Synthesis of Pd/SiO2, Ag/SiO2, and Cu/SiO2 cogelled xerogel catalysts: study of metal dispersion and catalytic activity
(2004) Journal of Catalysis — Vol. 221, n° 2, p. 335-346 (2004)
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- Pd/SiO2, Ag/SiO2, and Cu/SiO2 xerogel catalysts have been synthesized by cogelation of tetraethoxysilane (TEOS) and chelates of Pd, Ag, and Cu with 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS). It appears that the metal complex acts as a nucleation agent in the formation of silica particles. The resulting catalysts are then composed of completely accessible metallic crystallites with a diameter of about 3 nm located inside silica particles exhibiting a monodisperse microporous distribution. The metal dispersion has been determined from CO and O-2 chemisorption, TEM, and X-ray diffraction. Although metallic particles are located inside silica particles, their complete accessibility, via the micropore network, has been shown. 1,2-Dichloroethane hydrodechlorination over Pd/SiO2 catalysts mainly produces ethane and the specific hydrodechlorination rate per gram of Pd decreases when metal loading increases. Hydrodechlorination over Pd/SiO2 catalysts is a structure-insensitive reaction with regard to the ensemble size concept. Benzene oxidation over Ag/SiO2 and Cu/SiO2 catalysts produces H2O and CO2 only and specific oxidation rate per gram of metal decreases when silver and copper loadings increase. Furthermore, it is concluded that benzene oxidation is a structure-insensitive reaction. (C) 2003 Elsevier Inc. All rights reserved.
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Lambert, S., Cellier, C., Grange, P., Pirard, JP., & Heinrichs, B. (2004). Synthesis of Pd/SiO2, Ag/SiO2, and Cu/SiO2 cogelled xerogel catalysts: study of metal dispersion and catalytic activity. Journal of Catalysis, 221(2), 335-346. https://doi.org/10.1016/j.jcat.2003.07.014 (Original work published 2004)