Kinetic study of CO desorption from cathodic electrochemically treated carbon paper supported Pt electrodes

Platinum particles were grown directly by an electrodeposition process on electrochemically treated carbon paper (CP) for kinetic study of carbon monoxide (CO) desorption. The treatment on CP was performed by applying −2 V for cathodic oxidation over 5 min. Treated CP was characterized by FTIR to investigate the oxygen groups on its surface. CO surface coverage at each temperature was determined by monitoring changes in Had (adsorbed hydrogen) desorption charge during CO stripping at different desorption times (300 to 1800 s). CO coverage of the cathodic electrode is lower than non-treated one in all temperatures. Desorption rate constants were calculated for cathodic and non-treated electrodes. From 25 to 85 °C, rate constants for cathodic electrode are higher than the non-treated electrode at all temperatures. The activation energies for desorption, estimated from data obtained by the experiments, are 28480 and 18900 J.mol-1 for non-treated and cathodic electrode, respectively. This shows that CO desorption is easier on the surface of the cathodic electrode than non-treated electrode due to the presence of oxygen surface groups. 

Keywords:

Cathodic treatment , carbon paper , CO Poisoning , Kinetics Desorption , PEM fuel cell