Electrochemical and ESR study of the mechanism of oxidation of phenazine-di-N-oxide in the presence of cyclohexanol on glassy carbon and single-walled carbon nanotube electrodes

Abstract

The mechanism of oxidation of phenazine-di-N-oxide in the presence of cyclohexanol was studied by cyclic voltammetry on glassy carbon (GC) and single-walled carbon nanotube (SWCNT) electrodes in 0.1 M LiClO4 solutions in acetonitrile. The effect of cyclohexanol on the shape of the cyclic voltammograms of phenazine-di-N-oxide and the intensity of the ESR signal of its radical cation was investigated. It was shown by ESR that the products of the one-electron oxidation and reduction of phenazine-di-N-oxide were radical cations and anions. The catalytic currents were recorded during the oxidation of phenazine-di-N-oxide on the SWCNT and GC electrodes in the presence of cyclohexanol. The results were explained in terms of the E1C1E2C2 mechanism of the two-stage electrode process characterized by the catalytic current recorded at the second electrode stage. The overall two-electron catalytic oxidation of cyclohexanol in the complex with the phenazine-di-N-oxide radical cation was assumed to occur. It was shown that SWCNT electrodes can be used in the electrocatalytic oxidation of organic compounds in the presence of the electrochemically generated phenazine-di-N-oxide radical cation.