Reduction of CO Content in Hydrogen Rich Fuel by CO Electrolytic Oxidation for Reformed Gas Fueled PEFCs

Abstract

The possibility of the electrolytic oxidation of CO as a means of reducing the CO content in reformed gas for PEFCs was investigated. A two-cell stack of PEFCs was used as a CO electrolysis module. To study the CO adsorption rate and CO selectivity of the module, three types of electrolyzing methods, i.e., constant current electrolysis, potential stepped electrolysis, and repeating pulse electrolysis, were used. It was found that the CO concentration can be reduced from 1% to below the 50 ppm level when a voltage exceeding more than 0.4 V is applied to each cell of the module. The maximum selectivity of the CO electrolytic oxidation was observed to reach 18% using the repeating pulse electrolysis method in a low current region. However, in a high current region, the selectivity of the CO oxidation did not improve.