Nanocasting synthesis and gas-sensing behavior of hematite nanowires

The dispersed and uniform hematite nanowires (alpha-Fe2O3 NWs) with the different diameter were synthesized using SBA-15 as hard templates by the nanocasting method, and the diameter of alpha-Fe2O3 NWs was about 4, 6 and 8 nm, respectively. The BET surface area of alpha-Fe2O3 NWs changed a little, while the bandgap decreased from 2.07, 2.03 to 1.91 eV with the increasing diameter according to quantum size effect. Compared all samples, the sensitivity of alpha-Fe2O3 NWs based gas-sensors increased from 10.64 to 11.43 with the bandgap and BET surface area alpha-Fe2O3 NWs in 100 ppm ethanol at 300 degrees C, and the response recovery time was also improved for the good crystallinity. It's concluded that the surface area greatly affected the gas-sensing performance of alpha-Fe2O3 NWs based sensors, while the bandgap and crystallinity also influenced the gas-sensing behavior to some extent. The alpha-Fe2O3 NWs based gas-sensors exhibited the high sensitivity, fast response recovery and good selectivity to ethanol. (C) 2016 Elsevier B.V. All rights reserved.