Enzyme-free glucose sensor based on layer-by-layer electrodeposition of multilayer films of multi-walled carbon nanotubes and Cu-based metal framework modified glassy carbon electrode

A high-performance nonenzymatic glucose sensor was successfully prepared by a layer by layer strategy through electrodeposition assembling multilayer films of Cu-metal-organic frameworks/multi-walled carbon nanotubes (Cu-MOF/MWNTs) modified glassy carbon electrodes (GCE). Different multilayer films of Cu-MOF/MWNTs modified GCE (Cu-MOF/MWNTs/GCE) were prepared by repeating the electrodeposition of MWNTs onto the GCE in an MWNTs solution (MWNTs/GCE) and electrodeposition of the Cu-MOF layer onto the MWNTs film surface to form a Cu-MOF/MWNTs composite layer in the crystallization solution of Cu-MOF. Results confirmed that this method to fabricate multilayer composite films on the GCE was fast and convenient, and that multilayer composite films were stable and unified. The electrode modified by the multilayer composite films could effectively increase the exposure of active sites and increase the surface area of reactive contact. The GCE modified by eight layers (four multilayers Cu-MOF/MWNTs films) showed the optimum catalytic performance in the oxidation of glucose. The novel glucose sensor exhibited a wider detection linear range of 0.5 μM-11.84 mM, with a detection limit of 0.4 μM and a sensitivity of 3878 μA cm^-2 mM^-1. Moreover, the electrochemical response of the sensor on glucose was fast (within 0.3 s) and stable, exhibited good selectivity and was free of interference.