Cyclohexane oxidative dehydrogenation represents a green and promising route for cyclohexene production with a broad industrial potential. However, previous studies have largely focused on conventional metal oxide catalysts or a narrow range of support morphologies, and the effect of the ceria morphology on the catalytic performance remains insufficiently understood. In particular, the role of vanadium species supported on ceria with distinct three-dimensional architectures has not been comprehensively investigated. Here, a series of VOx/CeO2 catalysts were synthesized by anchoring VOx species onto cubic, plate-like, and wire-like CeO2 supports via a liquid-phase chemical grafting strategy to unravel the morphology-dependent structure–activity relationship in cyclohexane oxidative dehydrogenation. The results demonstrate pronounced morphology-dependent strong metal–support interactions (SMSI) between VOx and CeO2. Raman and XPS analyses identify the formation of V–O–Ce bonds accompanied by increased Ce3+ content and surface-adsorbed oxygen, whereas EPR and H2-TPR confirm enhanced oxygen vacancies and low-temperature reducibility, thereby facilitating oxygen migration and redox reversibility. Notably, cubic CeO2 exhibits the strongest SMSI features, delivering a higher cyclohexene yield than its plate-like and wire-like counterparts, along with excellent stability over 96 h of continuous operation. Mechanistic investigations reveal that cyclohexane ODH simultaneously follows the lattice-oxygen-mediated Mars-van Krevelen pathway and the radical process driven by surface-active oxygen species.
Liu et al. (Mon,) studied this question.