Edge-enriched MoS2 nanosheets modified porous nanosheet-assembled hierarchical In2O3 microflowers for room temperature detection of NO2 with ultrahigh sensitivity and selectivity

Nitrogen dioxide (NO2) is one of the most hazardous toxic pollutants to human health and the environment. However, deficiencies of low sensitivity and poor selectivity at room temperature (RT) restrain the application of NO2 sensors. Herein, the edge-enriched MoS2 nanosheets modified porous nanosheets-assembled three-dimensional (3D) In2O3 microflowers have been synthesized to improve the sensitivity and selectivity of NO2 detection at RT. The results show that the In2O3/MoS2 composite sensor exhibits a response as high as 343.09-5 ppm NO2, which is 309 and 72.5 times higher than the sensors based on the pristine MoS2 and In2O3. The composite sensor also shows short recovery time (37 s), excellent repeatability and long-term stability. Furthermore, the response of the In2O3/MoS2 sensor to NO2 is at least 30 times higher than that of other gases, proving the ultrahigh selectivity of the sensor. The outstanding sensing performance of the In2O3/MoS2 sensor can be attributed to the synergistic effect and abundant active sites originating from the p-n heterojunction, exposed edge structures and the designed 2D/3D hybrid structure. The strategy proposed herein is expected to provide a useful reference for the development of high-performance RT NO2 sensors.