Application of Ti/RuO2-Ta2O5 electrodes in the electrooxidation of ethanol and derivants:: Reactivity versus electrocatalytic efficiency

The influence of the preparation method on the performance of RuO2-Ta2O5 electrodes was evaluated toward the ethanol oxidation reaction (EOR). Freshly prepared RuO2-Ta2O5 thin films containing between 30 and 80 at.% Ru were prepared by two different methods: the modified Pechini-Adams method (DPP) and standard thermal decomposition (STD). Electrochemical investigation of the electrode containing RuO2-Ta2O5 thin films was conducted as a function of electrode composition in a 0.5-mol dm(-3) H2SO4 solution, in the presence and absence of ethanol and its derivants (acetaldehyde and acetic acid). At a low ethanol concentration (5 mmol dm(-3)), ethanol oxidation leads to high yields of acetic acid and CO2. On the other hand, an increase in ethanol concentration (15-1000 mmol dm(-3)) favors acetaldehyde formation, so acetic acid and CO2 production is hindered, in this case. Electrodes prepared by DPP provide higher current efficiency than STD electrodes for all the investigated ethanol concentrations. This may be explained by the increase in electrode area obtained with the DPP preparation method compared with STD. (c) 2008 Elsevier Ltd. All rights reserved.