title: Integrated oxygen-doping and dye sensitization of graphitic carbon nitride for enhanced visible light photodegradation.
abstract: Graphitic carbon nitride (GCN) is a promising metal-free photocatalyst while suffering from low charge mobility induced inefficient photocatalysis. In this work, oxygen doping was employed to enhance the photodegradation of organic pollutants in water on graphitic carbon nitride (GCNO) under visible light. For further absorption extension, four organic dyes (Eosin-Y, Perylene, Nile-red and Coumarin) were adopted to dye-sensitize the GCNO photocatalyst. It was found that O-doping can promote dye sensitization, which was dependent on the type of dyes and influenced the photodegradation efficiencies of methylene blue (MB) and phenol. Nile-red sensitized GCNO presented the best activity in MB degradation under λ>480nm irradiations while Eosin-Y showed the best sensitization performance for phenol degradation under λ>420nm light source. However, dye sensitization was not effective for enhanced pollutant degradation on GCN without O-doping. UV-vis diffuse reflectance spectra (UV-vis DRS), photoluminescence (PL) spectra, and photocurrent analyses were applied to investigate the mechanism of carriers' transfer, which indicated that dye molecules could inject extra electrons into GCNO energy band and the energy dislocation could suppress electron/hole recombination, enhancing photocatalytic performances.
authors.affiliation: Department of Chemical Engineering and CRC for Contamination Assessment and Remediation of the Environment (CRC CARE), Curtin University, GPO Box U1987, WA 6845, Australia.
authors.forename: Shizhen
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Chemical Engineering and CRC for Contamination Assessment and Remediation of the Environment (CRC CARE), Curtin University, GPO Box U1987, WA 6845, Australia; School of Engineering, Edith Cowan University, Joondalup, WA 6027, Australia.
authors.forename: Hongqi
authors.initials: H
authors.lastname: Sun
authors.affiliation: Department of Chemical Engineering and CRC for Contamination Assessment and Remediation of the Environment (CRC CARE), Curtin University, GPO Box U1987, WA 6845, Australia.
authors.forename: H M
authors.initials: HM
authors.lastname: Ang
authors.affiliation: Department of Chemical Engineering and CRC for Contamination Assessment and Remediation of the Environment (CRC CARE), Curtin University, GPO Box U1987, WA 6845, Australia.
authors.forename: Moses O
authors.initials: MO
authors.lastname: Tade
authors.affiliation: Department of Chemical Engineering and CRC for Contamination Assessment and Remediation of the Environment (CRC CARE), Curtin University, GPO Box U1987, WA 6845, Australia. Electronic address: Shaobin.wang@curtin.edu.au.
authors.forename: Shaobin
authors.initials: S
authors.lastname: Wang
keywords: Dye photosensitizing; Graphitic carbon nitride; Metal-free catalyst; Oxygen modification; Photodegradation