Carbon quantum dots/attapulgite nanocomposites with enhanced photocatalytic performance for desulfurization

Carbon quantum dots (CQDs)/attapulgite (ATP) nanocomposite was prepared by a simple impregnation method. The ATP was initially modified with hydrochloric acid solution, which favored for the combination of CQDs due to the generation of hydroxyl group on the surface. XRD shows the decrease of interplanar spacing of ATP (1 1 0) plane, suggesting that the CQDs are immobilized on the surface of ATP. UV–Vis shows that the absorption peak of modified ATP is apparently red-shifted and the absorbance intensity of CQDs/ATP is higher than others. FT-IR and XPS show that the CQDs are immobilized on the surface of ATP through hydroxylation reaction. TEM shows that the average diameter of CQDs nanoparticles is about 5 nm and they are coated on the surface of ATP uniformly. The CQDs/ATP nanocomposite was employed as catalyst for photocatalytic degradation of dibenzothiophene (DBT) in model gasoline under visible light irradiation. The influence of the mass ratio of CQDs to ATP on desulfurization performance was investigated. The desulfurization rate of DBT could reach 93% when the mass ratio of CQDs/ATP is 3:10. The enhanced photocatalytic oxidative desulfurization was attributed to the sensitizing effect and up-conversion property of CQDs.