Polydimethylsiloxane (PDMS) has been synthesized by ring-opening polymerization of octamethylcyclotetrasiloxane (D4) in microemulsion with acidic catalyst. The structure and properties of microemulsion were characterized by Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR), Photo Correlation Spectroscopy (PCS). The effect of the variation in pH value, amoun...

Platinum and Pt alloy nanoparticles supported on carbon are the state of the art electrocatalysts in proton exchange membrane fuel cells. To develop a better understanding on how material design can influence the degradation processes on the nanoscale, three specific Pt/C catalysts with different structural characteristics were investigated in depth: a conventional Pt/Vulcan catalyst with a par...

In a gas phase %uidized bed ole)n polymerization reactor, it is generally assumed that polymer particles are well mixed and near isothermal reaction conditions prevail. When a highly active Ziegler–Natta catalyst or other type of high activity supported catalyst is used in a gas phase %uidized bed reactor, a certain heterogeneity in the polymer properties is often observed in di4erent size part...

Gas phase polymerization of propylene was carried out in a semi-batch minireactor using a commercially supported Ziegler–Natta (ZN) catalyst. The influence of variables including monomer partial pressure, external electron donor, reaction temperature and time on the particle morphology and size distribution was investigated. Generally, more uniform fragmentation and particle densities were obta...

This study focuses on the effect of the synthetic conditions on the stability, particle size, redox chemistry of cobalt into the framework of CoAlPO-34. It seems that the most sufficient pH for the substitution of Co into the framework of CoAlPO-34 was pH around 7.5 when the assynthesized bifunctional catalyst has the best redox property. The pH of the initial gel has strong effect on the parti...

Oxidation of cyclooctene was studied in presence aqueous hydrogen peroxide (30%, v/v) over nano iron oxide. The catalyst prepared by microemulsion method and characterized using various techniques including XRD, TEM and BET techniques for evaluating phase, structure and morphology and surface area. In this study, we investigated the effects of varying the catalyst content, reaction temperature,...

A novel high surface area heterogeneous catalyst based on solution phase colloidal nanoparticle chemistry has been developed. Monodisperse platinum nanoparticles of 1.7-7.1 nm have been synthesized by alcohol reduction methods and incorporated into mesoporous SBA-15 silica during hydrothermal synthesis. Characterization of the Pt/SBA-15 catalysts suggests that Pt particles are located within th...

A parametrized mesoscale model for the early stage growth of isolated single or multiwall carbon nanotubes (CNTs) has been developed in order to investigate the effects of metal catalyst particle size and composition on CNT growth mechanism during synthesis via a substrate-supported, catalytic chemical vapor deposition process. The model is based on a coarse-grained graphene sheet, represented ...

Palladium nanoparticles were grown on sub-millimeter activated Al2O3 particle support by spraying H2PdCl4 solution evenly onto the support, followed with a thermal reduction under H2 atmosphere. Compared with its counterpart created by the conventional impregnation method, the Pd/Al2O3 catalyst created by the spray process could enrich the existence of active Pd nanoparticles on the surface of ...

Aiming at a detailed understanding of the role of metal−support interactions in the selective methanation of CO in CO2-rich reformate gases, we have investigated the catalytic performance of a set of Ru/TiO2 catalysts with comparable Ru loading, Ru particle size, and TiO2 phase composition but very different surface areas (ranging from 20 to 235 m g−1) in this reaction. The activity for CO meth...