Response Properties of Amperometric CO Sensor Using a Polybenzimidazole (PBI) Membrane above 140°C

A new amperometric sensor based on proton conducting membranes to CO was investigated. It was observed that the sensor current density showed almost linearity against CO concentration in the range of 0–3000 ppm at 200°C. In addition, the sensitivity at less than 300 ppm CO was detected clearly using phosphoric acid doped polybenzimidazole (PBI) membrane. It was found that PBI membrane had high selectivity of CO to H2 in combustor exhaust gases at 200°C. Sensor performance using PBI membrane was less influenced by humidity than Nafion.