Highly Sensitive NO2 Gas Sensor with a Low Detection Limit Based on Pt-modified MoS2 Flakes

Slow response/recovery speed and high detection limit have always been bottlenecks for MoS2-based gas sensors to solve. Herein, MoS2 flakes are prepared via a hydrothermal route. The autoclave temperature is adjusted to acquire the best crystallinity of MoS2. Pt doping is utilized to improve the gas sensing properties of MoS2 flakes to NO2. The results show that the optimized autoclave temperature and Pt modification greatly enhance the gas response of the MoS2-based sensors. The sensors exhibit high sensitivity, good repeatability, excellent selectivity, a low detection limit of 0.1 ppm, and a fast response/recovery time of 35 s/210 s to 32 ppm NO2 at 157 degrees C. Our work provides a helpful design thought for optimizing the gas sensing properties of MoS2-based sensors.