Facile preparation of a highly sensitive nonenzymatic glucose sensor based on multi-walled carbon nanotubes decorated with electrodeposited metals

Abstract

Novel multi-walled carbon nanotubes decorated with nickel, copper, and silver (Ni/CuAg/MWCNT) have been successfully fabricated for a nonenzymatic glucose sensor by the electrocodeposition of copper and silver and sequential electrodeposition of nickel using a MWCNT-modified electrode. The Ni, Cu, and Ag species deposited on MWCNT were indicated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Tests with various scan rates and pH conditions indicate that a diffusion-controlled in the electrochemical system and the hybrid composite is stable. In alkaline condition, the electrode shows good activity towards glucose oxidation with low overpotential with obvious oxidation peaks at +0.38 V and +0.5 V and a current response that is 1.7–5.8 times greater than those obtained using Ni/CuAg and MWCNT modified electrodes. Amperometry (E_app. = +0.6 V) indicates a response time of 10 s; one linear range of 5 × 10⁻⁶–4.05 × 10⁻⁴ M, with high sensitivity of 5007 μA mM⁻¹ cm⁻² and a low detection limit of 5 × 10⁻⁶ M (S/N = 3). It can effectively analyse glucose concentration avoiding interference. The modified electrode can be a nonenzymatic glucose sensor due to its low overpotential, high sensitivity, good selectivity, good stability, and low cost.