Increasing the peroxidase-like activity of the MIL-100(Fe) nanozyme by encapsulating Keggin-type 12-phosphomolybdate and covering three-dimensional graphene.

To improve the peroxidase-like activities of metal-organic frameworks (MOFs) as nanozymes, a ternary MIL-100(Fe)@PMo@3DGO nanocomposite was designed and fabricated by encapsulating Keggin-type HPMoO (PMo) with fast and reversible multi-electron redox processes and an electron-rich structure into MIL-100(Fe), then being covered by three-dimensional graphene (3DGO) with higher conductivity, larger surface area, higher porosity, and better chemical stability. As a consequence, the as-prepared MIL-100(Fe)@PMo@3DGO nanocomposite exhibits excellent peroxidase-like activities, namely, the lowest limit of detection (0.14 μM) in the range of 1-100 μM for glucose to date, to the best of our knowledge, attributed to the individual and synergistic effects of HPMoO, 3DGO and MIL-100(Fe).