Improved NO2 Sensing Performance of Ternary Nanocomposites Based on Au-doped Co3O4/CuO

Abstract

To enhance the poor sensing capabilities of traditional p-type metal oxide semiconductor sensors, a novel gas sensor was designed with Co3O4/CuO heterostructure modified by glutathione (GSH)-reduced gold (Au), which was characterized by different analyses. The experiments showed that the 0.5[Formula: see text]wt.% Au–Co3O4/CuO gas sensor exhibited excellent sensing performance with a response value of up to 28.3 for 3[Formula: see text]ppm NO2 at a relatively low operating temperature ([Formula: see text]C). Besides, it demonstrated a linear relationship between detection concentration and response value, displayed good selectivity for NO2, showcased stability and exhibited repeatability. Moreover, the sensor revealed the ability to resist humidity at the optimal temperature. Finally, we proposed a gas sensing mechanism to explain the enhanced NO2 detection performance of the sensor, attributed to the heterojunction structure between Co3O4/CuO and the catalytic properties of Au. This led to an increase in adsorbed oxygen, as confirmed by XPS characterization. Therefore, the 0.5[Formula: see text]wt.% Au–Co3O4/CuO ternary nanocomposite gas sensor is deemed to be a highly effective sensing material that can be utilized to detect NO2 gas in real-life applications.