Ultrasensitive NO2 gas sensor based on MoS2 modified urchin-like Bi2S3 heterojunction

Bi2S3/MoS2 was prepared by the microwave hydrothermal method. The scanning electron microscope (SEM) results show that a large number of Bi2S3 nanorods form urchin-like morphology through self-assembly, and MoS2 nanorods grow on the surface, so that Bi2S3/MoS2 material has a high specific surface area. In addition, gas sensing performance of Bi2S3/MoS2 from 100 ppb to 10 ppm was performed. Bi2S3/MoS2 shows the characteristics of good selectivity, fast response and high sensitivity. The response and recovery time of the sensor was less than 25 s for 10 ppm at 200 °C. The sensing mechanism of Bi2S3/MoS2 was discussed. MoS2 had strong adsorption capacity, and the composite material was easier to contact with nitrogen dioxide gas than pure Bi2S3. The composite of Bi2S3 and MoS2 formed heterostructures, which generated more active sites on the surface of the material, thus improving the gas sensing response of Bi2S3/MoS2 sensor.