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

 
This item is provided by the institution :
University of Ioannina
Repository :
Repository of UOI Olympias
see the original item page
in the repository's web site and access all digital files if the item*
share



2010 (EN)
Synthesis and acidic catalytic properties of ordered mesoporous alumina-tungstophosphoric acid composites (EN)

Armatas, G. S. (EN)

Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας (EL)
Armatas, G. S. (EN)

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 similar 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 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. (EN)

heteropoly acid (EN)

Πανεπιστήμιο Ιωαννίνων (EL)
University of Ioannina (EN)

Journal of Materials Chemistry (EN)

English

2010

<Go to ISI>://000282223700028

The Royal Society of Chemistry (EN)



*Institutions are responsible for keeping their URLs functional (digital file, item page in repository site)