Kinetics of Ethanol Oxidation on Electroless Ni ‐  P  / SnO2 / Ti Electrodes in  KOH  Solutions

Abstract

The electrolytic oxidation of ethanol was investigated on the electroless N i-P /SnQ/T i electrodes in IM KOH. The mechan isms of ethanol oxidation on the electrode were studied via cyclic vo l tammetry and polarization curves. The kinetic equations were derived, and the kinetic parameters were obtained f rom a compar i son of exper imental 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 ~ as well as k-l, are functions of applied potential. Ethanol oxidation on the electroless N i-P /SnQ/T i is through a chemical reaction with a rate constant kol. These rate constants were determined f rom the current-potential curves and the kinetic mode l at various concentrations of ethanol. The rate constants for electrochemical reaction could be expressed as kl (E) = 8.892 • l0 13 exp (0.6525FE/RT) s i, k_ ~ (E) = 8.034 x i0 6 exp (-0.3475FE/RT) s-I, where E was the applied potential vs. Ag/AgCl, and the chemical reaction rate constant (kcl) was 5.822 • i0 6 dm ~ mol- ~ s-~.