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

In this paper, α-Fe 2 O 3 was prepared by hydrothermal and chemical precipitation methods, respectively, and its gas sensing properties toward CH 4 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-Fe 2 O 3 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 CH 4 . In addition, the sensing mechanism was discussed and simulated by first-principles calculation. The results revealed the higher surface adsorption energy of α-Fe 2 O 3 , which verified the experimental conclusions of our work. Our research suggests that α-Fe 2 O 3 is a promising candidate for CH 4 gas sensing in many fields such as mining safety and environmental monitoring.