Synergistic Ni-MoO3 Redox Catalysis in MIL-101(Cr) for Efficient H2O2 Activation and Ultra-Deep Desulfurization.

In this study, a novel Ni-MoO3@MIL-101(Cr) composite catalyst was synthesized via a one-step hydrothermal method for the oxidative desulfurization (ODS) of dibenzothiophene (DBT). The catalyst combines the high specific surface area of MIL-101(Cr) with the redox properties of Ni-MoO3, providing an effective synergy between adsorption and catalytic oxidation. The incorporation of Ni as a promoter significantly enhances catalytic activity, enabling complete sulfur removal (∼100%) under mild conditions (50 °C) within 60 min. Structural characterizations (scanning electron microscopy, X-ray diffraction, and SAED) reveal that the catalyst retains its nanosheet-nanorod morphology and crystalline MoO3 phase after repeated use, with only a slight decrease in the crystallinity of the MIL-101(Cr) framework. Mechanistic analyses using X-ray photoelectron spectroscopy, Raman, and temperature-programmed reduction demonstrate that surface oxygen vacancies and Lewis acid sites promote ODS activity, while highly dispersed Ni-MoO3 species facilitate H2O2 activation and Mo6+/Mo5+ redox cycling, leading to efficient generation of reactive oxygen species. The catalyst also exhibits excellent stability, maintaining 98.7% DBT conversion after five cycles. These results demonstrate that the strong Ni-Mo synergistic effect and efficient oxygen activation make Ni-MoO3@MIL-101(Cr) a robust and highly efficient catalyst for deep fuel desulfurization.