丙烷氧化脱氢VMgO催化剂活性位的研究

Abstract

应用低温EPr等方法对比研究了浸渍法和硝酸盐法制备的两个系列VMgO催化剂的活性位.结果表明，只有在合适的制备条件下，生成了适量V4＋离子的钒酸镁物相才具有较好的催化活性，含有适量V4＋离子的正、焦钒酸镁可能是丙烷氧化脱氢制丙烯VMgO催化剂的活性相.含有V4＋的Mg3V2O8活性相的表面活性位结构可能为V4＋-O-Mg-O-V5＋，含有V4＋的α-Mg2V2O7活性相的表面活性位结构可能为V4＋-O-V5＋.

The active sites of VMgO catalysts prepared by impregnation and nitrate methods were investigated.The results indicated that only the Mg vanadates containing proper amount of V4+ions produced under the suitable preparation conditions demonstrated better catalytic activities, and thus Mg orthovanadate and pyrovanadate with proper amount of V4+ may be the active phases of VMgO catalysts For oxidative dehydrogenation of propane to propene.The surFace active site structure of Mg3V2O8 with V4+may be V4+OMgOV5+, and that of αMg2V2O7 with V4+ may be V4+OV5+.