Abstract:
A series of phosphomolybdic acid (5-20 wt % PMA) promoted zirconia-ceria (ZrO2-CeO2) mixed oxides were synthesized by an impregnation method and characterized by XRD, nitrogen adsorption/desorption, UV-vis DR spectroscopy, TPR/TPD, and P-31 MAS NMR spectroscopy. NMR spectra revealed that the catalyst retained the Keggin structure of PMA even after calcination at 500 degrees C. The catalysts were screened for the solvent-free liquid-phase oxidation of benzyl alcohols using hydrogen peroxide as the oxidizing agent. The sample of 15 wt % PMA/ZrO2-CeO2 showed 85% conversion and 96% selectivity to the corresponding aldehydes.