نتایج جستجو برای: catalyst surface reaction

تعداد نتایج: 1046577  

In this study, we report removal of Diclofenac (DCF) through heterogeneous Fenton process using Fe-ZSM-5 catalyst. The parent catalyst was prepared by hydrothermal technique. Fe species were introduced by wet impregnation. Characterization of the catalysts was carried out using XRD, FT-IR, FE-SEM, N2 adsorption-desorption, NH3-TPD, and acidimetric-alkalimetric titration. The bimetallic catalyst...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2011
Gabor A Somorjai Yimin Li

The applications of molecular surface chemistry in heterogeneous catalyst technology, semiconductor-based technology, medical technology, anticorrosion and lubricant technology, and nanotechnology are highlighted in this perspective. The evolution of surface chemistry at the molecular level is reviewed, and the key roles of surface instrumentation developments for in situ studies of the gas-sol...

2004
X. Ouyang L. Bednarova P. Ho R. S. Besser

Silicon microreactors with thin-film wall catalyst were adopted for kinetic studies of CO preferential oxidation (PrOx). The activity of this catalyst was compared to other catalyst systems based on similar formulation. Internal and external mass transport and heat transport limitations of the microreactor were examined and comparisons were made to typical packed-bed lab reactors (m-PBR's). We ...

Journal: :polyolefins journal 2015
nickolay ostrovskii ladislav fekete

the olefins polymerization process in a slurry reactor is discussed. the reaction rate dynamics was analyzed and the contributions of feed flow, gas-liquid mass transfer, polymerization reaction, and catalyst deactivation were estimated. the propylene solubility in a solvent mixture “heptane” was calculated using soave-redlich-kwong equation of state. these data were then approximated by henry-...

To discuss the potential role of the support for iridium catalyst, we have proceeded to prepare a series of supported catalysts with the same active phase content, but different silica content, to elucidate the changes in surface structure and the reaction process of hydrous hydrazine decomposition on catalyst. The obtained iridium catalysts contained 20 wt% of nanoparticles dispersed on spheri...

2008
Weiling Deng Anatoly I. Frenkel Rui Si Maria Flytzani-Stephanopoulos

Combined in situ X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) studies have been conducted to follow gold structural changes of low-content (<1%Au) gold-ceria catalysts in water-gas shift (WGS) reaction tests at 100 and 200 °C; and after heating the used catalysts in oxygen gas at 150 °C. Gold in the fresh (400 °C-calcined) material was atomic...

2015

1. Electrocatalysis: This is one of the direct examples of the homogeneous reaction diffusion regime. This involves multiple steps, i.e. diffusion, adsorption and a possible charge transfer at the surface (x = 0). As shown in the schematic of Fig(1), species will adsorb on the catalyst surface, then diffuse along the surface to the right/left surfaces where a charge transfer reaction can occur....

2016
O. A. OLAFADEHAN A. A. AYOOLA V. O. ADENIYI O. A. Olafadehan

Mechanistic kinetic models were postulated for the catalytic steam reforming of concentrated crude ethanol on a Ni-based commercial catalyst at atmosphere pressure in the temperature range of 673-863 K, and at different catalyst weight to the crude ethanol molar flow rate ratio (in the range 0.9645-9.6451 kg catalyst h/kg mole crude ethanol) in a stainless steel packed bed tubular microreactor....

Journal: :Journal of the American Chemical Society 2015
Nigel Becknell Yijin Kang Chen Chen Joaquin Resasco Nikolay Kornienko Jinghua Guo Nenad M Markovic Gabor A Somorjai Vojislav R Stamenkovic Peidong Yang

Understanding the atomic structure of a catalyst is crucial to exposing the source of its performance characteristics. It is highly unlikely that a catalyst remains the same under reaction conditions when compared to as-synthesized. Hence, the ideal experiment to study the catalyst structure should be performed in situ. Here, we use X-ray absorption spectroscopy (XAS) as an in situ technique to...

Journal: :The Review of scientific instruments 2013
Franklin Feng Tao Luan Nguyen Shiran Zhang

Here, we present the design of a new reactor-like high-temperature near ambient pressure scanning tunneling microscope (HT-NAP-STM) for catalysis studies. This HT-NAP-STM was designed for exploration of structures of catalyst surfaces at atomic scale during catalysis or under reaction conditions. In this HT-NAP-STM, the minimized reactor with a volume of reactant gases of ∼10 ml is thermally is...

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