CeO2/Pt Catalyst Nanoparticle Containing Carbide-Derived Carbon Composites by a New In situ Functionalization Strategy
Résumé
new class of CeO2/Pt nanostructures containing highly porous carbide-derived carbon composites was obtained for the first time using a polymer precursor strategy and subsequent ceramization. The catalytic transition metal compounds were incorporated into polymeric polycarbosilane structures using an inverse microemulsion method in precisely tunable nanoscale particle sizes. Porous ceramic and carbon composites were obtained by pyrolysis and subsequent chlorination processes. The adsorption properties of nonoxidic ceramic intermediates can be adjusted by the pyrolysis temperatures from mainly microporous to mcso- and macroporous materials, respectively. These pore structures remain during the chlorination process confirmed by comparative nitrogen physisorption and small-angle X-ray scattering investigations. The specific surface areas significantly increase up to 1774 m(2)/g after selective silicon removal. In comparison to unsupported CeO2/Pt nanoparticle structures, the particle sizes and dispersion of the active metal compounds of composite structures remain during pyrolysis and chlorination process studied by electron microscopy methods. Ceramic and carbonaceous composites show catalytic activity and stability in selective methane oxidation. In contrast to the SiC composites, the CDC materials promote the formation of carbon monoxide and hydrogen in reforming reactions at higher temperatures, a conversion pathway important for the generation of synthetic fuels.