Platinum Nanoparticle Encapsulated Metal–Organic Frameworks for Colorimetric Measurement and Facile Removal of Mercury(II)

Pt nanoparticle (Pt NP)@UiO-66-NH2 composites were synthesized and encompassed the benefits of permanent porosity, high thermal and chemical stability of metal–organic frameworks (MOFs), together with the functional behavior of isolated Pt NPs. The PVP-stabilized Pt NPs with the average diameter of 2.48 nm were well dispersed and confined within the framework of UiO-66-NH2. Pt NPs possess highly peroxidase-like activities and make the composites oxidize 3,3′,5,5′-tetramethylbenzidine in the presence of H2O2. Moreover, the specific interaction between Hg2+ and Pt NPs leads to the effective suppression of the peroxidase-like activity of Pt NP@UiO-66-NH2, which endows excellent selectivity for Hg2+ measurement over the interfering metal ions. Based on the colorimetric sensing system, Hg2+ is linearly measured over the range from 0 to 10 nM with a detection limit of 0.35 nM. Moreover, the as-obtained Pt NP@UiO-66-NH2 nanocomposites exhibit high capacity and good selectivity for Hg2+ adsorption, which is succe...