Patent ID: 7763154

Claim:
A sensor element for determining the concentration of a target gas in a gas mixture, comprising: at least one first auxiliary electrode in direct contact with the gas mixture; at least one second auxiliary electrode in direct contact with the gas mixture, the at least one second auxiliary electrode configured to at least partially remove nitrogen oxide contained in the gas mixture, the second auxiliary electrode having a first surface region containing a platinum-precious metal alloy and a separate second surface region containing platinum, the second surface region being catalytically more active than the first surface region and disposed downstream from the first surface region with respect to a flow of the gas mixture, so that the gas mixture contacts the first region before contacting the second region; and a measuring electrode in direct contact with the gas mixture, the measuring electrode arranged to measure the gas mixture after the gas mixture has diffused downstream from the at least one second auxiliary electrode; wherein the at least one first auxiliary electrode is at least temporarily connected to a potential such that at least one of hydrogen, carbon monoxide and nitrogen oxide contained in the gas mixture is at least partially removed from the sensor element, and wherein a signal generated using the measuring electrode is used to determine the concentration of the target gas.