Origin of the enhanced photocatalytic activity of graphitic carbon nitride nanocomposites and the effects of water constituents

Autor: Jie-An Li, Ting-Wei Lee, Chang-Ru Zhong, Chiaying Chen, Yu-Heng Lai, Tae-Jun Ha
Rok vydání: 2020
Předmět:
Zdroj: Carbon. 167:852-862
ISSN: 0008-6223
DOI: 10.1016/j.carbon.2020.06.028
Popis: A metal-free heterostructure system composed of graphitic carbon nitride (g-C3N4), reduced graphene oxide (rGO), and cyclooctasulfur (α-S) is developed as a facile route for establishing efficient photocatalysts. We aim to identify the governing factors that contributed to the photochemical performance of g-C3N4/rGO/α-S nanocomposites, which are important to advance potential applications but remain unexplored. The results indicate that the constituent ratio of each component in g-C3N4/rGO/α-S composites leads to varying surface microstructure, band alignment, and photochemical properties. The enhanced visible-light photocatalytic activity originates from an upward shift of the conduction bands toward higher energies, higher content of sp2-hybridized pyridine nitrogen in triazine rings (C N–C), and a lower amount of hydrogen bonds. The established structural integration informs a guiding framework for the design of emerging g–C3N4–based nanocomposites. Additionally, the influence of humic acid (HA) on photocatalytic decontamination was studied and shows an overall detrimental effect on the photocatalytic activity of g-C3N4 nanocomposites. Although HA advanced the photoexcited electrons, and therefore the reactive oxygen species, as well as enhanced the adsorption of the pollutants onto g-C3N4, especially at lower pH, attenuation of oxygen transfer as a result of active site competition between oxygen and target pollutants was found.
Databáze: OpenAIRE
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