Characteristic studies of a PBI/H3PO4 high temperature membrane PEMFC under simulated reformate gases

• A PBI/H3PO4 HT-PEMFC was experimentally studied under simulated reformate gases.
• CO decreases the performance due to an increase of the charge transfer resistance.
• Increasing the temperature improves the CO tolerance under reformate gases.
• The CO tolerance of a PBI/H3PO4 HT-PEMFC becomes weak in highly diluted H2.

A high temperature proton exchange membrane fuel cell is considered a solution to improve the cell performance under CO-contained hydrogen and to simplify the gas purification process of a reformate fuel cell system. In this study, polybenzimidazole-based phosphoric acid-doped fuel cells are studied under simulated reformate gases of different H2, N2 and CO concentrations. The experimental results show that the dilution effect of N2 has a minor impact on the cell performance in absence of CO. However, the CO poisoning increases the charge transfer resistance and leads to a substantial performance drop. This work also reveals that increasing the operating temperature can effectively improve the CO tolerance by suppressing the Pt–CO binding reaction. In addition, the CO poisoning effect becomes more significant in diluted H2. As a result, the CO concentration should be maintained lower than a critical level to prevent a high CO coverage on the catalyst which leads to a noteworthy voltage shut-down, especially in highly diluted H2.