High-response dual-purpose NO2 sensor with layered-Bi2WO6 sensing electrode

Abstract In this work, we successfully synthesized Bi2WO6 via hydrothermal method. Then, we fabricated a mixed-potential-type yttria-stabilized zirconia (YSZ)-based NO2 sensor, incorporating this material. Layered-Bi2WO6 exhibits excellent performance for NO2 detection at 550°C. We found that the working curve of the sensor is divided into two sections. Sensor sensitivities are 13.4 and 65.83 mV/decade in the range of 1–4 and 6–50 ppm NO2 concentration, respectively, indicating that the sensor has the prospect of a dual-purpose sensor to detect NO2 in air and automobile exhaust. The sensor also has good selectivity, stability, and repeatability. The layered structure of Bi2WO6, which significantly increases the three-phase boundary area and provides more active sites for the adsorption of NO2, plays a paramount role in enhancing the sensing performance. We discuss the associated sensing mechanism in detail.