Studied On Modification Of MOFs-based Photocatalyst And Its Desulfurization Performances

The combustion of sulfur-containing compounds in fuel oil is one of the main sources of air pollution,so it is imperative to obtain low-sulfur or even non-sulfurized fuel oil.As a new green desulfurization technology,photocatalytic oxidative desulfurization has attracted more and more researchers'attention.However,the preparation of an excellent photocatalytic oxidative desulfurization catalyst is key technology.In this paper,a series of catalysts based on MOFs are designed and used in the photocatalytic oxidative desulfurization of fuel oil.Firstly,a series of composite photocatalysts CeO₂/MIL-101?Fe?were successfully synthesized by a solvothermal method.And,the physico-chemical properties of the materials were characterized by some technology,including X-ray diffraction?XRD?,Fourier infrared spectroscopy?FT-IR?,scanning electron microscope?SEM?,projection electron microscope?TEM?,X-ray photoelectron spectroscopy?XPS?,ultraviolet-visible diffuse reflection?UV-vis DRS?,fluorescence spectroscopy?PL?,capture experiments and N₂ adsorption and desorption curves.The result found that the surface of MIL-101?Fe?was uniformly decorated by some small-crystal CeO₂ and its morphology remain regular.In addition,a appropriate band gap was formed between MIL-101?Fe?and CeO₂ phases.Under visible light irradiation,the evaluation results of dibenzothiophene?DBT?removal showed,when the introduction amount of CeO₂ was 60 mg,the prepared catalyst 60mg-CeO₂/MIL-101?Fe?had an optimum desulfurization performance.The desulfurization rate reached 90%,which was much higher than that of the bare MIL-101?Fe?.The result demonstrated thet the successful introduction of CeO₂ reduces the band gap and the recombination rate of electron hole in the catalyst,thus improving the photocatalytic performance.The stability evaluation results illustrated that the photocatalytic desulfurization performance of the catalyst basically remained unchanged after 4 cycles.Secondly,a layered structure g-C₃N₄ was fabricated by a high-temperature calcination method in this paper,and then a series of composite photocatalyst g-C₃N₄/MIL-101?Fe?were prepared by adjusting the introducting amount of g-C₃N₄.The physico-chemical properties of the samples were analyzed by XRD,FT-IR,SEM,TEM,XPS,UV-vis DRS,PL and N₂ adsorption and desorption.The results agreed that the phase MIL-101?Fe?remained orginal morphology with the addition of g-C₃N₄ in the composite,however,the its particle size and crystallinity were all decreased.The experimental results showed when the adding amount of g-C₃N₄ was 150 mg,the composite photocatalyst was provided with an appropriate band gap.And,150 mg-g-C₃N₄/MIL-101?Fe?presented a high desulfurization rate?92.2%?compared to that of pure MIL-101?Fe?or g-C₃N₄,respectively.The structure-activity relationship analysis decribed that a heterojunction structure was formed between g-C₃N₄ and MIL-101?Fe?,which accelerated the transfering of photogenerated electrons and reduced the recombination probability of electron-hole pairs,thus promoting the photocatalytic oxidation desulfurization performance.In addition,the composite photocatalyst had a good stability,whose desulfurization rate was only reduced by 8%after 4 cycles.