Potentiodynamic Bottom-Up Growth of Cu/MnO2 Composite Films as Glucose Sensing Electrode
Keywords:
Cu/MnO2 composite electrode, Potentiodynamic deposition, Glucose sensor; Sensitivity, Detection limitAbstract
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.