A fast phosphate colorimetric sensor based on MoS2/UiO-66 (Fe/Zr) nanocomposites as oxidase-/peroxidase-like nanoenzymes

The construction of sensing platforms based on nanoenzymes has been the focus of scientists from different countries. Since phosphate ion (Pi) is considered as an important indicator for water eutrophication, it is important to construct a fast, cost-effective, convenient and reliable determination method to monitor Pi for controlling water quality. In this study, MoS2 induced bimetallic–organic framework UiO-66(Fe/Zr) nanoparticles were prepared by a solvothermal method. Compared with that of pure UiO-66(Fe/Zr), MoS2/UiO-66(Fe/Zr) exhibits a higher peroxidase-like activity due to the generation of superoxide free radical (˙O2−). With the aid of the 3,3′,5,5′-tetramethylbenzidine (TMB) substrate together with H2O2, the enzyme-like behaviors of MoS2/UiO-66(Fe/Zr) as nanoperoxidase are evaluated. Interestingly, Zr4+ can specifically recognize Pi. Thus, according to the excellent peroxidase activity as well as specific recognition towards Pi of MoS2/UiO-66(Fe/Zr), a fast cost-effective colorimetric sensing platform has been established to determine phosphate in a good linear range of 10–100 μM with the limit of detection as low as 6.4 μM.