Enhanced chlorine sensing performance of the sensor based NAISCON and Cr-series spinel-type oxide electrode with aging treatment

Abstract NASICON-based gas sensors attached with Cr-based spinel-type oxide (ACr 2 O 4 , A = Zn, Co, Ni) sensing electrode were fabricated, and their gas sensing properties were tested for response to chlorine (Cl 2 ). In comparison with other spinel-type oxides, CoCr 2 O 4 -based sensor showed the maximum response to Cl 2 at 300 °C, giving a response of −226 mV to 1 ppm of Cl 2 , which was about 3.3 and 1.3 times higher than that sensors-based on ZnCr 2 O 4 and NiCr 2 O 4 , respectively. Moreover, the sensor exhibited excellent selectivity toward Cl 2 against the other interference gases, such as CO, NO, NO 2 , H 2 , C 7 H 8 , NH 3 and CH 4 . Interestingly, the performance of sensor could be markedly improved after aging at 300 °C for 60 days. Combined with the analysis by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and BET, a possible mechanism for the influence of aging on the Cl 2 -sensing properties of sensor was proposed.