Precision-Oriented Crystal Engineering of Vanadium–Phosphorus Oxides Catalysts: Unlocking Multi-Effect Performance in Selective Oxidation

Vanadium–phosphorus oxides (VPO) represent a family of complex mixed-metal oxides with structurally diverse crystalline phases, among which (VO)2P2O7 serves as the predominant active phase in the selective oxidation of n-butane to maleic anhydride (MA) and in ammonia oxidation. The catalytic activity, selectivity, and long-term stability are critically governed by crystal structure features, such as phase composition, lattice defects, and structural dynamics under reaction conditions. Based on this, this review systematically summarizes the crystallographic evolution of VPO catalysts, encompassing their historical development, synthesis methods, and structural characterization. Emphasis is placed on the relationship between the crystal structure and catalytic performance, especially in the context of n-butane oxidation. The mechanisms of phase transformation among different VPO crystalline forms are thoroughly discussed, offering insight into how structural evolution affects the catalytic behavior. Additionally, this review highlights advanced strategies for modulating the phase composition and enhancing the stability of VPO catalysts, including doping, redox treatments, and morphology control, which collectively contribute to the design of “tailored” catalysts that balance high conversion rates with excellent selectivity. Finally, future research directions are proposed, including in situ and operando studies, multiscale modeling, and advanced synthetic techniques, to drive the development of next-generation VPO catalysts for efficient and sustainable selective oxidation applications.