Effect of Selected Airborne Contaminants on PEMFC Performance

Contaminants were selected from the Environmental Protection Agency lists. Six qualitative down selection criteria were used to reduce the list to the 21 1 st tier contaminants. The effect of 1 st tier contaminants, mostly organic with the exception of ozone, on PEMFC performance is reported. The behavior of these contaminants was classified into 5 different cases; no effect, recoverable effect, partly recoverable effect, irrecoverable effect and supra-recoverable effect. The steady state contamination and irrecoverable performance losses respectively varied from 0 to 90% and −2 to 80%. Contamination and recovery time scales significantly varied within a ∼0.01 to ∼28 h range. Acetaldehyde and propene were characterized by the new supra-recoverable effect. For trichlorofluoromethane, iso-propanol and propene, a decrease of the relative humidity led to a significant change in cell performance (steady states, time scales). This effect was ascribed to several causes including the scavenging effect of liquid water by contaminant dissolution and a non zero water reaction order. Two quantitative selection criteria based on observed fuel cell performance were used to reduce the 1 st tier list to 7 2 nd tier contaminants for more resource intensive tests. These 2 nd tier contaminants are acetonitrile, acetylene, bromomethane, iso-propanol, methyl methacrylate, naphthalene and propene.