Gasmessfühler und Herstellungsverfahren dafür

摘要

PROBLEM TO BE SOLVED: To provide a gas sensor element for accurately detecting the concentration of specific gas components such as NOx by reducing oxygen ion current due to reduction/decomposition of Rh2O3.

SOLUTION: This gas sensor element 1 is characterized in that it is provided with an oxygen pump cell 2 for adjusting oxygen concentration in an internal space 7 into which a measured gas is brought and a sensor cell 4 for detecting NOx concentration in the measured gas, and that an electrode 4a facing to the internal space 7 of the sensor cell 4 is a Rh-containing cermet electrode. The sensor element 1 is made such that the pump cell 2 and the sensor cell 4 are layered and baked, and then previous treatment is performed by passing a current through the sensor 4. Rh2O3produced in the electrode 4a facing to the internal space 7 of the sensor cell 4 in the baking process is reduced to metallic Rh. Only oxygen ion current due to the reduction/decomposition of NOx can be accurately detected since oxygen ion current due to the reduction/decomposition of Rh2O3is not added thereto when detecting the NOx concentration.

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