Comparison between Nafion and Polybenzimidazole (PBI) membranes for fuel cell type CO sensor

摘要

This study describes a new CO sensor based on a proton exchange membrane for combustion applications over 100 °C. One of the promising high-temperature polymers is based on the phosphoric acid doped polybenzimidazole (PBI) polymer. Output at less than 300 ppm CO was clearly detected with PBI at around 200 °C. Based on the polarization curves, the current density approximately linearly decreased with the decreasing voltage. It was found that PBI had a high CO to H_2 selectivity in the combustor exhaust. Sensor performance using PBI was less influenced by humidity than Nafion.