Synthesis and physicochemical properties of Zr-MCM-41 mesoporous molecular sieves and Pt/H{sub 3}PW{sub 12}O{sub 40}/Zr-MCM-41 catalysts

Journal Article · Mon Oct 15 04:00:00 EDT 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2007.08.023· OSTI ID:21049532

Wang, J A ^[1]; Norena, L E; Aguilar, J ^[2]; Navarrete, J; Salas, P; Montoya, J A; Del Angel, P ^[3]

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1. Escuela Superior de Ingenieria Quimica e Industrias Extractivas, Instituto Politecnico Nacional, Col. Zacatenco, 07738 Mexico D.F. (Mexico)
2. Departamento de Ciencias Basicas, Universidad Autonoma Metropolitana-A, Av. San Pablo No. 180, 02200 Mexico D.F. (Mexico)
3. Instituto Mexicano del Petroleo, Programa de Ingenieria Molecular, Eje Central Lazaro Cardenas No. 152, 07730 Mexico D.F. (Mexico)

For the first time, modifications of the surface and framework of Si-MCM-41 by depositing a heteropolyacid on the surface and by introducing foreign Zr{sup 4+} ions into the framework are investigated. The Zr-modified Si-MCM-41 mesoporous materials (hereafter referred as WSZn, n=Si/Zr=25, 15, 8, 4) were synthesized through a surfactant-templated preparation approach, using low-cost fumed silica as the Si precursor. After impregnation with 25 wt% of H{sub 3}PW{sub 12}O{sub 40}, the surface Broensted acidity of the Pt/H{sub 3}PW{sub 12}O{sub 40}/WSZn catalysts was greatly enhanced by 2-10 times relative to the bare WSZn support. Two kinds of supported heteropolyacids were formed: (i) bulk-like heteropolyacid crystals with unchanged Keggin structures, and (ii) highly dispersed heteropolyacid with distorted Keggin units. The formation of various kinds of heteropolyacid structures is closely related to the interaction between the heteropolyanions and the hydroxyl groups in the host support. - Graphical abstract: Modifications of the surface and framework of Si-MCM-41 by depositing a heteropolyacid on the surface and by introducing foreign Zr{sup 4+} ions into the framework are investigated. Broensted acidity of the Pt/H{sub 3}PW{sub 12}O{sub 40}/Zr-MCM-41 catalysts was greatly enhanced by 2-10 times relative to the bare Zr-MCM-41 support.

• OSTI ID: 21049532
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 10 Vol. 180; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CATALYSTS
CRYSTALS
HETEROPOLYANIONS
HYDROXIDES
MOLECULAR SIEVES
PH VALUE
PRECURSOR
SILICA
SILICON
SURFACES
SURFACTANTS
SYNTHESIS
ZIRCONIUM
ZIRCONIUM IONS