The effect of H 2S and CO mixtures on PEMFC performance

Abstract

Proton exchange membrane fuel cells (PEMFCs) most likely will use reformed fuel as the primary source for the anode feed which always contains carbon dioxide (CO) and hydrogen sulfide (H 2S). Trace amount of CO and H 2S can cause considerable cell performance losses. A comparison between the effect of CO and that of H 2S on PEMFC performance was made in this paper. Under the same conditions, the H 2S poisoning rate is much higher than CO because of different adsorption intensity. When the fuel stream contains the gas mixture (25 ppm CO and 25 ppm H 2S), the fuel cell performance deteriorates more quickly than 50 ppm CO but slowly than 50 ppm H 2S and can be only partially recovered by reintroducing neat H 2. The resulting effects of the mixtures can be divided into two parts roughly: during the inception phase, the cell voltage drops quickly and the actual values of anode overvoltage are bigger than the corresponding calculated values; then the deterioration rate of the cell performance decreases gradually.