In situ TEM investigation of β-FeOOH and α-Fe2O3 nanorods

The investigation of rapidly quenched β-FeOOH and α-Fe2O3 hydrothermal synthesis reaction products, heat treated in situ within a transmission electron microscope, provide direct evidence for the hydrothermal growth mechanism of lenticular α-Fe2O3 nanorods. The transformation of β-FeOOH nanorods into α-Fe2O3 nanoparticles during in situ heating is consistent with the release of Fe3+ ions through β-FeOOH dissolution to supply and promote α-Fe2O3 nucleation and growth. Coarsening of the tips of α-Fe2O3 nanorods through the consumption and coalescence of α-Fe2O3 nanoparticles provides evidence for the hydrothermal growth mechanism of oriented attachment and agglomeration of primary α-Fe2O3 nanoparticles into single crystalline lenticular α-Fe2O3 nanorods.