Oxygen sensor

摘要

An oxygen sensor includes a hollow tubular element made of a solid electrolyte capable of conducting oxygen ions. The inner surface of the element is exposed to the atmosphere, and the outer surface thereof is exposed to an exhaust gas of which the oxygen concentration is to be detected. First and second electrodes are arranged on the inner and outer surfaces of the element, respectively. The second electrode is provided with a coating which contains a catalyst for causing and promoting a water gas reaction of carbon monoxide contained in the exhaust gas approaching the second electrode. Alternatively, a large number of pellets containing the catalyst are charged in the space between the tubular element and a protective tube surrounding the element.