High temperature amperometric NO2 sensor based on nano-structured Gd0.2Sr0.8FeO3−δ prepared by impregnating method

•A amperometric NO2 sensor is proposed with Gd0.2Sr0.8FeO3−δ sensing-electrode.•The Gd0.2Sr0.8FeO3−δ nano-particles are prepared by impregnating method.•The sensor had good responses to NO2 at high temperature.

Aimed at automobile exhaust monitoring of NOx, a new-type amperometric sensor was fabricated by using yttria-stabilized zirconia (YSZ) as electrolyte and a nano-structured perovskite-type oxide Gd0.2Sr0.8FeO3−δ (GSF) as sensing-electrode (SE) prepared by impregnating method. The fabricated sensor was examined for detection of NO2 at high operating temperatures (500–800 °C) in N2 carrier gas. It was found that the response current of the sensor was almost linear to NO2 concentration from 25 to 500 ppm at 500–800 °C when SE was polarized at −400 mV. The sensitivity of the sensor reached 2.61 μA ppm−1 at 800 °C. The sensor showed good selectivity, response, reproducibility and stability to NO2.

Graphical abstractBased on an YSZ electrolyte and a nano-structured Gd0.2Sr0.8FeO3−δ sensing-electrode prepared by impregnating method, a new-type amperometric sensor is fabricated and tested. The fabricated sensor for detection of NO2 can be operated at high temperatures (500–800 °C). When the bias potential of −400 mV is applied to sensor the response currents of the sensor are almost linear to NO2 concentrations from 25 to 500 ppm at a fixed temperature. The sensor shows good sensitivity, response and stability to NO2. The sensitivity of the sensor reached up to 2.60 μA ppm−1 and the 90% response time is about 150 s for 500 ppm NO2 at 800 °C. Figure optionsDownload full-size imageDownload as PowerPoint slide