Ultrasensitive NO2 Gas Sensors Based on Layered α‐MoO3 Nanoribbons

Abstract The detection and monitoring of nitrogen dioxide (NO 2 ) plays a vital role in the environmental, healthcare, farming, and industrial sectors. However, the development of NO 2 gas sensors with simultaneously high sensitivity, reversibility, low detection limit, and excellent selectivity remains challenging. In this work, an ultrasensitive NO 2 gas sensor with superb selectivity and reversibility is demonstrated based on α‐phase molybdenum trioxide (α‐MoO 3 ). Nanoribbons of α‐MoO 3 are synthesized via vapor phase transport (VPT) and systematically characterized using a combination of advanced characterization probes. At an optimal operating temperature of 125 °C, the α‐MoO 3 ‐based sensor shows a very high sensitivity toward NO 2 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 α‐MoO 3 nanoribbons as well as the hierarchical assembly of the nanoribbons as the sensing layer. The study demonstrates a facile sensing platform based on α‐MoO 3 for ultrasensitive and selective NO 2 gas sensing.