Regulation of Maleic Anhydride Selectivity for n-Butane Oxidation by Sb₂O₃-Modified Vanadium Phosphorus Oxide Catalysts

Abstract

Maleic anhydride (MA) is a significant chemical raw material to produce industrial products. Vanadium phosphorus oxide (VPO) catalyst is considered an excellent catalyst for the selective oxidation of n-butane to prepare MA. However, MA selectivity is still limited by the complex crystalline phases and morphological characteristics of VPO catalysts. Herein, orthorhombic Sb 2 O 3 was proposed as a structural directing agent and electronic promoting agent to modify the VPO catalyst. The relationship between the structure and the catalytic performance was systematically investigated to reveal the effect of orthorhombic Sb 2 O 3 . Physical characterizations reveal the introduced orthorhombic Sb 2 O 3 greatly contributes to improving the active phases and inhibiting the disadvantageous δ-VOPO 4 phase. Besides, the active phase and surface chemical properties of the VPO catalyst are effectively regulated, which is beneficial to the selective oxidation of n-butane. As expected, the optimal 1Sb 2 O 3 −O@VPO catalyst demonstrates considerable n-butane conversion, MA selectivity, and MA yield. This work should open a feasible way to prepare efficient VPO catalysts for industrial catalysis.