Cobalt-Doped g-C3N4 as Efficient Catalyst for Oxidative Desulfurization of Fuel Oil

Co₃O₄/g-C₃N₄ supported catalysts with different Co₃O₄ contents were synthesized using the impregnation method followed by high-temperature calcination. The structure and properties of the supported catalysts were characterized through Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), N₂ adsorption-desorption (BET), and thermogravimetric analysis (TGA). In this experiment, Co₃O₄/g-C₃N₄ was utilized as the catalyst, H₂O₂ served as the oxidant, and a co-crystal solvent [(polyethyleneglycol-200) : (tetrabutylammonium chloride) = 2 : 1] was employed as the extractant for the oxidative desulfurization of model oil. The impact of different loadings, reaction temperatures, oxygen-sulfur ratios, catalyst dosages, and types of sulfides on the desulfurization rate were systematically investigated. The results demonstrate that under optimal conditions of T = 50°C, m(catalyst) = 0.03 g, and n(O)/n(S) = 10, the desulfurization rate of the 30%Co₃O₄/g-C₃N₄ catalyst can reach 93.6±0.5% after a reaction time of 75 min. After five cycles of recycling, the catalytic activity of the catalyst exhibited no significant decrease.