Keggin Structure and Surface Acidity of 12-Phosphotungstic Acid Grafted Zr-MCM-48 Mesoporous Molecular Sieves
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Keggin Structure and Surface Acidity of 12-Phosphotungstic Acid Grafted Zr-MCM-48 Mesoporous Molecular Sieves
A zirconium modified MCM-48 mesoporous material was synthesized by surfactant-templated method. Surface grafting Zr-MCM-48 with tungstophosphoric acid led to a great enhancement of both the number of the Brønsted acid sites and acidity strength in comparison with the bare support. At 100 ̊C, the 30 wt% H3PW12O40/Zr-MCM-48 contained 174 mol/g Brønsted acid sites which were 21.7 times greater tha...
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Chemical vapor deposition was employed to synthesize carbon nanotubes with Ni-loaded MCM-41 and MCM-48 as catalysts and acetylene as precursor at 750°C. Mesoporous Ni MCM-41 and Ni MCM-48 molecular sieves were synthesized by a hydrothermal method and were characterized by XRD and N2 adsorption isotherm. The catalytically synthesized carbon materials were characterized with Raman spectroscopy, N...
متن کاملtemplated growth of carbon nanotubes on nickel loaded mesoporous mcm-41 and mcm-48 molecular sieves
chemical vapor deposition was employed to synthesize carbon nanotubes with ni-loaded mcm-41 and mcm-48 as catalysts and acetylene as precursor at 750°c. mesoporous ni mcm-41 and ni mcm-48 molecular sieves were synthesized by a hydrothermal method and were characterized by xrd and n2 adsorption isotherm. the catalytically synthesized carbon materials were characterized with raman spectroscopy, n...
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A commercially available Hoveyda-Grubbs type catalyst (RC303 Zhannan Pharma) was immobilized on mesoporous molecular sieves MCM-41 and on SBA-15 by direct interaction with the sieve wall surface. The immobilized catalysts exhibited high activity and nearly 100% selectivity in several types of alkene metathesis reactions. Ru leaching was found to depend on the substrate and solvent used (the low...
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The recently discovered mesoporous aluminosilicate MCM-41 consists of hexagonal arrays of nanometer-sized cylindrical pores. It is shown that this material can be synthesized by cooperative condensation of silicate and cylindrical cationic micelles. Careful control of the surfactant-water content and the rate of condensation of silica at high alkalinity resulted in hollow tubules 0.3 to 3 micro...
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ژورنال
عنوان ژورنال: World Journal of Nano Science and Engineering
سال: 2012
ISSN: 2161-4954,2161-4962
DOI: 10.4236/wjnse.2012.23017