نتایج جستجو برای: various catalysts

تعداد نتایج: 797949  

Ni catalysts supported on Nano porous catalysts were prepared by the impregnation method and tested for vapor phase hydrogenation of benzene. The textural and physico-chemical properties of Ni catalysts were characterized by the X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscope and N2 adsorption-desorption analysis. The catalytic evaluation reve...

2000
M. A. FARDAD

In the fabrication of silica films by sol-gel synthesis, the role of various catalysts is systematically examined. The precursor solutions were made by mixing tetraethylorthosilicate (TEOS), ethanol and water in the molar ratio of 1 : 2 : 2. The spin coated films were thermally treated at various temperatures, and characterised using ellipsometry, molecular probe ellipsometry (MPE), infrared sp...

Journal: :Journal of the American Chemical Society 2013
Jin-Xun Liu Hai-Yan Su Da-Peng Sun Bing-Yan Zhang Wei-Xue Li

Identifying the structure sensitivity of catalysts in reactions, such as Fischer-Tropsch synthesis from CO and H2 over cobalt catalysts, is an important yet challenging issue in heterogeneous catalysis. Based on a first-principles kinetic study, we find for the first time that CO activation on hexagonal close-packed (HCP) Co not only has much higher intrinsic activity than that of face centered...

Journal: :Chemical Society reviews 2015
Alfons Baiker

In view of the importance of optically pure chiral products there is ample reason to develop methods that facilitate their efficient production. Compared to the mostly applied homogeneous catalysts based on transition metals coordinated to suitable chiral ligands, heterogeneous chiral catalysts could offer several features that are beneficial for practical application such as stability, ease of...

Journal: :Chemistry 2006
Kuiling Ding Zheng Wang Xingwang Wang Yuxue Liang Xisheng Wang

The development of heterogeneous chiral catalysts for enantioselective reactions is highly desirable in order to overcome some drawbacks of homogeneous catalysts. Different from the conventional approaches by using various types of supports or biphasic systems for the recovery and reuse of homogeneous catalysts, a conceptually new strategy for heterogenization of homogeneous chiral catalysts, t...

2005
T. Guo

Single-wall carbon nanotubes (SWNTs) are usually produced with the help of metal catalysts that first break down various carbon species such as graphite, carbon clusters, amorphous carbon, or hydrocarbons and then release them in the form of SWNTs. These catalysts therefore must perform several functions in order to produce high quality, high yield, long SWNTs, and the finesse of these catalyst...

2010
Qiang Lu Zhi-Fei Zhang Chang-Qing Dong

Fast pyrolysis of poplar wood followed with catalytic cracking of the pyrolysis vapors was performed using analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The catalysts applied in this study were nano MgO, CaO, TiO2, Fe2O3, NiO and ZnO. These catalysts displayed different catalytic capabilities towards the pyrolytic products. The catalysis by CaO significantly reduced the ...

2016
Yuxian Wang Yongbing Xie Chunmao Chen Xiaoguang Duan Hongqi Sun Shaobin Wang

Magnetic core/shell nanospheres (MCS) were synthesized by a novel and facile one-step hydrothermal method. Supported manganese oxide nanoparticles (Fe3O4/C/Mn) were obtained from various methods (including redox, hydrothermal and impregnation) using MCS as the support material and potassium permanganate as the precursor of manganese oxide. The Mn/MCS catalysts were characterized by a variety of...

Journal: Polyolefins Journal 2016

Ethylene polymerization was carried out using Phillips chromium catalyst based on silica supports such as silica aerogel, SiO2 (Grace 643), and titanium modified SiO2 (G 643), and the results were compared with other catalysts based on SiO2 (Aldrich), SBA-15(Hex), SBA-15(Sp) and MCM-41. A combination of TGA, DSC, XRD, nitrogen adsorption, SEM, ICP, FTIR and other analyses were used to character...

Journal: :inorganic chemistry research 0
mehdi araghi department of chemistry, saveh branch, islamic azad university, saveh, iran shaghayegh aghamohammad department of chemistry, saveh branch, islamic azad university, saveh, iran

in the present work, highly efficient oxidation of sulfides catalyzed by moo2(acac)2 supported on multi-wall carbon nanotubes, mwcnts, modified with 1,2-diaminobenzene (dab) and 2-aminophenol (ap), at room temperature are reported. the effects of various parameters such as reaction time, solvent, catalyst amount, oxidant, etc, were studied. these heterogenized catalysts showed high activity in ...

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