Effects of precursors on the phase, magnetic and photocatalytic properties of nano Fe2O3 synthesized by low temperature calcination

Abstract By calcining ferric acetylacetonate (Fe(ACAC)3), Fe(NO3)3·9H2O and FeCl3·6H2O in air at 300 °C for 5 h, maghemite (γ-Fe2O3) nanoparticles, hematite (α-Fe2O3) nanoparticles and α-Fe2O3 nanoflakes were synthesized, respectively. The γ-Fe2O3 nanoparticles demonstrated far stronger magnetism (remanent magnetization (Mr) = 9.9 emu/g) than α-Fe2O3 nanoparticles (Mr = 0.06 emu/g) and nanoflakes (Mr = 0.13 emu/g) at room temperature. For photocatalytic reduction of aqueous Cr(VI) in the presence of visible-light and citric acid, the performance of different Fe2O3 samples was found to be in the order of α-Fe2O3 from FeCl3·6H2O > γ-Fe2O3 from Fe(ACAC)3 > hydrothermally synthesized α-Fe2O3 nanorods > α-Fe2O3 from Fe(NO3)3·9H2O > hydrothermally synthesized α-Fe2O3 nanoparticles. This work reveals the decisive role of precursors in the phase, magnetic and photocatalytic properties of low temperature calcination-synthesized Fe2O3. The phase-tunable synthesis of nano Fe2O3 by low temperature calcination of easily available precursors is simple, cost-effective and practical for large scale industrial production.