Synthesis and acidic catalytic properties of ordered mesoporous alumina-tungstophosphoric acid compositesElectronic supplementary information (ESI) available: TGA profile of tungstophosphoric acid and XRD patterns of mesoporous alumina and Al-HPW(w) composites. See DOI: 10.1039/c0jm01283a

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 p 6 mm pore structure with uniform large pores. The mesoscopic order of these structures was evidenced by SAXS analysis, TEM images and N 2 physisorption measurements. The composite materials exhibited BET surface areas in the range of 54-71 m 2 g −1 , total pore volumes in the range of 0.11-0.14 cm 3 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 alumina-HPW 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. A series of mesoporous alumina-tungstophosphoric acid composite frameworks with tunable composition (5-53 wt% in HPW) and ordered pore structure was synthesized. These mesoporous surfaces exhibited high stability and exceptional acidic catalytic activity.