H3PW12O40 supported on mesoporous MCM-41 and Al-MCM-41 materials: preparation and characterisation

MCM-41 and Al–MCM-41 has been synthesizedusing cetyl-trimethylammonium bromide (CTAB)surfactant as template and adding the silica precursor toaqueous solutions containing CTAB. The obtained solidswere calcined at 600 C for 4 h. HPW heteropolyacidsupported on the mesoporous were prepared using theincipient wetness method. The characterization of materialswas performed by X-ray diffraction, TransmissionElectron Microscopy, N2 adsorption, 29Si Cross Polarization–Magic Angle Spinning and 27Al MAS NMR. Resultsshowed that the hexagonal structure is obtained in bothcases. The Aluminium species are located inside an extraframework.The impregnation reduces the surface area ofthe mesoporous materials especially of the Al–MCM-41suggesting a participation of aluminium during theimpregnation. HPW is well dispersed in the mesoporousmaterials and is located inside the pores interacting withthe silanol group of the pores wall. 27Al MAS NMRmeasurements have showed that the impregnation causesthe removal of the non-framework aluminium.