Preparation, characterization and catalytic activity of mesoporous Ag2HPW12O40/SBA-15 and Ag2HPW12O40/TiO2 composites

The current study reports the synthesis and characterization of tungstophosphoric acid and its acid silver salt supported on mesoporous molecular sieve SBA-15 and TiO2. Because silver salts are partially insoluble, the SBA-15 and TiO2 supported silver acid salts were prepared by two step sequential impregnations. The synthesized catalysts were characterized by various physicochemical methods such as Fourier transform infrared and Raman spectroscopy, differential thermal analysis, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy and nitrogen physisorption at -196 degrees C. It is observed that both active phases keep their Keggin-type structure after being supported on the supports while their specific surface area is considerably increased by deposition on mesoporous substrates. The results also indicated that the synthesized catalysts retained the morphology specific for each of the supports, while their thermal stability is increased in comparison with their active phases. The catalytic activity of the prepared catalysts was probed for the vapor phase dehydration of ethanol at 300 degrees C. Results revealed that all the catalysts show considerably improved catalytic activity in comparison to the bulk active phases.