“Two‐in‐One” Europium Ions Functionalized Nitrogen‐Rich COF for High Selective, Sensitive Detection, and Solar‐Driven Photo‐Elimination of Tetracycline

ABSTRACT Excessive use of tetracycline (TC) has led to increasing residues in water and agricultural products, which induce threats to human health and ecological environment. Therefore, it is important to develop materials capable of simultaneously monitoring and eliminating TC. Herein, a nitrogen‐rich covalent organic framework (TAPP‐TNBTA‐COF) with anchoring Eu 3+ ions (TAPP‐TNBTA‐COF@Eu) is delicately designed and synthesized for the first time, for trace detection and then photo‐elimination of TC. The unique structure of TAPP‐TNBTA‐COF provides numerous binding sites for Eu 3+ ions. Eu 3+ ions act as the recognition sites and emit specific fluorescence response signal to TC via “antenna effect”. Thus, TAPP‐TNBTA‐COF@Eu as a “turn‐on” fluorescence sensor exhibits outstanding selectivity and sensitivity, rapid response and non‐interference toward TC. Notably, the detection limit of TC by TAPP‐TNBTA‐COF@Eu reaches as low as 0.061 nM, with a wide detection range from 0 to 100 µM. Subsequently, TAPP‐TNBTA‐COF@Eu, leveraging its porphyrin units, achieves photocatalytic oxidation to degrade TC, with a degradation rate of 83% within 60 min, as well as good reusability. The mechanisms of detection and photocatalysis by TAPP‐TNBTA‐COF@Eu are discussed in detail. This work not only displays fascinating performances of the nitrogen‐rich heterocyclic COF but also offers tailored COFs architectures strategy for targeting multifunctional applications.