Synthesis of CdS hollow spheres coupled with g-C3N4 as efficient visible-light-driven photocatalysts

CdS hollow spheres (CdS HS) coupled with graphitic carbon nitride (g-C3N4) photocatalysts are synthesized and characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible diffuse reflection spectroscopy (DRS), x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and photoluminescence spectroscopy (PL). The effect of CdS content on CdS HS/g-C3N4 activity is investigated by  the degradation of Rhodamine B (RhB). The sample of 20 wt% CdS content shows the best photocatalytic performance under visible-light irradiation, with the corresponding RhB degradation rate reaching 97.3%. The excellent photoactivity of CdS HS/g-C3N4 is attributed to the synergistic effect of g-C3N4 and CdS HS. A possible photocatalytic mechanism of the CdS HS/g-C3N4 composite is proposed and corroborated by PL.