Revisiting the construction of graphene-CdS nanocomposites as efficient visible-light-driven photocatalysts for selective organic transformation

The cadmium sulfide (CdS) microsphere decorated graphene (GR) nanocomposite (GR-CdS) was prepared by a facile hydrothermal approach in which CdS ingredients were closely enwrapped by the GR scaffold. The GR-CdS nanocomposite was subjected to a number of characterizations including X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), field emission scanning electron microscopy (FESEM), transmission scanning electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). It was found that integration of CdS microspheres with two-dimensional GR scaffolds exerts a profound influence on the properties of hybrid nanocomposites, such as optical and electronic nature along with morphology. Photocatalytic performances of the GR-CdS nanocomposites were evaluated by selective organic transformation under mild conditions. The results demonstrate that the GR-CdS nanocomposite can serve as an efficient visible-light-driven photocatalyst for the selective oxidation of benzyl alcohol to benzaldehyde under ambient conditions. The significantly enhanced photocatalytic performance of GR-CdS nanocomposites can be attributed to the synergistic effect of enhanced light absorption intensity and high electron conductivity of GR, which facilitates charge separation and lengthens the lifetime of photogenerated electron-hole pairs. Moreover, photocatalytic performances of various GR-CdS nanocomposites featuring different degrees of interfacial contact between GR and CdS were also systematically explored. It is anticipated that our work could enrich the information on the preparation of narrow bandgap semiconductor/GR hybrid nanocomposites for a wide range of photocatalytic applications.