Quantitatively regulating the ketone structure of triazine-based covalent organic frameworks for efficient visible-light photocatalytic degradation of organic pollutants: Tunable performance and mechanisms

As promising visible-light-responsive photocatalysts, triazine-based covalent organic frameworks (CTFs) still suffer from broad bandgap and high electron-hole recombination. As such, different contents of electron-rich ketone group were introduced to CTFs (X % keto-CTF), aiming to clarify the mechanism of quantitatively regulating ketone for enhanced visible-light photocatalytic performance of CTFs. As ketone content increased, the bandgap narrowed, electron-hole recombination decreased, charge transfer and quantum yield increased. As a result, keto-CTF outperformed other keto-CTFs in visible-light photocatalytic degradation of tetracycline, and apparent rate constant of TC (kobs) was 3.69 times higher than that of CTF. Importantly, ketone tuning induced varied types and concentrations of reactive species. Integrated with quantitative structure-activity relationships (QSARs) analysis and density functional theory (DFT) calculations, this study unravels how ketone content regulates bandgap structure of CTF, affects the contribution of varied reactive species, and quantitatively en-hances the photocatalytic performance of CTFs. It also provides novel insights into the precise design and syn -thesis of CTFs-based catalyst structures for high-efficient visible-light photocatalytic degradation of organic pollutants.

Automated summary

This study investigates the enhanced visible-light photocatalytic performance of triazine-based covalent organic frameworks (CTFs) by tuning the ketone content. The introduction of electron-rich ketone groups narrows the bandgap, reduces electron-hole recombination, and increases charge transfer and quantum yield. The keto-CTF outperforms other keto-CTFs in the degradation of tetracycline, with a 3.69 times higher apparent rate constant. Furthermore, the study sheds light on how ketone content regulates the bandgap structure, affects reactive species, and quantitatively enhances the photocatalytic performance of CTFs, providing valuable insights into the design and synthesis of CTFs-based catalyst structures for efficient visible-light photocatalytic degradation of organic pollutants.