Ru/SiO2 catalysts prepared by the sol-gel method from RU3(CO)(12)

Ru/SiO2 catalysts were prepared by sol-gel methods from Ru-3(CO)(12), Or [R u3H(CO)(11)](-), Si(OMe)(4) (TMOS) and H2O, followed by thermal activation in helium up to 573 K and reduction with hydrogen. They were compared with Ru/SiO2 corresponding material prepared via sol-gel from RuCl3. The catalys ts were characterized by FT-IR spectra, surface area, metal dispersion and activity tests in the Fischer-Tropsch reaction at atmospheric pressure and CO/H-2 1:1, in the 473-573 K temperature range. The use of ruthenium cluste rs as precursors afforded higher metal dispersions than RuCl3, as well as h igher catalytic activities in the hydrogenation of CO (particularly in the absence of alkali or halogen ions retained in the gel structure). TEM inves tigations on the Ru/SiO2 material, prepared from Ru-3(CO)(12) by sol-gel, w ithout promoters, showed the presence of very fine metal particles homogene ously embedded in the silica matrix, with dimensions ranging from 1 to 4 nm . (C) 1999 Elsevier Science B.V. All rights reserved.