نتایج جستجو برای: silica supported

تعداد نتایج: 229959  

2009
A. Ueno N. Kakuta K. H. Park M. F. Finlayson A. J. Bard A. Campion M. A. Fox S. E. Webber J. M. White

The Journal of Physical Chemistry is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Silica-supported ZnS.cntdot.CdS mixed semiconductor catalysts for photogeneration of hydrogen A. Ueno, N. Kakuta, K. H. Park, M. F. Finlayson, A. J. Bard, A. Campion, M. A. Fox, S. E. Webber, and J. M. White J. Phys. Chem., 1985, 89 (18), 3828-3833 • DOI: 10.1021/j10...

2009
R. Berthoud P. Délichère D. Gajan W. Lukens K. Pelzer J.-M. Basset J.-P. Candy C. Copéret

Treatment under H2 at 300 °C of Ru(COD)(COT) dispersed on silica yields 2 nm ruthenium nanoparticles, [Rup/SiO2], according to EXAFS, HRTEM and XPS. H2 adsorption measurements on [Rup/SiO2] in the absence of O2 show that Ru particles adsorb up to ca. 2 H per surface ruthenium atoms (2H/Rus) on various samples; this technique can therefore be used to measure the dispersion of Ru particles. In co...

2005
Duncan J. Macquarrie Stefan Toma

Research into supported palladium complexes is described. The complexes are immobilised on porous silica supports using both grafting and templated sol-gel techniques. The resultant complexes are efficient catalysts for various C-C bond forming reactions, including Heck, Suzuki and allylic substitution. The catalysts are stable and can be easily recovered and reused, making them suitable for cl...

2001
Xueping Xu Peijun Chen Wayne Goodman

The coadsorption of nitric oxide and carbon monoxide on Pd( loo), Pd( 11 l ) , and a model silica-supported palladium catalyst has been investigated with infrared reflection-absorption spectroscopy (IRAS) in the temperature range 100-500 K. The palladium surfaces were in equilibrium with a 1 X l P Torr equimolar mixture of CO and NO during the FT-IRAS studies. The structure and coverage of the ...

Journal: :Chemical communications 2004
Catherine J Miller Dermot O'Hare

A new bis(indenyl)zirconocene bearing a pendant Si-Cl anchor has been grafted onto MCM-41, SBA-15, MCM-48 and a disordered mesoporous silica for the polymerisation of ethylene and propylene, producing polymers with very high molecular weights, low polydispersities and, in the case of polypropylene, higher levels of isotacticity than obtainable with analogous homogeneous systems.

2003

In previous chapters, the synthesis of a highly hydrogen selective membrane formed by the deposition of a silica layer on top of a Vycor glass substrate was discussed. In this chapter, the preparation of a composite membrane using a porous alumina support is described. This membrane showed a high hydrogen permeance of the order of 10 mol m s Pa at 873 K with selectivity of hydrogen over CH4, CO...

2012
Zhen Yan D. Wayne Goodman

Inspired by previous studies on model systems, a series of silica-supported Au–Ni catalysts were prepared and tested for the conversion of propane in the presence of hydrogen. The Au–Ni/SiO2 catalysts were prepared by successive impregnation, i.e. Ni was deposited first followed by Au. TEM/EDX results confirmed the presence of bimetallic Au–Ni nanoparticles. The dehydrogenation of propane to pr...

Journal: :Nano letters 2006
Brian White Ming Yin Andrew Hall Duy Le Sergey Stolbov Talat Rahman Nicholas Turro Stephen O'Brien

We find that nearly monodisperse copper oxide nanoparticles prepared via the thermal decomposition of a Cu(I) precursor exhibit exceptional activity toward CO oxidation in CO/O2/N2 mixtures. Greater than 99.5% conversion of CO to CO2 could be achieved at temperatures less than 250 degrees C for over 12 h. In addition, the phase diagram and pathway for CO oxidation on Cu2O (100) is computed by a...

2014
Fen Fu Liang Guang Tian Sheng Xu Xian Gang Xu Xiao Bo Hu

Stable amorphous calcium carbonate supported by mesoporous silica gel was successfully synthesized. The silica gel support is prepared through the hydrolytic polycondensation of ethyl silicate under suitable conditions. Laser scanning confocal microscopy (LSCM) observations reveal that the morphology of the products is branched with cruciform-like and flower-like structure. Raman spectroscopic ...

Journal: :Chemcatchem 2022

The Cover Feature shows an artistic interpretation of a supported polymerization catalyst particle that is fragmenting during ethylene polymerization. In their Research Article, F. Meirer, B. M. Weckhuysen and co-workers used high resolution X-ray electron microscopy to elucidate the origins sectioning fragmentation mechanism in two different silica-supported olefin catalysts at single level. o...

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