Fe 2 O 3 nanoparticles with diameters in the 7–18 nm range have been synthesized via thermolysis of polyvinyl alcohol (PVA) gels prepared under alkaline pH by adding Fe 3+ ions into warm aqueous solutions of PVA. While calcinations at 400 °C, 500 °C and 600 °C give γ-Fe 2 O 3 as the pure product, α-Fe 2 O 3 is obtained by heating the gel at 700 °C. It is found that the calcination temperature has a pronounced effect on the nature of the oxide produced but has little effect on particle size. The resultant Fe 2 O 3 nanomaterials are ferromagnetic with moderate coercivities. Preliminary investigations suggest that hematite (α-Fe 2 O 3 ) nanoparticles effectively catalyze the epoxidation of styrene with tert-butyl hydroperoxide (TBHP) as the terminal oxidant.
Bepari, R. A., Bharali, P., & Das, B. K. (2017). Controlled synthesis of α- and γ-Fe 2 O 3 nanoparticles via thermolysis of PVA gels and studies on α-Fe 2 O 3 catalyzed styrene epoxidation. Journal of Saudi Chemical Society, 21, S170–S178. https://doi.org/10.1016/j.jscs.2013.12.010