Precise Engineering of Fluorescent Covalent Organic Frameworks Nanoenzymes for Synergistic Enhancement of Monitoring and Photocatalytic Degradation of Mesotrione

ABSTRACT The residue of mesotrione poses an increasingly serious threat to the environment and human health. Thus, it is essential to establish a platform that integrates rapid detection and efficient degradation. Covalent organic frameworks (COFs) materials have garnered significant attention owing to their designability. However, achieving multifunctional integration by synergistically optimizing their luminescence and catalytic performance through structural regulation remains a challenge. In this study, Py‐DA‐COF and Py‐TD‐COF were synthesized through rational design. Spectroscopic analysis and theoretical calculations suggest that the enhanced conjugation of donor–acceptor (D–A) characteristics in Py‐TD‐COF increases the oscillator strength, which is the intrinsic mechanism for its remarkable fluorescence enhancement. Based on this, Py‐TD‐COF has been employed as a decidedly selective fluorescent probe for mesotrione. To further enhance the performance, Py‐TD‐COF@Cu composite materials were constructed. This material demonstrates excellent peroxidase‐like mimetic activity. Based on this, a novel colorimetric detection method based on catalytic signal amplification has been established. Additionally, this study explored the application of Py‐TD‐COF in pollutant treatment by fabricating it into a self‐supporting film, which demonstrated excellent photocatalytic degradation ability for pesticides under simulated sunlight. Py‐TD‐COF can achieve complete degradation of mesotrione within 60 min. In situ infrared spectroscopy further confirmed the changes during the detection and degradation processes. In summary, this work not only clarifies the distinct structure–activity relationship of COF fluorescence enhancement but also realizes a closed‐loop solution from dual‐mode (fluorescence/colorimetric) high‐sensitivity monitoring to photocatalytic degradation on the same material platform, offering new perspectives for the design of multifunctional intelligent materials for practical environmental governance.