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 Sb₂O₃ 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 Sb₂O₃. Physical characterizations reveal the introduced orthorhombic Sb₂O₃ greatly contributes to improving the active phases and inhibiting the disadvantageous δ-VOPO₄ 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 1Sb₂O₃–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.