Effects of the Doping ZnO on the property of Magnetic Solid Acid SO/sub 4/sup 2-/ZrO/sub 2-/Fe/sub 3/O/sub 4/

Two kinds of magnetic solid acid catalysts are prepared via a simple chemical co-precipitation approach. The obtained materials are characterized by X-ray Diffraction, FT-IR Spectrometer, Different Scanning Calorimetry, Vibrating Sample Magnetometer, Transmission Electron Microscopy, High-resolution Transmission Electron Microscopy and Hammett indicator. The results indicate that the doping of ZnO restrains the phase transformation from tetragonal zirconia to monoclinic zirconia. Furthermore, the samples show a magnetic behavior. Saturation magnetization of the sample SO/sub 4//sup 2-/ /ZrO/sub 2/-Fe/sub 3/O/sub 4/ is smaller than SO/sub 4/sup 2/-/ZrO/sub 2/-Fe/sub 3/O/sub 4/-ZnO; Transmission Electron Microscopy results indicate that the increasing ZnO makes the grains size considerably smaller, and the High-resolution Transmission Electron Microscopy shows that the doping of ZnO maintains the desired tetragonal zirconia phase, and the interplanar spacing is d(101)=0.29 nm. Hammett indicator results show that the acid strength becomes stronger because of the doping of ZnO. The synthesis of methyl laurate as the probe reactions of magnetic solid acids is studied, and the result indicates that the doping of ZnO delays the deactivation rate of catalysts. (author)