Role of Cerium-Layered Double Hydroxide-Derived Oxide Dopants in Vanadium Phosphorus Oxide for Selective Oxidation of n-Butane

Abstract

The selective oxidation of n-butane to maleic anhydride by vanadium phosphorus oxide (VPO) catalyst plays an important role in the high-value utilization of low-carbon alkanes. In the present work, the effect of doping VPO with cerium-layered double-hydroxide-derived oxide (Ce-LDO) on the catalytic performance in selective oxidation of n-butane was investigated. XRD, Raman, SEM, XPS, EPR, NH₃-TPD and pyridine-IR characterizations were performed on the catalysts to understand the mechanism of the promotion effects of Ce-LDO. The doping of Ce-LDO to VPO increases the n-butane conversion by 20% and the molar yield of maleic anhydride by approximately 10%, suggesting that the synergistic effect of Ce-LDO in acid–base and electronic properties could significantly enhance the catalytic performance of VPO. The addition of layered double hydroxides (LDOs) increases the amount of active crystal plane and density of acid site at VPO surface which lead to higher conversion of n-butane but lower selectivity toward MA. Further addition of Ce increases the relative amount of surface V⁴⁺ phase and promotes the mobility of surface lattice oxygen, benefiting the formation of MA. This work provides new insights for the VPO catalyst design and optimization for industrial production of maleic anhydride.