Graphitic carbon nitride (g-C 3 N 4 ) as an efficient metal-free Fenton-like catalyst for degrading organic pollutants: the overlooked non-photocatalytic activity

• Published in: Water science and technology Vol. 81; no. 3; pp. 518 - 528
• Main Authors: Zhu, G X, Lu, T L, Han, L, Zhan, Y Z
• Format: Journal Article
• Language: English
• Published: England IWA Publishing 01.02.2020
• Subjects: Adsorption; Analytical methods; Carbon; Carbon nitride; Catalysts; Catalytic activity; Deactivation; Environmental Pollutants; Fourier transforms; Graphene; Graphite; Hydrogen Peroxide; Infrared spectroscopy; Metals; Nitriles; Nitrogen; Nitrogen Compounds; Oxidation; Performance evaluation; pH effects; Photocatalysis; Photoelectron spectroscopy; Photoelectrons; Pollutants; Pyrolysis; Quantum dots; Rhodamine; Scanning electron microscopy; Scavenging; Spectrum analysis; Stability; Synthesis; Urea; X ray photoelectron spectroscopy; X rays; X-ray diffraction; China
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/WST.2020.129

Graphitic carbon nitride (g-C N ) has attracted a large amount of research, mainly being used as a photocatalyst, but its Fenton-like catalytic performance has been overlooked. In this paper, the dark Fenton-like catalytic performance of g-C N was evaluated by degrading rhodamine B over a wide pH range. The results showed that the g-C N , which was synthesized by conventional urea pyrolysis without any modification, was an efficient metal-free heterogeneous Fenton-like catalyst. The highest activity occurred under a weakly alkaline condition of about pH 10. The experiment of catalyst recycling indicated that g-C N had long-term stability. The reactive oxidizing species of HO·, generated by the g-C N activating H O , was identified by EPR and further supported by a scavenging experiment of HO· using isopropanol as the scavenger. The HNO oxidation of g-C N resulted in catalytic deactivation, implying the catalytic activity originated from the surface reduced groups of g-C N . The structure of synthesized g-C N before and after the HNO oxidation was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy, and a possible catalytic mechanism was proposed.