Ultra-sensitive NO2 detection at room temperature enabled by ZnO@MoO3 core-shell nanocomposite.

The sensitive detection of NO2 is crucial for environmental monitoring and improving quality of life. Herein, a ZnO@MoO3 core-shell nanocomposite was fabricated via a simple stepwise solution self-assembly and heat-treatment process. Remarkably, the ZnO@MoO3 sensor exhibited a high response value of 5.4 to 2 ppm NO2 at room temperature. Furthermore, it displayed excellent selectivity against interference gases such as CO2, NH3, methanol, ethylene, and trimethylamine, along with outstanding stability and repeatability under varying humidity conditions. The exceptional sensing performance of the ZnO@MoO3 sensor is attributed to the synergistic effects between ZnO and MoO3, as well as the enhanced electron transfer rate enabled by the heterostructures. This work provides an effective strategy for advancing NO2 sensing capabilities in metal oxide composite sensors.