High-performance room-temperature NO2 gas sensors enabled by 0D SnO2/1D WO3 heterostructures for wearable applications

The sensor for nitrogen dioxide (NO2) detection plays a crucial role in environmental monitoring and human health. However, traditional oxide-based NO2 sensors often suffer from high operating temperatures, low sensitivity, and inherent rigidity. In this work, a high-performance, wearable NO2 gas sensor that can work at room temperature was developed based on a nanocomposite of single-crystal tungsten oxide (WO3) and tin dioxide (SnO2). The results show that the fabricated SnO2/WO3 based sensor demonstrates superior performance than the bare WO3 sensors. Specifically, the Sn/W-O-12 based sensor shows a remarkable response of 27.5% to 5 ppm NO2, a low detection limit of 218 ppb at room temperature. Furthermore, its response/recovery time to 0.8 ppm NO2 is 63/38 s, respectively. The sensing device also exhibits excellent humidity resistance (50%) and long-term stability (90 days). The enhanced NO2 sensing performance can be attributed to the formation of heterojunction interface, achieved by the dispersion of small-sized SnO2 particles onto WO3 nanorods, which increases the specific surface area and facilitates charge transfer and gas molecule adsorption on the surface. Additionally, a NO2 gas detection and alarm system was constructed to realize the real-time display and alarm functions. This work contributes to the detection of low concentrations of NO2 at room temperature, fostering the development of wearable sensing systems.