Temperature-dependent linear or nonlinear gas sensing characteristics of In2O3 mixed α-Fe2O3 nanorods with high sensitivity

Highly sensitive gas sensors are realized from In2O3 mixed α-Fe2O3 nanorods. At 200 °C, the sensitivity of the sensors upon exposure to 200 ppm ethanol is 31.3, and the sensors exhibit linear dependence of the sensitivity on the ethanol concentration at 100 °C and 200 °C. In contrast, nonlinear gas sensing characteristics are observed at 300 °C and 400 °C. The relationship between sensitivity and ethanol concentration is discussed by using the conduction model, and the experimental data are in good agreement with the obtained equations. Our results imply that In2O3 mixed α-Fe2O3 nanorods are good candidates for nano-scale gas sensors and the relationship between sensitivity and ethanol concentration is significantly influenced by temperatures.

► In2O3 mixed α-Fe2O3 nanorods have been firstly synthesized by a simple two-step method. The crystal phase and morphology of the products were characterized by XRD and SEM which confirm that α-Fe2O3 and In2O3 crystals have relatively pure phases. ► Highly sensitive gas sensors are realized from In2O3 mixed α-Fe2O3 nanorods. At 200 °C, the sensitivity of the sensors upon exposure to 200 ppm ethanol is 31.3, and the sensors exhibit linear dependence of the sensitivity on the ethanol concentration. ► The relationship between sensitivity and ethanol concentration is discussed by using the conduction model, and the experimental data are in good agreement with the obtained equations.