Decoration of Carbon Nanotube Films with Iridium Nanoparticles and Their Electrochemical Characterization

Abstract

We report the development of a novel nonenzymatic glucose sensor based on single-walled carbon nanotube film electrodes coated with iridium nano-particles (IrNPs-SWCNT). The SWCNT film electrode was first loaded with iridium nanoparticles (IrNPs) by an easily controllable chronocoulometry technique. The SWCNT film electrode coated with IrNPs was characterized by field emission scanning electron microscopy and electrochemical techniques like cyclic voltammetry (CV) and amperometry. There was no current response for glucose oxidation in neutral and acidic media, but a couple of oxidative and reductive peaks were observed when the IrNPs-SWCNT electrode was scanned in alkaline media, showing the strong electrocatalytic activity toward glucose oxidation. Amperometric measurements showed a high sensitivity of 63 mu Acm(-2) mM(-1) and a detection limit of 17 mu M; further, the measurements showed a linear range of 0.59-14 mM. To improve the selectivity of the electrode, the prepared IrNPs-SWCNT film electrode was coated using a 1.0% Nafion aqueous solution. When the electrodes were exposed to interfering substances such as uric acid and ascorbic acid, there were no significant signals observed from these substances, indicating that Nafion is an effective permselective polymer barrier. The sensitivity of the Nafion-coated electrode was 23 mu Acm(-2) mM(-1) and the detection limit was 47 mu M. In addition, the electro-catalytic activity of the Nafion-coated electrode was still stable after 50 cycles in the presence of a 3.0 mM glucose solution. as measured by CV.