Boric acid functionalized FeO@CeO/Tb-MOF as a luminescent nanozyme for fluorescence detection and degradation of caffeic acid.

Caffeic acid (CA) is a natural polyphenol that can have various positive effects on human health. However, its extraction and processing can cause significant ecological issues. Therefore, it is crucial to detect and degrade CA effectively in the environment. In this study, we have developed a multifunctional magnetic luminescent nanozyme, FeO@CeO/Tb-MOF, which combines peroxidase activity to detect and degrade CA. The fluorescence of the nanozyme was significantly attenuated due to the specific nucleophilic reaction between its boronic acid moiety and the o-diphenol hydroxyl group of CA, energy competition absorption and photo-induced electron transfer (PET) effect. This nanozyme demonstrates a linear detection range from 50 nM to 500 μM and an exceptionally low detection limit of 18.9 nM, along with remarkable selectivity and stability. Moreover, the synergistic catalysis of FeO and CeO within FeO@CeO/Tb-MOF fosters peroxidase activity, leading to the generation of substantial free radicals catalyzed by HO, which ensures the efficient degradation of CA (∼95%). The superparamagnetic property of FeO further enables the efficient reuse and recycling of the nanozyme. This research provides a novel approach for the concurrent detection and remediation of environmental contaminants.