  Synthesis of very highly dispersed platinum catalysts supported on carbon xerogels by the strong electrostatic adsorption methodLambert, Stéphanie  ; Job, Nathalie ; et alin Journal of Catalysis (2009), 261 Highly dispersed Pt/carbon xerogel catalysts are obtained by applying the “Strong Electrostatic Adsorption” (SEA) of hexachloroplatinic acid to carbon xerogels (PZC = 9.4) and platinum tetraammine ... [more ▼] Highly dispersed Pt/carbon xerogel catalysts are obtained by applying the “Strong Electrostatic Adsorption” (SEA) of hexachloroplatinic acid to carbon xerogels (PZC = 9.4) and platinum tetraammine chloride to oxidized carbon xerogels (PZC = 2.4). After the reduction step, all these Pt/carbon xerogel catalysts display a very high level of metal dispersion: very small platinum particles (1.1-1.3 nm) are observed by TEM. Pt particle sizes obtained by CO chemisorption are in good agreement with TEM micrographs, which shows that the metal is accessible to reactants. These Pt/carbon xerogel catalysts are very active for the hydrogenation of benzene into cyclohexane. [less ▲] Detailed reference viewed: 75 (12 ULg)Highly dispersed platinum catalysts prepared by impregnation of texture-tailored carbon xerogelsJob, Nathalie ; ; Lambert, Stéphanie et alin Journal of Catalysis (2006), 240(2), 160-171 Pt/C catalysts were prepared by impregnation of carbon xerogels with H2PtCl6 aqueous solutions. Three supports with various pore textures were used: two micro-mesoporous (maximum pore size = 10 and 40 nm ... [more ▼] Pt/C catalysts were prepared by impregnation of carbon xerogels with H2PtCl6 aqueous solutions. Three supports with various pore textures were used: two micro-mesoporous (maximum pore size = 10 and 40 nm, respectively) and one micro-macroporous (maximum pore size = 70 nm). After impregnation, drying and reduction, the metal particles were at most 1-1.5 nm in diameter. The Pt dispersion was close to 100% in the case of the xerogel with large mesopores. For the two other supports, a small fraction of Pt was trapped in blocked micropores. The specific catalytic activity obtained for benzene hydrogenation was 4-10 times higher than that obtained with active charcoal-supported catalysts prepared by a similar method. The high dispersion of Pt was attributed to the presence in the xerogel of large mesopore or macropore volumes, which facilitates impregnation, and a low amount of oxygenated surface groups. (c) 2006 Elsevier Inc. All rights reserved. [less ▲] Detailed reference viewed: 51 (7 ULg) |
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