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Highly dispersed heteropolyacids supported on modified MCM 41 mesoporous materials

A. POPA1,* , V. SASCA1, E.E. KIŠ2, RADMILA MARINKOVIĆ-NEDUČIN2, J. HALASZ3

Affiliation

  1. Institute of Chemistry Timişoara, Bl.Mihai Viteazul 24, 300223 Timisoara, Romania
  2. University of Novi Sad, Faculty of Technology, Cara Lazara 1, Novi Sad, Serbia
  3. University of Szeged, Dep.of Applied and Environmental Chemistry, Rerrich ter 1, H-6720 Szeged, Hungary

Abstract

Solid acid catalysts consisting of heteropolyacids (HPAs) H3PMo12O40 (HPM) and H4PVMo11O40 (HPVM) supported on mesoporous pure-silica molecular sieve MCM-41 and modified molecular sieves Al-MCM-41 and Fe-MCM-41 have been prepared and characterized by XRD, FT-IR, 31P MAS NMR, low temperature nitrogen adsorption and scanning electron microscopy. All supported HPAs were prepared by impregnation using the incipient wetness techniques with a mixture water: ethanol = 1:1. FT-IR studies showed that HPAs anions preserved their Keggin structure after deposition on pure and modified molecular sieves supports. X-ray diffraction and SEM studies confirmed the uniformity of the distribution of active phase in the supported samples. The values of specific surface area of both HPAs were increased by deposition on molecular sieve supports. It is found that most of HPM and HPVM (active phases) in supported samples are well dispersed on the support and MCM-41 supported HPAs still keep its Keggin structure. The surface morphology of the MCM-41 supported samples is almost similar to that of MCM-41 support. A relatively uniform distribution of active phase in the support pores was evidenced by EDS analysis..

Keywords

Heteropolyacids, Molecular sieves, Texture, structure, BET, SEM, XRD, 31P MAS NMR.

Submitted at: May 12, 2008
Accepted at: June 9, 2008

Citation

A. POPA, V. SASCA, E.E. KIŠ, RADMILA MARINKOVIĆ-NEDUČIN, J. HALASZ, Highly dispersed heteropolyacids supported on modified MCM 41 mesoporous materials, Journal of Optoelectronics and Advanced Materials Vol. 10, Iss. 6, pp. 1401-1407 (2008)