Preparation: |
Hematite (a-Fe2O3) was synthesized by transformation of ferrihydrite using a method adapted from [SC91]. In brief, 80 g of Fe(NO3)3·9H2O was dissolved in 1 L of DDI H2O at 90°C and mixed with 1 L of 1 M KOH (heated to 90 °C) in a 2 L polycarbonate bottle (PC). Then, 100 mL of 1 M KHCO3 was mixed with the solution to give a pH of approximately 8. The solution was then heated to 100 °C in the PC bottle for 48 h to allow complete transformation to a-Fe2O3. After the incubation period, the resulting bright red solid was washed with DDI H2O six times to remove residual salts. After drying at approximately 105 °C, the hematite was gently ground using a mortar and pestle. |