Two-phase modeling of a PEMFC with CO poisoning effect using dilute hydrogen feed

Abstract

A one-dimensional, two-phase mathematical model was developed to analyze the poisoning effect of anode CO kinetics on the performance of a PEM fuel cell. Both vapor and liquid water transport are examined inside the cell. The theoretical results indicate that a higher CO concentration results in large CO coverage across the anode catalyst layer. The slowing of the chemical reactions at both the anode and the cathode reduce the liquid water saturation level in the catalytic layers. At high CO concentration and dilute hydrogen feed, the effect of the electro-osmotic drag is small and less liquid water is generated at the cathode catalyst layer, causing the liquid water distribution to have a small slope across the membrane. The distribution of liquid water depends more strongly on the CO concentration than on dilution of hydrogen in the MEA of the fuel cell. A large dropping rate of the current density is observed in the range between 10-50 ppm CO. Increasing the amount of pure hydrogen drastically increases the current density for a wide range of CO contents, promoting the tolerance for CO of the fuel cell.