α-Fe2O3 hierarchically nanostructured mesoporous microspheres: Surfactant-free solvothermal combined with heat treatment synthesis, photocatalytic activity and magnetic property

Abstract

A surfactant-free solvothermal combined with heat treatment method is reported to prepare α-Fe₂O₃ hierarchically nanostructured mesoporous microspheres. Firstly, a surfactant-free solvothermal method is adopted to prepare the precursors of ferrous tartrate (C₄H₄O₆Fe) hierarchical microspheres using Fe(NO₃)₃ and tartaric acid in dimethylformamide (DMF) or in mixed solvents of water and DMF at 180 °C for 18 h. The morphology and size of the precursors of ferrous tartrate can be controlled through adjusting the experimental conditions. Secondly, by means of heat treatment of the precursors at 400 or 500 °C for 3 h, the precursors are transformed to α-Fe₂O₃ hierarchically nanostructured mesoporous microspheres. The α-Fe₂O₃ hierarchically nanostructured mesoporous microspheres exhibit high photocatalytic activities over salicylic acid. Relatively high coercivity values are obtained for α-Fe₂O₃ hierarchically nanostructured mesoporous microspheres. The α-Fe₂O₃ hierarchically nanostructured mesoporous microspheres reported herein have a potential application in a variety of areas such as catalysis.