Increasing maleic anhydride selectivity for n-butane oxidation by Y-modified VPO catalysts

• Y-modified VPO catalyst is firstly used to the selective oxidation of n -butane. • A moderate amount of acidity is beneficial to the selective oxidation of n -butane. • The MA selectivity depends on the acidity and the content of lattice oxygen of the VPO catalyst. In the present study, a series of VPO catalysts with different amount of Y were prepared by organic phase method and activated in butane-air atmosphere. The catalytic performance was tested by the selective oxidation of n -butane to maleic anhydride (MA). The catalysts were characterized by SEM, TG, XRD, Raman, XPS, H 2 -TPR and NH 3 -TPD techniques. The characterization results showed that the addition of appropriate amount of Y can increase the amount and stability of the rose-like flower clusters of VPO precursors. Meanwhile, the addition of Y greatly increased the proportion of lattice oxygen on catalyst surface and changed the surface acidity of VPO catalyst. As a result, the selectivity and yield of MA were greatly improved by introducing the right amount of Y.