Flexible morphology-controlled synthesis of mesoporous hierarchical alpha-Fe2O3 architectures and their gas-sensing properties

Mesoporous flower-like and urchin-like alpha-Fe2O3 nanostructures have been successfully synthesized by a simple solution-based reaction and sequential calcination. Detailed experiments demonstrated that the morphology of the hierarchical alpha-FeOOH precursors could be easily controlled by adjusting the experimental conditions including reactant concentration, solvent composition, reaction time, and reaction temperature. On the basis of time-dependent experiments, a multistage growth mechanism for the formation of the alpha-FeOOH super-architectures was proposed. In addition, by virtue of the unique hierarchical mesoporous structure and comparative high specific surface area, these obtained alpha-Fe2O3 nanostructures exhibited enhanced sensing performances to ethanol. This method is expected to be a useful technique for controlling the diverse morphologies of iron oxide superstructures that could meet the demands of a variety of applications, such as gas sensors, lithium-ion batteries, catalysis, waste-water treatment, and pigments.