Abstract:

Ni-Mo alloy electrode, prepared by electrodeposition, were characterized for application to ethanol oxidation in 1 mol• L－ 1 KOH solution. Their electrochemical behavior was studied using cyclic voltammograms and quasi-steady-state current-potential curves. A mathematical model was developed to predict the behavior of ethanol oxidation on Ni-Mo alloy electrodes. The redox of Ni(OH)2/NiOOH couples in the alkaline solution is a preludial step for the ethanol electrooxidation, and the rate constants related to this reaction,k1 as well k－ 1,are functions of applied potential. Ethanol oxidation is carried out by a chemical reaction with rate constant kC1.The kinetic equations were derived and the kinetic parameters were obtained from a comparison of experimental results with kinetic equations. The rate constants of electrochemical reactions could be expressed as k1(E) =1.41× 107exp(0.5FE/RT)mmol• cm－ 2• s－ 1,k－ 1(E)=0.711 exp(0.5 FE/RT) mmol• cm－ 2• s－ 1,in which E was the applied potential vs SCE, and the chemical reaction rate constant, kC1,was 1.99× 10－ 4 cm• s－ 1.

Key words: Ni-Mo alloy, Ethanol oxidation, Kinetics, Mathematical model