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Improvement in durability of the planar CO sensor with a Nafion® laminate

1993; Elsevier BV; Volume: 354; Issue: 1-2 Linguagem: Inglês

10.1016/0022-0728(93)80322-9

1873-2569

Ayumu Yasuda, Noriyuki Yamaga, Kenji Doi, T Fujioka, Shigekazu Kusanagi,

Gas Sensing Nanomaterials and Sensors

Abstract A planar electrochemical CO sensor, using Nafion® as a solid H + conductor, was constructed. Long-term testing at 20°C and 60% relative humidity (RH) shows that the lifetime of the sensor without laminated Nafion® is less than one month. The deterioration is assumed to be related to the decrease in the CO oxidation reaction constant. However, the sensor with the Nafion® laminate, where the Nafion® is covered by a cast perfluorocycloether polymer film, shows stable CO sensitivity for three months. Although the lamination is found to prevent the decrease in both the CO permeation coefficient of the Nafion® film and the CO oxidation reaction constant on the electrode, the observed stability of the CO sensitivity is assumed to be due mainly to the stabilized CO oxidation reaction constant. Further long-term tests are under way, and so far a lifetime of more than two years has been obtained.