Effect of Electrochemical Surface Pretreatment on Electro-Catalytic Activity of Copper for Ethanol Oxidation in Alkaline Media

Resumo

The effect of different electrochemical surface treatments of a copper electrode was studied for electro-catalytic oxidation of ethanol in 1 M NaOH solution. Cyclic voltammetry and impedance spectroscopy techniques were used in this study. The surface morphology of treated electrodes was examined by scanning electron microscopy and atomic force microscopy. The results indicated that the electro-catalytic oxidation of ethanol can be strongly enhanced by electro-deposition of copper particles on the surface of an electrode and also by the anodically modified surface in NaCl solution. This enhanced electrode activity is related to an increase in the effective surface area and/or to an increase in the surface concentration of electro-active molecules or intermediates. In addition, the charge transfer resistance for ethanol oxidation reaction decreased as a result of surface treatments and the double layer capacitance increased due to an increase in surface porosity. Atomic force microscopy showed that surface roughness increased after pre-cycling polarization. The micrographs of the surface showed a micro porous structure.