Preparation of porous ZIF-67 network interconnected by MWCNTs and decorated with Ag nanoparticles for improved non-enzymatic electrochemical glucose sensing

Due to porous structure, larger specific area, and potential to functionalize further, metal–organic frameworks (MOFs) are gaining attention in various fields, including electrochemical sensing of various analytes. MOFs are known to have excellent electrochemical activity because they mainly constitute a rich metallic center, possess huge specific area, and have multiple valence states. However, electrocatalytic activities of MOFs are greatly reduced due to their poor electronic conductivity for which high conductivity species are incorporated into the MOFs. In the present work, Co-based MOF (ZIF-67) was used as a porous matrix to encapsulate silver nanoparticles (Ag NPs) and on the surface of ZIF-67 multi-walled carbon nanotubes (MWCNTs) were decorated to obtain Ag@ZIF-67/MWCNT nanocomposite for the non-enzymatic electrochemical detection of glucose. The surface morphology of the synthesized nanocomposite was investigated by scanning electron microscopy, while crystallographic characterization was performed by X-ray powder diffraction. Cyclic voltammetry and chronoamperometry techniques were used to for the electrochemical monitoring of glucose. The electrochemical results demonstrated that Ag@ZIF-67/MWCNT showed an improved catalytic activity towards glucose in the concentration range of 33 μM to 400 μM with a low detection limit of 0.49 μM (S/N = 3), and reaction sensitivity of 13.014 μA μM−1 cm−2 as well as good selectivity in presence of ascorbic acid and uric acid.