Sensor for measuring nitrogen oxide present in exhaust gas and flue gases

摘要

A nitrogen oxide sensor includes a solid electrolytic substrate (1) that exhibits oxide ion conductivity. A precious metal reference electrode (7) is only active w.r.t. oxygen and is shaped at one side section of the substrate. A measuring electrode (6) that is active w.r.t. nitrogen oxides (NOx) and oxygen (O2) is formed at the opposite side section of the substrate (1). The potential difference between the two electrodes indicates the NOx concentration. The nitrogen oxide in a gas to be tested is converted to N2O5 or NO3 for measurement at the measurement electrode.