A Highly Sensitive Room-Temperature NO2 Gas Sensor based on Porous MnO2/rGO Hybrid Composites

Background: The NOX (e.g. NO2) is harmful to human health and environmental quality. It is of great interest to monitor the hazardous NOx with a simple, reliable, and sensitive sensor. Currently, the commonly used detection methods have disadvantages of complex operation, unstable cycling performance and low sensitivity. Objective: In this paper, rGO coated Ni foam supported MnO2 is synthesized to develop a more advanced detection method for the rapid analysis of NO2. Methods: A three-dimensional nickel foam supported MnO2 and rGO (MnO2/rGO@NF) was prepared by a hydrothermal method for application in binder-free electrode of NO2 sensor. Results: The MnO2/rGO@NF composite displayed significantly better NO2 sensing performance compared to single MnO2@NF or rGO@NF. The excellent sensing response (5.9%) as well as high cycling stability were observed in the presence of 50.0 ppm NO2 at room temperature. Furthermore, the mechanism of the great gas-sensing performance was also investigated by the density functional theory (DFT). Conclusion: These results were very important to further design and prepare new sensitive materials applied in binder-free electrode of gas NO2 sensors.