Two Polyoxometalate-Encapsulated Two-Fold Interpenetrating<b><i>dia</i></b>Metal–Organic Frameworks for the Detection, Discrimination, and Degradation of Phenolic Pollutants
Jianjiao Xin, Haijun Pang, Zhongxin Jin, Qiong Wu, Xiaojing Yu, Huiyuan Ma, Xinming Wang, Lichao Tan, Guixin Yang
Abstract
Phenols are widely used for commercial production, while they pose a hazard to the environment and human health. Thus, investigation of convenient and efficient methods for the 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 a POM-encapsulated twofold interpenetrating dia metal–organic framework. More importantly, besides the novel structures, the compound Co-POM realizes three functions, namely, the simultaneous detection, discrimination, and degradation of phenols. Specifically, Co-POM shows an excellent colorimetric detection performance toward phenol with a detection limit (LOD) ca. 1.32 μM, 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, Co-POM exhibits a photocatalytic degradation property for 4-chlorophenol under irradiation of visible light with the highest degradation rate at 62% after irradiation for 5 h. Therefore, this work provides the first example of a POMs-based multifunctional material for achieving the detection, discrimination, and degradation of phenolic pollutants.