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.