High-performance H2 gas sensor based on Mn-doped α-Fe2O3 polyhedrons from N, N-dimethylformamide assisted hydrothermal synthesis

Transition elements doping metal oxide is of great significance for developing gas sensors with high performance. To achieve this goal, α-Fe2O3 rod and Mn-doped α-Fe2O3 polyhedrons are successfully synthesized by a facile N, N-dimethylformamide assisted hydrothermal method and characterized by several physical techniques. The morphology of α-Fe2O3 is evolved by introducing Mn elements. The performance of the α-Fe2O3 rod and Mn-doped α-Fe2O3 polyhedrons as H2 gas sensors are studied and compared. The Mn/α-Fe2O3-5 polyhedrons sensor exhibit the best performance at optimum operating temperature of 300 °C. The response and recovery times are 10 s/24 s for H2 with a concentration of 200 ppm, which is much faster in contrast to those recently reported H2 gas sensors. Furthermore, α-Fe2O3 rod and Mn-doped α-Fe2O3 polyhedrons show abnormal n-p transition sensing behavior with the change of operating temperature. This work provides a facile method for synthesizing α-Fe2O3 based sensing materials for various sensors applications.