Temperature independent resistive oxygen sensor prepared using zirconia-doped ceria powders

A resistive oxygen sensor with extremely good temperature independence within a temperature range of 923–1123 K was fabricated from precipitated ceria–zirconia solid solution powders. Experimental results identified the as-precipitated powders as a nanocrystalline ZrO2-doped CeO2 (ZDC) solid solution phase. The amount of Ce3+ in CeO2 film was increased by doping with ZrO2, identified by XPS. The electrical resistance of ZDC film showed a more significant decreasing rate than that of the undoped CeO2 at lower oxygen partial pressure. An n-type semiconductance of ZDC films was obtained under oxygen partial pressures from 1.0 to <10−15 atm. We selected two compositions of the ZDC films whose activation energies were approximately equal (∼1.69 eV at 1.0 atm and ∼1.66 eV at 0.01 atm) for the fabrication of temperature independent resistive oxygen sensors. ZDC films containing 10 at% and 5 at% ZrO2 (10ZDC and 5ZDC) were used as OMM (oxygen partial pressure measurement material) and TCM (temperature compensating material), respectively. This study confirms the conductive behaviors of ZDC at various oxygen partial pressures as a function of temperature, as well as the suitability of ZDC films for application as temperature independent oxygen sensors. The dynamic response of the resistive oxygen sensor with TCM also revealed that the sensor possessed a relatively good sensibility and stability.