Electrokinetic and impedimetric dynamics of FeCo-nanoparticles on glassy carbon electrode

Abstract

The electrochemical dynamics of a film of FeCo nanoparticles were studied on a glassy carbon electrode (GCE). The film was found to be electroactive in 1 M LiClO4 containing 1:1 v/v ethylene carbonate – dimethyl carbonate electrolyte system. Cyclic voltammetric experiments revealed a diffusion-controlled electron transfer process on the GCE/FeCo electrode surface. Further interrogation on the electrochemical properties of the FeCo nanoelectrode in an oxygen saturated 1 M LiClO4 containing 1:1 v/v ethylene-carbonate-dimethyl carbonate revealed that the nanoelectrode showed good response towards the electro-catalytic reduction of molecular oxygen with a Tafel slope of about 120 mV which is close to the theoretical 118 mV for a single electron transfer process in the rate limiting step; and a transfer Coefficient (α) of 0.49. The heterogeneous rate constant of electron transfer (ket), exchange current density (io) and time constant (τ) were calculated from data obtained from electrochemical impedance spectroscopy and found to have values of 2.3 x 10-5 cm s-1, 1.6 x 10-4 A cm-2 and 2.4 x 10-4 s rad-1, respectively.