Development of WO3 thick-film NO sensors and their application in monitoring of steam power plant exhausts

Sensors for the determination of NO levels in steam power plants emissions have been fabricated as low cost, screen printed, metal oxide film devices. WO3(Bi2O3) thick films have been used as gas sensitive elements in the sensors. It is necessary that the sensor operating temperature has to be 300 °C, because the ambient temperature varies between 250 °C and 290 °C in boiler shunt tubes where the gas sensors are usually set in. The characteristics of the sensors have been investigated at 300 °C. The results of the investigations are discussed.