Cesium heteropolysalts Cs3PMo12O40 and HCs3PVMo11O40 were synthesized by modifying the preparation conditions in order to get materials with a much higher surface area than the original Keggin-type heteropolyacids(H3P...Cesium heteropolysalts Cs3PMo12O40 and HCs3PVMo11O40 were synthesized by modifying the preparation conditions in order to get materials with a much higher surface area than the original Keggin-type heteropolyacids(H3PMo12O40 and H4PVMo11O40).These solids were used as carriers for the dispersion of H4PVMo11O40 heteropolyacid by the incipient wetness impregnation technique.The textural and structural properties of supports and catalysts were examined by scanning electron microscopy,N2 adsorption-desorption isotherms and Raman spectroscopy.The supported catalysts were studied before and after red/ox pretreatments by X-ray photoelectron spectroscopy,which showed that both the surface composition and oxidized to reduced species ratio depend on the used carrier.The catalytic performances of these novel supported catalysts in the selective oxidation of isobutane to methacrylic acid and methacrolein were studied.The best catalytic properties were obtained when H4PVMo11O40 was supported on HCs3PVMo11O40.The isobutane conversion and yield of the desired oxygenates increased along the unsupported H4PVMo11O40<H4PVMo11O40/Cs3PMo12O40<H4PVMo11O40/HCs3PVMo11O40 series.展开更多
文摘Cesium heteropolysalts Cs3PMo12O40 and HCs3PVMo11O40 were synthesized by modifying the preparation conditions in order to get materials with a much higher surface area than the original Keggin-type heteropolyacids(H3PMo12O40 and H4PVMo11O40).These solids were used as carriers for the dispersion of H4PVMo11O40 heteropolyacid by the incipient wetness impregnation technique.The textural and structural properties of supports and catalysts were examined by scanning electron microscopy,N2 adsorption-desorption isotherms and Raman spectroscopy.The supported catalysts were studied before and after red/ox pretreatments by X-ray photoelectron spectroscopy,which showed that both the surface composition and oxidized to reduced species ratio depend on the used carrier.The catalytic performances of these novel supported catalysts in the selective oxidation of isobutane to methacrylic acid and methacrolein were studied.The best catalytic properties were obtained when H4PVMo11O40 was supported on HCs3PVMo11O40.The isobutane conversion and yield of the desired oxygenates increased along the unsupported H4PVMo11O40<H4PVMo11O40/Cs3PMo12O40<H4PVMo11O40/HCs3PVMo11O40 series.
