Enhancing the Performance of Vanadium–Phosphorus Oxide Catalysts for n-Butane Oxidation by Tuning the P/V Ratio and Incorporating Y Additives

Vanadium–phosphorus oxide (VPO) catalysts are extensively utilized in industrial processes for the selective oxidation of n-butane to maleic anhydride. Despite their industrial success, challenges persist in enhancing n-butane conversion while maintaining high selectivity. This study synthesized and characterized two catalyst series to investigate how the P/V ratio and Y additive influence catalyst performance. Specifically, variations in the P/V ratio significantly influence the crystallite size of the catalyst, the specific surface area, the ratio of lattice oxygen to surface oxygen, and the formation of different V⁵⁺ species, with the optimum performance obtained at a P/V ratio of 0.95. The incorporation of Y additives inhibits grain agglomeration and the formation of VOPO₄, and it enhances the reducibility of lattice oxygen, thereby increasing the catalytic activity. By elucidating the roles of the P/V ratio and Y additives, this study offers valuable insights for the rational design of more efficient catalytic systems for n-butane oxidation.