Palladium and platinum catalysts supported on carbon nanofiber coated monoliths for low-temperature combustion of BTX

Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, Campus Fuentenueva s/n, 18071 Granada, Spain; Catalysis Engineering, DelftChemTech, Faculty of Applied Sciences, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands
Applied Catalysis B Environmental (Impact Factor: 5.83). 07/2009; 89(3-4):411-419. DOI: 10.1016/j.apcatb.2008.12.021

ABSTRACT In this work carbon nanofiber (CNF)-coated monoliths with a very thin, homogeneous, consistent and good adhered CNF layer were obtained by means of catalytic decomposition of ethylene on Ni particles.The catalytic behaviour of Pt and Pd supported on the CNF-coated monoliths was studied in the low-temperature catalytic combustion of benzene, toluene and m-xylene (BTX) and compared with the performance of Pt and Pd supported on γ-Al2O3 coated monoliths.The catalysts supported on CNF-coated monoliths were the most active, independent of the metal catalyst or the type of the tested aromatic compound. TPD experiments showed that the γ-Al2O3 phase retained important amounts of the water molecules produced during the reaction. When water vapour was supplied to the reactant flow, the activity of Pd catalysts decreased much stronger than the Pt ones, and the activity of the Pt catalysts supported on the γ-Al2O3 was more affected than that of the catalysts supported on CNF.BTX combustion reactions seem to be catalyzed by Pt and Pd through different kinetic mechanisms, explaining why Pt catalysts always were more active than the Pd ones deposited on the same type of support. Pd catalyzed combustion of benzene is strongly inhibited by oxygen and by water.Catalysts supported on CNF-coated monoliths showed a selectivity to burn benzene better than toluene or m-xylene, attributed to a better aromatic-CNF surface interaction.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Hes6 is a member of the hairy-enhancer-of-split family of transcription factors that regulate proliferating cell fate in development and is known to be expressed in developing muscle. Here we investigate its function in myogenesis in vitro. We show that Hes6 is a direct transcriptional target of the myogenic transcription factors MyoD and Myf5, indicating that it is integral to the myogenic transcriptional program. The localization of Hes6 protein changes during differentiation, becoming predominantly nuclear. Knockdown of Hes6 mRNA levels by siRNA has no effect on cell cycle exit or induction of myosin heavy chain expression in differentiating C2C12 myoblasts, but F-actin filament formation is disrupted and both cell motility and myoblast fusion are reduced. The knockdown phenotype is rescued by expression of Hes6 cDNA resistant to siRNA. These results define a novel role for Hes6 in actin cytoskeletal dynamics in post mitotic myoblasts.
    Experimental Cell Research 07/2011; 317(11):1590-602. · 3.56 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Two series of Pt/C-catalysts were prepared using pure carbon aerogels as supports. The influence of porosity, surface chemistry and Pt dispersion on the activity of Pt/C combustion catalysts was analyzed. The synthesis of the supports was fitted to have a monomodal pore size distribution in the meso and macropore range respectively. Both supports were functionalized by oxidation treatment with H(2)O(2) or (NH(4))(2)S(2)O(8). These treatments did not modify the porosity significantly, but the surface chemistry changed from basic to acid as oxygen content increased. In this way, Pt-dispersion decreased as a result of the low thermal stability of surface carboxylic acid groups. Benzene was selected as target VOCs and the catalytic combustion performance depended mainly on the porous texture and Pt-dispersion, while the variations in the surface chemistry of carbon supports due to oxidation treatments seemed to have a weak influence on this kind of reaction.
    Journal of Hazardous Materials 11/2010; 183(1-3):814-822. · 3.93 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Direct vapor-phase upgrading of biomass pyrolysis products requires a catalytic reactor able to treat high reactant flow rates without generating a large pressure drop, because conventional pyrolysis reactors operate near atmospheric pressure. Monolithic catalysts exhibit important advantages that make them good candidates for this purpose. In this paper, low-surface-area Inconel monoliths were coated with in-situ-grown carbon nanofibers (CNFs), which were subsequently impregnated with catalytic species (Pt, Sn, and bimetallic Pt–Sn). These monoliths were tested for the deoxygenation of guaiacol and anisole (products of lignin pyrolysis), two of the most deactivating compounds present in pyrolysis oil. The main products obtained from these feeds on the monolithic catalysts were phenol and benzene. Coating with CNFs provides increased surface area and anchoring sites for the active species (Pt and Sn), thus increasing the yield of desired products. The bimetallic Pt–Sn catalysts showed higher activity and stability than monometallic Pt and Sn catalysts. These tests indicate that monoliths of Pt–Sn/CNF/Inconel are potentially effective catalysts for the vapor-phase upgrading of lignin fractions present in bio-oil.
    Energy & Fuels. 08/2011; 25(9).