0000000000447751
AUTHOR
Norbert Kruse
Oxidation of CH4 over Pd supported on TiO2-doped SiO2: Effect of Ti(IV) loading and influence of SO2
Titania-modified silicas with different weight% of TiO2 were prepared by sol-gel method and used as supports for Pd (1 wt%) catalysts. The obtained materials were tested in the oxidation of methane under lean conditions in absence and in presence of SO2. Test reactions were consecutively performed in order to evaluate the thermal stability and poisoning reversibility. Increasing amounts of TiO2 improved the catalytic activity, with an optimum of the performance for 10 wt% TiO2 loading. Moreover, the titaniacontaining catalysts exhibited a superior tolerance towards SO2 by either adding it to the reactants or feeding it as a pure pretreatment atmosphere at 350 8C. Catalysts were characterize…
Mesoporous silicon carbide via nanocasting of Ludox® xerogel
Porous SiC with uniformly sized 12 nm and 22 nm spherical mesopores was synthesized from nanocomposites of polycarbosilane (PCS) preceramic polymer and xerogels of Ludox® SiO2 nanoparticles as templates. The influence of PCS type (Mw 800 and 2000 Da), PCS : SiO2 ratio, pyrolysis temperature 1200–1400 °C, and addition of Ni complex to the preceramic composite was studied with respect to the SiC porous morphology, crystalline structure and chemical properties. We found that the pore walls of Ni-free por-SiC are composed of relatively large (20 nm) crystallites embedded inside a poorly crystalline SiC/SiC1+x phase. Increasing the pyrolysis temperature resulted in an increase of the large cryst…
Superior Fischer-Tropsch performance of uniform cobalt nanoparticles deposited into mesoporous SiC
Electrochemically-derived well-crystalline mesoporous silicon carbide (pSiC) was used as a host for cobalt nanoparticles to demonstrate superior catalytic performance during the CO hydrogenation according to Fischer-Tropsch. Colloidal Co nanoparticles (9 ± 0.4 nm) were prepared independently using colloidal recipes before incorporating them into pSiC and, for comparison purposes, into commercially available silica (Davisil) as well as foam-like MCF-17 supports. The Co/pSiC catalyst demonstrated the highest (per unit mass) catalytic activity of 117 µmol.g(CO)-1.g-1(Co).s-1 at 220 °C which was larger by about one order of magnitude as compared to both silica supported cobalt catalysts. Furthe…