Harmonizing the cyano-group and Na to enhance selective photocatalytic O2 activation on carbon nitride for refractory pollutant degradation

Manipulating exciton dissociation and charge-carrier transfer processes to selectively generate free radicals of more robust photocatalytic oxidation capacity for mineralizing refractory pollutants remains challenging. Herein, we propose a strategy by simultaneously introducing the cyano-group and N...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2024-03, Vol.121 (12), p.1
Main Authors: Xu, Mingkai, Wang, Ruizhao, Fu, Haoyang, Shi, Yanbiao, Ling, Lan
Format: Article
Language:English
Subjects:
Additives
Antibiotics
Carbon
Carbon nitride
Carrier mobility
Charge density
Charge transfer
Current carriers
Electric fields
Excitons
Free radicals
Organic carbon
Oxidation
Pesticides
Photocatalysis
Photodegradation
Photooxidation
Physical Sciences
Plastic pollution
Pollutants
Robustness
Total organic carbon
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Summary:Manipulating exciton dissociation and charge-carrier transfer processes to selectively generate free radicals of more robust photocatalytic oxidation capacity for mineralizing refractory pollutants remains challenging. Herein, we propose a strategy by simultaneously introducing the cyano-group and Na into graphitic carbon nitride (CN) to obtain CN-Cy-Na, which makes the charge-carrier transfer pathways the dominant process and consequently achieves the selective generation of free radicals. Briefly, the cyano-group intensifies the local charge density of CN, offering a potential well to attract the hole of exciton, which accelerates the exciton dissociation. Meanwhile, the separated electron transfers efficiently under the robust built-in electric field induced by the cyano-group and Na, and eventually accumulates in the heptazine ring of CN for the following O2 reduction due to the reinforced electron sink effect caused by Na. As a result, CN-Cy-Na exhibits 4.42 mmol L−1 h−1 productivity with 97.6% selectivity for free radicals and achieves 82.1% total organic carbon removal efficiency in the tetracycline photodegradation within 6 h. Additionally, CN-Cy-Na also shows outstanding photodegradation efficiency of refractory pollutants, including antibiotics, pesticide plastic additives, and dyes. This work presents an innovative approach to manipulating the exciton effect and enhancing charge-carrier mobility within two-dimensional photocatalysts, opening an avenue for precise control of free radical generation.
ISSN:0027-8424
1091-6490
1091-6490
DOI:10.1073/pnas.2318787121