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

• 成果类型: Article
• 署名作者: Xu, Mingkai; Wang, Ruizhao; Fu, Haoyang; Shi, Yanbiao; Ling, Lan
• 署名单位: Tongji University; Shanghai Jiao Tong University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-10048
• DOI: 10.1073/pnas.2318787121
• 发表日期: 2024-03-19
• 关键词: exciton dissociation; g-c3n4; interfaces; oxidation; defects

摘要

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 simultane-ously 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 O-2 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 photodegra-dation 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.