نتایج جستجو برای: silica supported catalysts
تعداد نتایج: 257434 فیلتر نتایج به سال:
Reaction kinetics studies were conducted for the conversions of ethanol and acetic acid over silica-supported Pt and Pt/Sn catalysts at temperatures from 500 to 600 K. Addition of Sn to Pt catalysts inhibits the decomposition of ethanol to CO, CH4, and C2H6, such that PtSn-based catalysts are active for dehydrogenation of ethanol to acetaldehyde. Furthermore, PtSn-based catalysts are selective ...
Introduction The preparation and characterization of nanophase materials has received considerable attention in recent years, given their potential for improved performance as catalysts, high-strength materials, and semiconductor devices. For example, a recent breakthrough by Sun et al. (1) in the synthesis of highly-dispersed, silica-supported iron-platinum (FePt) bimetallic nanoclusters of co...
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...
Inclusion complexes of cyclodextrins with organometallic coordination compounds of Pd, Pt, Rh, Fe, Ni, and Ru have been used to produce porous metal-silica hybrid materials. The cyclodextrins are templates for the structure of the silica and lead to a uniform “wormtype” pore system. After the templating step the organometallic compounds can be employed as in situ precursors for the preparation ...
SBA-15 functionalization with mercaptopropyltrimethoxysilane has been used to prepare supported gold catalysts for the low temperature CO oxidation reaction. Supports and catalysts have been characterized by chemical analysis, CHS analysis, XRD, TGA, nitrogen adsorption-desorption at 77 K, TEM, CPMAS NMR, XPS and EPR. Catalytic runs have been carried out at atmospheric pressure and 313-623 K an...
A series of silica-supported Co-Mo samples prepared by the sol-gel method has been compared as catalysts for the synthesis of single-walled carbon nanotubes (SWNT). The concentration ratio of ammonium hydroxide to the silica precursor tetraethoxysilane (TEOS) has an important effect on the resulting morphology of the silica support and, consequently, on the nature of the Co-Mo catalytic species...
The information obtained from the characterization of vanadium oxide single crystal surfaces is related to the study of vanadia nanoparticles supported on silica and alumina thin films, model systems for the so-called ‘‘supported monolayer vanadia catalysts’’. It is found that these particles have properties similar to V2O3 surfaces, where the topmost V ions are involved in vanadyl groups and h...
Pd cathode catalysts for polymer electrolyte fuel cells have been covered with silica layers a few nanometres thick. The silica-coated Pd catalysts showed high activity and excellent durability for the oxygen reduction under the severe cathode conditions of PEFCs, while Pd catalysts without silica-coating were seriously deactivated under the same conditions. The coverage of Pd metal with silica...
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...
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