Potentiodynamic Bottom-Up Growth of Cu/MnO2 Composite Films as Glucose Sensing Electrode

Abstract

Copper/manganese dioxide (Cu/MnO₂) composite films were developed on indium doped tin oxide (ITO) coated glass substrates by layer-by-layer electrochemical deposition under potentiodynamic mode for glucose sensor application. Surface morphology of Cu/MnO₂ composite films together with pristine MnO₂ and Cu films as reference was examined by optical microscopy and atomic force microscopy. The Cu particle-like clusters are evenly covered on underlying MnO₂ forming a bi-layered structure. The present work mainly investigates the performance of composite Cu/MnO₂ electrode towards glucose detection using amperometric measurement. Electrochemical experiments showed that the Cu/MnO₂ exhibited higher catalytic capability for glucose oxidation than pristine MnO₂ and Cu indicating that composition of Cu with MnO₂ causes a synergistic effect for glucose oxidation on the electrode surface. The electroactive surface area for glucose sensing estimated from Randles-Seveik relation is larger for Cu/MnO₂ electrode. A linear correlation of oxidation peak current densities of Cu/MnO₂ electrode to glucose concentration (0.25 – 1.25 mM) indicated that the sensitivity is as high as 0.67 mA mM^-1 and detection limit is as low as 0.25 mM. The composite Cu/MnO₂ electrodes bear a promising potential for glucose sensor application.