Gas sensing performance of Fe2O3-Co3O4 nano heterojunctions for ethanol detection

In this paper, the development of a conductometric ethanol sensor based on Fe2O3/Co3O4 nano-heterostructures, synthesized by sol–gel auto combustion reaction method, is reported. The as-synthesized composite nanoparticles with different Fe2O3/Co3O4 molar ratio were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectra (EDX), and diffuse reflectance spectroscopy (DRS). The electrical and ethanol sensing properties of the Fe2O3/Co3O4 nano-heterostructures were investigated. The results reveal that, when operated at the optimal working temperature of 250 ℃, the Fe2O3/Co3O4 (0.6:1 molar ratio) based sensor displays significantly improved ethanol sensing ability compared to pristine Co3O4. Good sensitivity, short response/recovery time, repeatability, and selectivity are the distinctive characteristics of the sensor developed. The improved ethanol sensing performances are attributed to the presence of p-n heterojunction in the Fe2O3/Co3O4 nano-heterostructures synthesized.