Novel route of synthesis of Sn-coated SBA-15

A series of Sn-modified SBA-15, was studied. On top of Sn-only modified materials, several materials were modified with Sn and then Ti or with Sn and then Al. The new materials were obtained by adsorption of vapors of metal chlorides on SBA-15 (at 30–110 °C), and hydrolysis of adsorbed chlorides by water vapor at 25 °C, and then evaporation of left-overs of volatile compounds at 140 °C. The Sn-modified SBA-15 had lower specific surface area, and a higher thermal stability than the original silica. Even in materials containing substantial amount of Sn, the presence of crystalline phases representing Sn compounds was not detected by XRD. In contrast, rutile and anatase were observed in Sn- and Ti-modified SBA-15 while crystalline phases representing Ti compounds were not detected when Ti was deposited directly on SBA-15 (not modified with Sn). The profiles of Sn concentration across the particles of Sn-modified SBA-15 indicate that Sn is located in the pores rather than on the external surface.