Ultrasound exfoliation of g-C3N4 with assistance of cadmium ions and synthesis of CdS/g-C3N4 ultrathin nanosheets with efficient photocatalytic activity

•Ultrasound exfoliation strategy with assistance of Cadmium ion was used to synthesize CdS/g-C3N4 ultrathin nanosheets catalysts with visible light photocatalytic activity.•The synthesized CdS/g-C3N4 ultrathin nanosheets were confirmed by the X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet–visible diffuse reflection spectroscopy, Fourier transform infrared spectroscopy, and photoluminescence spectroscopy measurements.•The activity of ultrathin CdS/g-C3N4 photocatalyst are 2 and 1.4 times higher than that of CdS/g-C3N4 nanocomposite obtained by ultrasound exfoliation without assistance of Cadmium ion for the photocurrent intensity and degradation of methyl orange, respectively.•The mechanism for the photodegradation of methyl orange by ultrathin CdS/g-C3N4 photocatalyst was also investigated in this study.

Cadmium-assisted ultrasound exfoliation was used to synthesize CdS/g-C3N4 ultrathin nanosheet catalysts with visible-light photocatalytic activity. The samples showed enhanced photocatalytic performance. X-ray diffraction, transmission electron microscopy, ultraviolet–visible diffuse reflection spectroscopy, Fourier transform infrared spectroscopy, and photoluminescence spectroscopy confirmed the synthesized CdS/g-C3N4 ultrathin nanosheets. The photocurrent intensity and degradation of methyl orange (MO) of ultrathin CdS/g-C3N4 photocatalyst were 2 and 1.4 times higher than those of CdS/g-C3N4 nanocomposite obtained via ultrasound exfoliation without assistance of cadmium ion. These results were due to the well-matched band structure and close contact interfaces between the g-C3N4 nanosheets and CdS, which resulted in the effective transfer and separation of the photogenerated charge carriers. The mechanism for the photodegradation of MO by ultrathin CdS/g-C3N4 photocatalyst was also investigated.

Graphical abstractIt is easy to see from figure (a) that the much smaller CdS nanoparticles spread uniformly on the surface of g-C3N4 samples and form the composite structures of ultrathin nanosheets. It is proposed that the synergy effects of ultrasonic and ion promote the form of CdS/g-C3N4 heterojunctions. Based on the above results, a mechanism for the fabrication of ultrasonic CdS/g-C3N4 composites can be proposed and is illustrated in Scheme 1: the ultrasonic method provides a necessary drive for exfoliating C3N4, simultaneously, cadmium (acetate) is easy to dissolve or disperse in/on suitable solvents/supports and can decompose readily into Cd atom clusters under sonication conditions.Figure optionsDownload full-size imageDownload as PowerPoint slide