Environment-friendly carbon quantum dots/ZnFe₂O₄ photocatalysts: Characterization, biocompatibility, and mechanisms for NO removal

Yu HUANG, Yan Ling LIANG, Yong Fang RAO, Dan Dan ZHU, Jun Ji CAO, Zhen Xing SHEN, Wing Kei HO, Shun Cheng Frank LEE

Research output: Contribution to journalArticles

133 Citations (Scopus)

Abstract

A highly efficient and environmentally-friendly oxidation process is always desirable for air purification. This study reported a novel carbon quantum dots (CQDs)/ ZnFe₂O₄ composite photocatalyst for the first time through a facile hydrothermal process. The CQDs/ ZnFe₂O₄ (15 vol %) composite demonstrates stronger transient photocurrent response, approximately 8 times higher than that of ZnFe₂O₄, indicating superior transfer efficiency of photogenerated electrons and separation efficiency of photogenerated electron–hole pairs. Compared with pristine ZnFe₂O₄ nanoparticles, CQDs/ ZnFe₂O₄ displayed enhanced photocatalytic activities on gaseous NOx removal and high selectivity for nitrate formation under visible light (λ > 420 nm) irradiation. Electron spin resonance analysis and a series of radical-trapping experiments showed that the reactive species contributing to NO elimination were ·O₂– and ·OH radicals. The possible mechanisms were proposed regarding how CQDs improve the photocatalytic performance of ZnFe₂O₄. The CQDs are believed to act as an electron reservoir and transporter as well as a powerful energy-transfer component during the photocatalysis processes over CQDs/ ZnFe₂O₄ samples. Furthermore, the toxicity assessment authenticated good biocompatibility and low cytotoxity of CQDs/ ZnFe₂O₄. The results of this study indicate that CQDs/ ZnFe₂O₄ is a promising photocatalyst for air purification. Copyright © 2017 American Chemical Society.
Original languageEnglish
Pages (from-to)2924-2933
JournalEnvironmental Science & Technology
Volume51
Issue number5
Early online dateFeb 2017
DOIs
Publication statusPublished - Mar 2017

Citation

Huang, Y., Liang, Y., Rao, Y., Zhu, D., Cao, J.-J., Shen, Z., et al. (2017). Environment-friendly carbon quantum dots/ZnFe₂O₄ photocatalysts: Characterization, biocompatibility, and mechanisms for NO removal. Environmental Science & Technology, 51(5), 2924-2933.

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