Synthesis of Tunable-Acidity Vanadium Phosphorus Oxide CatalystsModified by Layered Double Oxide for the Selective Oxidation ofn-Butane

A series of tunable-acidity vanadium phosphorus oxide (VPO) catalysts modified by layered double oxide (LDO)werefirst fabricated by a mechanical milling approach. The optimum Zn2Mg1Al1O-VPO sample achieved 63.2% yield of maleicanhydride (MA), which is 8.9% higher than that of Blank-VPO. Various characterizations were used to explore the relationshipbetween the surface properties such as the crystal structure, surface P/V ratio, surface acidity, and catalytic performance. The NH3-TPD and pyridine IR analysis demonstrated that the appropriate surface acidity could significantly improve the performance of theVPO catalyst. A synergistic catalysis mechanism between the Lewis and Bronsted acid sites is tentatively proposed to enhance thecatalytic performance of VPO. The Lewis acid sites accelerate the C-H bond activation and cleavage, thereby increasing theconversion ofn-butane. Moreover, the Bronsted acid sites can stabilize the reaction intermediates and facilitate the desorption ofMA, consequently improving the selectivity of MA.

Automated summary

A series of tunable-acidity VPO catalysts modified by LDO were fabricated, and the relationship between the surface properties and catalytic performance was explored. The appropriate surface acidity significantly improved the performance, and a synergistic catalysis mechanism between Lewis and Bronsted acid sites was proposed to enhance the catalytic performance.