Electrochemical kinetic investigation of NADH oxidation on Prussian blue-mediated chemically reduced graphene oxide nanosheets

The oxidation of reduced nicotinamide adenine dinucleotide (NADH) has been investigated on a Prussian blue (PB)-mediated reduced graphene oxide (rGO)-modified glassy carbon electrode (GCE) through various electrochemical techniques. Graphene oxide (GO), initially prepared by a modified Hummer's method, was subsequently reduced to rGO, and the materials were characterized by means of transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. Preliminary electrochemical studies were performed by cyclic voltammetry (CV), which showed that PB-rGO/GCE exhibited the highest electrocatalytic activity. Electrokinetic parameters, such as number of electrons and rate constant, have been evaluated by hydrodynamic voltammetry. Furthermore, electrochemical impedance spectroscopy (EIS) has been carried out at various oxidation potentials in the frequency region between 0.1 Hz and 106 Hz. A decrease in double-layer capacitance was observed, which validated the adsorption characteristics of the electrode. Finally, the detection of NADH on PB-rGO/GCE was performed by differential pulse voltammetry (DPV), which gave two linear ranges: 100 mu M-1200 mu M and 1400 mu M-2800 mu M, with a detection limit of 68.35 mu M.