Electrooxidation of carbon monoxide and formic acid on polycrystalline palladium
Date
2012-05-01
Authors
Sacci, Robert Lee
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Abstract
A systematic study of formic acid electrooxidation on polycrystalline palladium is presented. The study begins with a discussion on the oxide growth process on platinum and palladium. CO electrooxidation under controlled mass transport is studied in order to elucidate the manner in which Pd interacts with CO, a proposed poisoning species in formic acid oxidation. The mechanism of formic acid oxidation is studied using various potentiodynamic techniques, including dynamic electrochemical impedance spectroscopy, which provides impedance measurements during a voltammogram. Through kinetic analysis, a model for the oxidation was developed. The impedance measurements support both the dc measurements as well as the results of the oxidation model. It was determined that CO formation was slow on Pd within the time scale of the experiments. The chief cause of surface deactivate was then determined to be the Pd surface interaction with the (bi)sulfate adsorption in the double layer region.
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Keywords
Carbon monoxide, formic acid, fuel cells, impedance, Electrochemistry, Oxidation, Kinetics