Synthesis, characterization and gas sensing properties of undoped and Zn-doped γ-Fe2O3-based gas sensors

In this study, undoped and Zn-doped γ-Fe2O3 nanopowders have been prepared using Fe(NO3)3·9H2O and Zn(NO3)2·6H2O as starting materials and lauryl alcohol as anhydrous medium. Thermo-gravimetric analysis (TGA), differential thermal analysis (DTA), X-ray diffraction (XRD) and transmission electron micrograph (TEM) were employed to characterize the products. Sensitivity characteristics of the undoped and Zn-doped γ-Fe2O3 semiconductor gas sensors have been investigated. The results show that both of the undoped and 15 mol% Zn-doped γ-Fe2O3-based gas sensors present good sensitivity and selectivity to acetone and ethanol in presence of CH4, H2 and CO at the operating temperatures of 240 and 270 °C, respectively. After being doped with 15 mol% Zn addition, the γ-Fe2O3-based gas element displays higher sensitivity and selectivity as well as shorter response-recovery time compared with the undoped, suggesting that the promoting effect of ZnO is excellent. So, it seems that the γ-Fe2O3-based gas sensor doped with 15 mol% Zn is expected to be a promising sensor for detecting acetone and ethanol.