A Ce–Mo–O catalyst prepared by a simple sol–gel method was proved to be highly active for aerobic oxidative desulfurization. Almost complete conversions of dibenzothiophene and 4,6-dimethyldibenzothiophene were achieved without any additional sacrificial agent at 100 °C and atmospheric pressure, and the conversion of benzothiophene could reach 97%. Reusability of the catalyst was also conducted, and >99% conversions could be achieved in three consecutive runs. As supported by carefully-designed control experiments, oxygen was activated by Ce species in the catalyst first, forming some reactive oxygen species, which oxidized DBT into DBTO₂ with the assistance of Mo species. Furthermore, selective quenching experiments indicated the generation of superoxide species during the reaction.

Hollow Silicalite-1 and ZSM-5 zeolites with hierarchical porous shells have been synthesized by using a dissolution-recrystallization method. The morphology, structure, and acidity of these zeolites supported Pt catalysts were characterized by XRD, FT-IR, MAS-SSNMR, FE-SEM, FE-TEM, N₂-BET, XPS, NH₃-TPD, and CO pulse chemisorption. Compared to the conventional ZSM-5 supported Pt catalyst, the special structure in hollow ZSM-5 zeolite significantly promotes the dispersion of metallic Pt and the synergistic effect between metal active sites and acid sites. These boost the catalytic activity, selectivity of guaiacol hydrodeoxygenation toward cycloalkanes and long-term stability over the Pt/hollow ZSM-5 catalyst combined with improved mass transfer of products and reactants derived from the hierarchical hollow porous structure. Moreover, the Pt/hollow ZSM-5 catalyst exhibits excellent low temperature catalytic activity to completely transform guaiacol into cycloalkanes with the cyclohexane selectivity of more than 93% at 220 °C, suggesting that hollow ZSM-5 zeolite is a promising support for upgrading of bio-oils.

The hydroconversion of waste cooking oil into hydrocarbon fuel was investigated over the hierarchical USY zeolite-supported NiMo catalysts which were prepared by dealumination ((NH₄)₂SiF₆)/desilication (NaOH). The physical and acidity properties of the hierarchical catalysts were characterized by X-ray diffraction (XRD), the Brunauer-Emmett-Teller (BET) infrared spectroscopy of adsorbed pyridine (Py-IR), ammonia temperature-programmed desorption (NH₃-TPD), and H₂ temperature-programmed reduction (H₂-TPR). The Brønsted/Lewis (B/L) acid distribution was little affected by dealumination and the acid density decreased significantly. However, the highly-desilicated catalysts decreased the B/L ratio obviously. Therefore, many more Mo species in the NiMoO₄⁻ and MoO₃ phases were produced in the AHFS-treated catalysts, while more high-valence-state Mo species in the NiMoO₄⁻ phase were formed in the NaOH-treated catalysts. The AHFS-treated catalysts showed higher catalytic activity and better DCO₂ selectivity and selective cracking for jet fuel. The 42.3% selectivity of jet fuel and 13.5% selectivity of jet-range aromatics was achieved over the 8 wt % (NH₄)₂SiF₆-treated catalyst with 67% DCO₂ selectivity.

A hierarchical SBUY-MCM-41 catalyst was prepared by sacrificing USY (a microporous molecular sieve) to synthesize the MCM-41 zeolite via a hydrothermal method. The hydroconversion of waste cooking oil into hydrocarbon fuel over a NiMo/SBUY-MCM-41 catalyst was investigated. The micropores of the Y building units were inherited by the SBUY-MCM-41 zeolite, in which a special hierarchical structure was formed and the accessibility of reactants to the micropore active sites was improved. The hierarchical SBUY-MCM-41 showed high acidity and hydrothermal stability. Compared with mesoporous Al-MCM-41 and microporous USY zeolites, the SBUY-MCM-41-supported NiMo catalyst significantly enhanced the selective cracking of waste cooking oil for the production of jet-fuel-range hydrocarbons (37.3%), with the highest selectivity for the formation of C₁₀–C₁₄ hydrocarbons and a satisfactory selectivity for the formation of jet-fuel-range aromatics (7.6%), as well as a few cyclic compounds. The improved selectivity is the result of the special hierarchical structure and acid distribution of SBUY-MCM-41. This work provides a new strategy to synthesize a hierarchical catalyst for producing alternative jet fuel from waste cooking oil and vegetable oils.