Ultrasensitive NO2 Gas Sensors Based on Layered α-MoO3 Nanoribbons

The detection and monitoring of nitrogen dioxide (NO2) plays a vital role in the environmental, healthcare, farming, and industrial sectors. However, the development of NO2 gas sensors with simultaneously high sensitivity, reversibility, low detection limit, and excellent selectivity remains challenging. In this work, an ultrasensitive NO2 gas sensor with superb selectivity and reversibility is demonstrated based on alpha-phase molybdenum trioxide (alpha-MoO3). Nanoribbons of alpha-MoO3 are synthesized via vapor phase transport (VPT) and systematically characterized using a combination of advanced characterization probes. At an optimal operating temperature of 125 degrees C, the alpha-MoO3-based sensor shows a very high sensitivity toward NO2 with a detection limit as low as 24 ppb, while also exhibiting excellent selectivity and reversibility. Such impressive performance originates from the layered nature of the alpha-MoO3 nanoribbons as well as the hierarchical assembly of the nanoribbons as the sensing layer. The study demonstrates a facile sensing platform based on alpha-MoO3 for ultrasensitive and selective NO2 gas sensing.