Two Novel Polyoxometalate-Encapsulated Two-Fold Interpenetrating <i>Dia</i> Metal-Organic Frameworks for the Detection, Discrimination And Degradation of Phenolic Pollutants

Phenols are widely used for commercial production, while they have posed a threat to the environment and human health. Thus, investigation of convenient and efficient methods for detection, discrimination and degradation of phenols becomes particularly important. Herein, two new polyoxometalate (POM)-based compounds [Co2(btap)4(H2O)4][SiW12O40] (Co-POM) and [Ni2 (btap)4(H2O)4][SiW12O40] (Ni-POM) (btap = 3,5-bis(triazol-1-yl)pyridine), are prepared via a hydrothermal synthesis method. The compounds show a fascinating structural feature of POM-encapsulated two-fold interpenetrating dia metal-organic framework. More importantly, beside the novel structures, the compound Co-POM realizes three in one, namely, simultaneous detection, discrimination and degradation of phenols. Specifically, the Co-POM shows an excellent colorimetric detection performance towards phenol with the detection limit (LOD) ca. 1.32 μ M, which is lower than most reported colorimetric detectors for phenol. Also, a new colorimetric sensor system based on Co-POM can discriminate phenol, 4-chlorophenol and o-cresol with ease. Further, the Co-POM exhibits a photocatalytic degradation property for 4-chlorophenol under irradiation of visible light with the highest degradation rate of 62 % after irradiation 5 h. Therefore, this work provides a first example of POMs-based multi-functional material for achieving the detection, discrimination and degradation of phenolic pollutants.