Study on Methane-Sensing Properties of α-Fe2O3 Nanoparticles Prepared by Hydrothermal and Chemical Precipitation Methods

In this paper, α-Fe2O3 was prepared by hydrothermal and chemical precipitation methods, respectively, and its gas sensing properties toward CH4 were systematically studied. The larger specific surface area of the materials provided them potential and considerable gas adsorption abilities. The results of gas-sensing measurements indicated the synthesized α-Fe2O3 materials presented a p-type conductive nature. The sensitivities of the devices based on the different material fabrication methods were measured to be 195% and 214%, respectively, at 370°C for the concentration of 2000 ppm CH4. In addition, the sensing mechanism was discussed and simulated by first-principles calculation. The results revealed the higher surface adsorption energy of α-Fe2O3, which verified the experimental conclusions of our work. Our research suggests that α-Fe2O3 is a promising candidate for CH4 gas sensing in many fields such as mining safety and environmental monitoring.