PURPOSE: To correctly detect the concentration of only a nitrogen oxide even when gas constituents such as hydrocarbon and carbon monoxide coexist by fitting electrodes to a gas detection section made of a specific composite oxide, and detecting the change of resistance due to the adsorption of the nitrogen oxide.
CONSTITUTION: Electrodes 2 made of a corrosion-resistant metal raw material are formed on the surface of a gas detection section 1 made of a thin plate- shaped bulk body containing 50wt.% of a composite oxide expressed by the formula Bi17Sr16Cu7Oz, they are connected to an ammeter with lead wires 3, and the change of resistance due to the adsorption of NOx is measured. For the content of the mixture other than Bi17Sr16Cu7Oz, the total of Sr14Cu24Oz, Bi2Sr3Cu2Oz, Bi4Sr8Cu5Oz, Bi2Sr3Oz, and BiSrOz must be below 50wt.%. Since this detection section l does not adsorb Hc, Co, the concentration of NOx can be correctly measured.
NOZAKI AYUMI
WAKATA MITSUNOBU
UCHIKAWA HIDEFUSA
