Dispersing TiO2 Nanoparticles on Graphite Carbon for an Enhanced Catalytic Oxidative Desulfurization Performance

Metal oxide nanoparticles (NPs) have been regarded as highly active species for many catalytic processes but are being seriously hindered by their agglomeration property. In this work, graphite carbon (GC) is employed as a carrier for the dispersion and stabilization of TiO2 NPs to overcome the disadvantage. A series of supported catalysts TiO2/GC with different loading amounts of TiO2 are prepared and characterized in detail. It is discovered that TiO2 NPs are well dispersed on GC when the loading amount is 10%, which is confirmed by elemental mapping and transmission electron microscopy images. As expected, the supported 10%-TiO2/GC catalyst reveals outstanding catalytic activity in the oxidative removal of dibenzothiophene (DBT). A 100% desulfurization efficiency is obtained under mild reaction parameters. Meanwhile, the kinetic parameter investigation shows that the oxidation of DBT followed the pseudo-first-order kinetic model. In addition, the mechanism of the oxidative desulfurization system is studied carefully by free-radical scavenging experiments, electron spin resonance, Raman spectroscopy, and gas chromatography–mass spectrometry analysis. Moreover, the supported catalyst possesses excellent stability and recycling performance, and the removal of DBT remains to be >99% after five times of recycling.