Selective NO2 detection using YSZ-based amperometric sensor attached with NiFe2O4(+ Fe2O3) sensing electrode

A YSZ-based amperometric sensor using spinel oxide as a sensing electrode (SE) has been proposed here for detecting NO2 sensitively and selectively. Among the examined spinel-oxide SEs, NiFe2O4-SE was found to give relatively sensitive and selective response to NO2. Addition of 30 wt.% Fe2O3 into NiFe2O4-SE increased the NO2 response, while the responses to other interfering gases were maintained small. The sensor using NiFe2O4(+30 wt.% Fe2O3)-SE could detect NO2 as low as 5 ppm in humid air within 15 s (90% response time). The mechanism of NO2 selective behavior given by the sensor using NiFe2O4(+30 wt.% Fe2O3)-SE was investigated.