6-10 nm gathered densely to form aggregates in s ilica matrix resulting in sea-island structure, whereas the size of Ni part icle slightly increased with increasing Ni content. The difference in the s tructure of the metal-silica composites is probably caused by the differenc e in interaction between silica gel network and metal ions during drying an d heating processes.