ZnO/PANI nanoflake arrays sensor for ultra‐low concentration and rapid detection of NO 2 at room temperature

With the development of environmental monitoring, it is urgent to establish NO 2 sensor with good sensing performance. Compared with the traditional NO 2 sensors made of metal oxides, NO 2 sensors made of n‐p heterostructure nanocomposites have good sensing performance in detection limit and operating temperature. ZnO nanoflake arrays with polyaniline film grown on the surface were prepared on ceramic tubes by hydrothermal and vapor diffusion method. The gas‐phase diffusion method can control the heterostructure by adjusting the diffusion time. At room temperature (25 °C), the construction of rich n‐p heterogeneous interface enables the sensor prepared by the nanocomposite to respond to NO 2 , showing the sensing performance with the response value of 28.00 to 10.00 × 10 –6 NO 2 ; the detection limit improved to 0.01 × 10 –6 and the recovery time of 18 s. In this work, the sensing mechanism of NO 2 at heterogeneous interface is analyzed, which provides a promising material for the detection of low concentration NO 2 at room temperature.