制备方法对钒磷氧复合氧化物晶相和比表面积的影响

The Effects of Preparation Methods on the Crystal Phase and Specific Surface Area of VPO Catalysts

采用水相、有机相及球磨法等不同方法制备了VPO催化剂,使用BET、XRD等测试手段对VPO催化剂的比表面积、晶相结构进行了表征.研究发现水相法制备时,比表面积较小,晶相较复杂,焙烧温度升高,结晶度增加.有机相和球磨法制备时,催化剂的比表面积较大,晶相几乎为(VO)2P2O7,在超临界条件下干燥,可使所有催化剂比表面积显著增大,晶相更完善.

VPO catalysts were prepared by four methods. BET, XRD techniques were used to investigate the effects of different preparation methods on the phase composition and specific surface area of VPO catalysts. The results indicated that the VPO catalysts have lower specific surface area and complex crystal phase on water medium. The higher temperature of calcination can decrease surface area and increase crystallinity. In organic medium and ball mill, catalysts have larger specific surface area and an active phase(VO)\-2P\-2O\-7 . Through the supercritical fluid drying (SCFD) process the specific surface area of catalyst was increased notably and better crystal phase.