负载型钒基催化剂上丙烷的氧化脱氢──酸碱性及氧化还原性质对催化性能的影响

Abstract

用乙酰丙酮络钒法制备了两组不同氧化物和磷酸盐载体负载的钒载量为5%V2O5的催化剂.Xrd和rAMAn光谱表征结果表明，钒氧化物在载体MgO，Al2O3，Mg3（PO4）2，AlPO4和zr3（PO4）4上是高度分散的，没有生成明显的V2O5晶相；催化剂的可还原性与其氧化物或磷酸盐载体的金属还原电位序有较好的对应关系，与其丙烷氧化脱氢活性也存在较好的平行关系，表明钒氧化物与载体的阳离子形成了V—O—M桥键，该桥键氧较易移去，可能是丙烷氧化脱氢的活性氧物种；催化剂表面酸性位有利于丙烷C—H键的活化，但导致深度氧化产物增多.

The supported vanadia based, 5%V 2O 5/support (MgO, Al 2O 3, Mg 3(PO 4) 2 , AlPO 4 and Zr 3(PO 4) 4 ) catalysts were prepared.X ray diFFraction pattern and Raman spectroscopy characterization showed that vanadia was highly dispersed on the supports.The activity For propane oxidative dehydrogenation is parallel to the reducibility of the catalysts.And the surFace acid sites are Favorable to activate the 2° C—H bond in propane molecule, which can decrease the propene selectivity in the same time.The bridge lattice oxygen (V—O—M) may be the active oxygen species in the propane oxidative dehydrogenation.