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.

It 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 as PowerPoint slide