AMPEROMETRIC SENSOR FOR CARBON-MONOXIDE BASED ON SOLID-STATE PROTONIC CONDUCTION

An amperometric three electrode sensor for CO operating at room temperature and using a solid state proton conductor as an electrolyte has been developed. The sensing electrode is made of platinum black, while the reference and counter electrodes consist of TiH(x) sheets. A thin film of zirconium phosphate is used as a proton conductor. The minimum CO concentration which can be detected is about 1 vpm, with a response time of about 20 s for 90% of the whole response, at 100% relative humidity. The response becomes lower with decreasing relative humidity and disappears at a relative humidity as low as about 50%. Ethanol interferes to a great extent, while methane is not appreciably detected.