LAUSR

Abstract Seven 0D-3D α-Fe2O3 nanostructures with different shapes and sizes have been prepared via a solvothermal route and subsequent calcination. It was found that the dosage of hexamethylenetetramine (HMTA) and the kind of solvent played determinant roles in the controlled synthesis of α-Fe2O3 nanostructures. Increasing the amount of HMTA from 0.070 g to 0.420 g, the morphology of α-Fe2O3 product evolves from 1D nanobelt, 2D nanosheet to 3D nanoflower with sizes ranging from 4 μm to 650 nm. Changing the kind of solvent with various chain lengths or polarity, 0D α-Fe2O3 porous nanospheres, rhombohedra and cylinder microstructure can be obtained. Based on the experimental results, the possible formation mechanism of various dimensional products was speculated. The different gas-sensing behaviors that related with the microstructures of the as-prepared α-Fe2O3 samples were also investigated. The fabricated gas sensors all present good stability and high selectivity towards acetone gas, and the comparable responses to acetone should be due to the variation in their size, morphology and specific surface area (SSA). In addition, the gas-sensing conductive mechanism based on the α-Fe2O3 samples was also proposed.