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

Abstract

Metal-organic frameworks (MOFs) are a class of supramolecular solid material composed of metal cations and organic linkers in a hybrid network. Due to porous structure, larger specific area, and potential to functionalize further, MOFs are gaining attention in different fields such as in gas storage, drug delivery gas and sensing., including electrochemical sensing of various analytes. MOFs are known to have excellent electrochemical activity because they are mainly constituted of 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) is used as a porous matrix for encapsulation of Ag-NPs and MWCNTs were decorated on the ZIF-67 surface to obtain Ag@ZIF-67/MWCNT nanocomposite for the non-enzymatic electrochemical detection of the glucose. Scanning electron microscopy was used for the surface morphology of the synthesized nanocomposite. while crystallographic characterization was done by using X-Ray powder diffraction characterization technique. 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 including 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.