Morphology-controlled hydrothermal synthesis and photocatalytic Cr(VI) reduction properties of α-Fe2O3

Hematite (α-Fe2O3) with different morphologies were synthesized via hydrothermal treatment of ferric acetylacetonate in deionized water, simply by changing the hydrothermal temperature and time. Their photocatalytic performance was assessed based on the photocatalytic reduction of aqueous Cr(VI) under visible-light. It was found that the α-Fe2O3 nanorods synthesized at 175 °C for 2 h (Fe2O3-175 °C/2 h) had better photocatalytic activity than the other products. Moreover, Fe2O3-175 °C/2 h also demonstrated good photocatalytic reusability and stability. The reasons underlying the photocatalytic activity difference of different morphologies of α-Fe2O3 were proposed, by comparing their specific surface area, photoabsorption capability, and photogenerated charge transfer and separation efficiency. Various factors influencing the photocatalytic reduction of Cr(VI) by Fe2O3-175 °C/2 h were also investigated. Finally, Fe2O3-175 °C/2 h was tested for photocatalytic treatment of the diluted black chromium electroplating solution under visible-light, and a good treatment result was obtained. Hence, α-Fe2O3 nanorods have great potential for photocatalytic treatment of Cr(VI) wastewater.