KINETICS OF ETHANOL OXIDATION ON ELECTROLESS NI-P/SNO2/TI ELECTRODES IN KOH SOLUTIONS

The electrolytic oxidation of ethanol was investigated on the electroless Ni-P/SnO2/Ti electrodes in 1M KOH. The mechanisms of ethanol oxidation on the electrode were studied via cyclic voltammetry and polarization curves. The kinetic equations were derived, and the kinetic parameters were obtained from a comparison of experimental results and the kinetic equations. The redox reaction of the nickel electrode in the alkaline solution is reversible, and the rate constants related to this reaction, k(1) as well as k(-1), are functions of applied potential. Ethanol oxidation on the electroless Ni-P/SnO2/Ti is through a chemical reaction with a rate constant k(c1). These rate constants were determined from the current-potential curves and the kinetic model at various concentrations of ethanol. The rate constants for electrochemical reaction could be expressed as k(1) (E) = 8.892 x 10(-13) exp (0.6525FE/RT) s(-1), k(-1) (E) = 8.034 x 10(-6) exp (-0.3475FE/RT) s(-1), where E was the applied potential vs. Ag/AgCl, and the chemical reaction rate constant (k(cl)) was 5.822 x 10(-6) dm(3) mol(-1) s(-1).