Colorimetric/fluorescent/SERS triple-readout sensing of Mercury(Ⅱ) via in-situ growth of AgNPs in phenanthroline-functionalized covalent organic framework

• Published in: Sensors and actuators. B, Chemical Chemical, 2022-10, Vol.369, p.132361, Article 132361
• Main Authors: Xu, Yulong, Wu, Chengxin, Chu, Ning, Yang, Jiaxuan, Lin, Yanna, Chen, Xuwei
• Format: Article
• Language: English
• Subjects: AgNPs; Colorimetry; Covalent organic frameworks; Fluorescence; Functional groups; Mercury compounds; Mercury(Ⅱ); Nanocomposites; Nanoparticles; Pollutants; Pollution monitoring; SERS; Silver
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2022.132361

Targeted design of new covalent organic frameworks (COFs) with specific functions to build multi-readout platform for environmental pollutant monitoring has been gaining increasing interest. Herein, a fluorescent phenanthroline-functionalized COF (PA-COF) with favorable pore structure and reactive nitrogen-containing functional groups is designed and synthesized, and in-situ growth of silver nanoparticles (AgNPs) in PA-COF is achieved to produce PA-COF-based nanocomposite (PA-COF@AgNPs). Phenanthroline facilitates the anchoring of Ag+ in the skeleton of COF material via strong coordination interaction, and the confinement of in-situ grown AgNPs on PA-COF structure provides excellent dispersibility. The formed silver amalgam in the skeleton of PA-COF@AgNPs with the presence of Mercury(II) can oxidize colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue product (oxTMB) quickly, inducing obvious absorbance/SERS signal enhancement and fluorescence quenching of PA-COF@AgNPs. A colorimetric/fluorescence/SERS triple-readout strategy is thus developed for Hg2+ sensing with high sensitivity and excellent accuracy. The present study offers a promising strategy to develop a multi-readout assay platform for monitoring hazardous pollutants based on the targeted fabricating of novel COFs with specific functions. •PA-COF@AgNPs composite is fabricated via in-situ growth of AgNPs on COF skeleton.•PA-COF@AgNPs composite can be served as a high active SERS substrate.•A PA-COF@AgNPs based triple-readout strategy is developed for Hg2+ monitoring.•The multi-readout strategy exhibits high sensitivity and excellent accuracy.