Functionalized Mesoporous Photonic Crystal Film for Ultrasensitive Visual Detection and Effective Removal of Mercury (II) Ions in Water

Abstract Mercury ion (Hg 2+ ) contamination is a worldwide serious environment problem; exploring smart sensing and adsorption materials are urgently demanded for Hg 2+ monitoring and removal. Herein, a simple 1D photonic crystal to first ever feature capabilities of visually quantitative determination and effective adsorption toward Hg 2+ is facilely constructed by integrating a specifically designed thiourea‐functionalized nanocopolymer layer with a mesoporous TiO 2 layer. Based on strong chelation and porous structure, Hg 2+ is easily adsorbed on the copolymer and triggers vertically volumetric shrinkage, resulting in highlighted wavelength blue‐shifts and color changes in a broad Hg 2+ level scope. Utilizing the adsorption characteristic, Hg 2+ existing in aqueous media can be effectively removed by the photonic film with a remarkable uptake capacity of 739.6 mg g −1 . This portable nanolayered film exhibits full regeneration, facile recovery, desirable selectivity toward Hg 2+ , and shields interference from other metal ions, which enables future application for environmental determination and remediation. Furthermore, a novel nanopolymer‐based two‐regime Hg 2+ ‐capturing mechanism is first revealed by quartz crystal microbalance with dissipation monitoring, providing valuable references for future relevant adsorption researches.