Synergistic Mixed Carbide Catalysts for Accelerated Aerobic Oxidative Desulfurization of Fuels

Aerobic oxidative desulfurization (AODS) is a promising technique for clean fuels production. Herein we present synergistic mixed carbide catalysts (FeMoWC) synthesized rapidly by microwave irradiation for AODS process. The combination of a ternary mixture of carbides for AODS leads to a significant increase in catalytic activity compared to single-phase, dicarbides or simply oxides of transition metals. The synthesized materials were characterized in detail by a complex of methods: XRD, HRTEM, EDX, SEM, XPS, low-temperature nitrogen adsorption/desorption, H2-temperature-programmed reduction (TPR), Raman spectroscopy. Under selected conditions (150 °C, 6 atm, 0.5 wt % catalyst dosage) complete oxidation of dibenzothiophene (DBT) was achieved in just 20 min. Under optimal conditions, the specific catalytic activity was 12.73 and 293.43 mmol g–1 h–1 for the model and real fuel, respectively. A possible mechanism for the reaction is discussed, including the activation of atmospheric oxygen with the formation of a superoxide radical, the formation of alkyl peroxides and peroxo complexes. The proposed approaches open up wide possibilities for the future development of highly efficient AODS catalysts for practical application and production of clean motor fuels.