LAUSR

The fabrication of two-dimensional (2D) metal-organic frameworks (MOFs) and prussian blue analogues (PBAs) combines the advantages of 2D materials, MOFs and PBAs, resolving the poor electronic conductivity and slow diffusion in MOF materials for electrochemical applications. In this work, 2D leaflike zeolitic imidazolate framework (Co-ZIF and Fe-ZIF) as sacrifice template are in-situ converted into PBAs, realizing the successful fabrication of PBA/ZIF nano composites on nickel foam (NF), namely as CoCo-PBA/Co-ZIF/NF, FeFe-PBA/Fe-ZIF/NF, CoFe-PBA/Co-ZIF/NF, and Fe/CoCo-PBA/Co-ZIF/NF. Such fabrication can effectively reduce transfer resistance and greatly enhance electrons and mass transfer efficiency due to the electrochemical active PBA particles and NF substrate. These fabricated electrodes as multifunctional sensors achieve highly selective and sensitive glucose and H2O2 biosensing with very wide detective linear range, extremely low detection limit (LOD) and good stability. Among them, CoFe-PBA/Co-ZIF/NF exhibits the best sensing performance with a very wide linear range of 1.4 μM-1.5 mM, high sensitivity of 5270 μA mM-1 cm-2, low LOD of 0.02 μM (S/N = 3), remarkable stability and selectivity toward glucose. What is more, it can realize the excellent detection of glucose in human serums, demonstrating its practical application. Furthermore, this material as multi-functional electrochemical sensor also manifests superior detection performance against hydrogen peroxide with a wide linear range of 0.2-6.0 mM, high sensitivity of 196 μA mM-1 cm-2, and low detection limit of 1.08 nM (S/N = 3). The sensing mechanism for enhanced performance for glucose and H2O2 is discussed and proved by experiments in detail.