Issue 39, 2010

Synthesis and acidic catalytic properties of ordered mesoporous alumina–tungstophosphoric acid composites

Abstract

A series of well-ordered mesoporous alumina–tungstophosphoric (HPW) acid composite frameworks has been prepared by a sol–gel copolymerization route in the presence of non-ionic surfactants. The resulting materials feature a high loading of HPW acids (up to ∼53 wt%) in composite framework and possess hexagonal p6mm pore structure with uniform large pores. The mesoscopic order of these structures was evidenced by SAXS analysis, TEM images and N2 physisorption measurements. The composite materials exhibited BET surface areas in the range of 54–71 m2 g−1, total pore volumes in the range of 0.11–0.14 cm3 g−1 and quite narrow pore size distributions with peak maxima in the 7.1–8.3 nm range. The Keggin clusters were incorporated in mesoporous alumina walls by strong chemical bonds according to the FT-IR and UV/vis spectroscopy analysis. This chemical linkage of HPW to the alumina matrix is responsible for the outstanding stability of these materials against water-leaching. The mesoporous surfaces exhibited exceptional acidity that arises from the unique aluminaHPW composite structure. As the loading of HPW increases, the surface acidic character of the composites enhanced, and this is reflected in the higher catalytic activity towards isopropanol conversion.

Graphical abstract: Synthesis and acidic catalytic properties of ordered mesoporous alumina–tungstophosphoric acid composites

Supplementary files

Article information

Article type
Paper
Submitted
02 May 2010
Accepted
05 Aug 2010
First published
08 Sep 2010

J. Mater. Chem., 2010,20, 8631-8638

Synthesis and acidic catalytic properties of ordered mesoporous aluminatungstophosphoric acid composites

G. S. Armatas, A. P. Katsoulidis, D. E. Petrakis and P. J. Pomonis, J. Mater. Chem., 2010, 20, 8631 DOI: 10.1039/C0JM01283A

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