نتایج جستجو برای: pt–based catalysts
تعداد نتایج: 32940 فیلتر نتایج به سال:
Increased oxygen reduction reaction (ORR) kinetics, improved CO tolerance, and more efficient water and heat management represent significant advantages that high-temperature polymer electrolyte fuel cells (HT-PEFCs) operating with a phosphoric acid-doped polybenzimidazole (PBI) membrane offer over traditional Nafion-based, low-temperature PEFCs. However, before such HT-PEFCs become viable, the...
Low temperature fuel cells are a promising clean energy source, which can directly convert the chemical energy stored in hydrogen and small organic molecules (e.g., methanol, ethanol, and formic acid) into electrical energy with high efficiency, and thus find extensive applications in, for instance, automobiles and portable electronic devices. However, the commercialization of fuel cells is ser...
The importance of solid catalysts for converting petroand bulk chemicals is reflected in the sheer magnitude of their market size: catalysts sales topped nine billion dollars in 2009. This large value mirrors also the increasing academic interest in heterogeneous catalysis research. As far as bulk chemicals (such as ethene, propene, and their derivatives) are concerned, there is a strong demand...
heteropoly acids (hpa) and their salts have advantages as catalysts which make them both economically and environmentally attractive, strong br?nsted acidity, exhibiting fast reversible multi-electron redox transformations under rather mild conditions, very high solubility in polar solvents, fairly high thermal stability in the solid states, and efficient oxidizing ability, so that they are imp...
supported catalysts synthesized via the interaction of mg(oet)2 with ticl4 in the presence or absence of an internal stereoregulating donor (di-n-butyl phthalate), with different solvents (chlorobenzene, n-undecane, n-heptane) at different titanation temperatures have been studied by a set of physicochemical methods. data on the chemical composition, x-ray structure and pore structure of these ...
in this research different types of al2o3 were used as supports to prepare catalysts for dehydrogenation of isobutane to isobutene. these supports were al2o3 from merck, axen and gamma al2o3 synthesized from al(oh)3. sn/pt/al2o3 catalysts were prepared by sequential impregnation, at first pt and then sn was deposited. characterization of catalysts was performed by x-ray powder diffraction (xrd)...
in this research na-y was synthesized by hydrothermal method and used as support for preparation of sn/pt/na-y catalysts using two different tin precursors, bu3sn(cl) and sncl2.2h2o, by sequential impregnation, in which the pt was deposited first and in the next step sn was deposited. the catalysts were characterized by h2 chemisorption, transmission electron microscopy (tem), scanning electro...
catalysts with the formula of laco(1+x)o(3+δ), where 0 ≤ x ≤ 1, were studied for oxidation of co and c2h6 in a synthetic exhaust gas, comprising 6.0 % co and 0.2 % c2h6 in ar. ethane was selected as a model for hydrocarbons in the exhaust gas. the performance of catalysts is correlated to their properties, particularly their redox in oxidizing and reducing atmospheres. xrd patterns show perovsk...
the stereospecific polymerization of conjugated dienes began in 1954 with the first catalysts obtained by combining ticl4 or ticl3 with aluminum-alkyls, i.e. the catalytic systems previously employed for ethylene and propylene polymerizations. subsequently, many other catalytic systems were obtained and examined by a combination of transition metal or lanthanide compounds with appropriate alkyl...
eethylene polymerization catalysts became available in an enormous variety. the challenge in this research is to find catalysts that are able to connect ethylene molecules in such a way that not only linear chains are produced but variations like branched materials that possess very interesting mechanical properties like linear low density polyethylene (lldpe). in this contribution, three diffe...
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