Plasma-exfoliated g-C₃N₄ with oxygen doping: tailoring photocatalytic properties

Abstract

Heteroatom doping and defect engineering have been proposed as effective ways to modulate the energy band structure and improve the photocatalytic activity of g-C₃N₄. In this work, ultrathin defective g-C₃N₄ was successfully prepared using cold plasma. Plasma exfoliation reduces the thickness of g-C₃N₄ from 10 nm to 3 nm, while simultaneously introducing a large number of nitrogen defects and oxygen atoms into g-C₃N₄. The amount of doped O was regulated by varying the time and power of the plasma treatment. Due to N vacancies, O atoms formed strong bonds with C atoms, resulting in O doping in g-C₃N₄. The mechanism of plasma treatment involves oxygen etching and gas expansion. Photocatalytic experiments demonstrated that appropriate amount of O doping improved the photocatalytic degradation of rhodamine B compared with pure g-C₃N₄. The introduction of O optimized the energy band structure and photoelectric properties of g-C₃N₄. Active species trapping experiments revealed ·O₂^– as the main active species during the degradation.

Graphical abstract

Keywords

graphitic carbon nitride / cold plasma / oxygen doping / nitrogen defect / visible-light photocatalysis

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Competing interests

The authors declare that they have no competing interests.

Acknowledgements

This work was supported by National Natural Science Foundation of China (Grant No. 22278316).

Electronic Supplementary Material

Supplementary material is available in the online version of this article at https://doi.org/10.1007/s11705-023-2381-1 and is accessible for authorized users.

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