Ce incorporated pyrochlore Pr2Zr2O7 solid electrolytes for enhanced mild-temperature NO2 sensing.

NO 2 sensor has attracted extensive attention due to its important application in environment monitor. Conventional NO 2 sensors based on the yttria-stabilized zirconia (YSZ) electrolyte possess fast response, high sensitivity and good stability, whereas its ionic conductivity decreases significantly at low- and intermediate-temperature, limiting the practical application in motor vehicles. In this work, a pyrochlore-phase A 2 B 2 O 7 solid electrolyte, Pr 2 Zr 2−x Ce x O 7+δ (PZC), was applied for the first time to construct the amperometric-type NO 2 sensor. Ce incorporated significantly improved the sensing performance of the PZC NO 2 sensor with NiO as the sensing electrode. The effect of Ce-doped concentration and operating temperature on the sensitivity, selectivity, stability, response and recovery characteristics were investigated in detail. The results showed that the optimal sensor based on the Pr 2 Zr 1.9 Ce 0.1 O 7+δ substrate gave high sensitivity, excellent selectivity and quick response-recovery behavior to NO 2 gas. The gas-sensing mechanism was also discussed. The PZC sensors are well established effective for sensing NO 2 at mild-temperature working window of 500–700 °C, and thus exhibit the promising application in motor vehicles. [ABSTRACT FROM AUTHOR]