Controlled synthesis of mesoporous α-Fe2O3 nanorods and visible light photocatalytic property

Porous α-Fe2O3 nanorods with typical pore size of 2–4 nm were controlled prepared by a facile hydrothermal process of Fe(NO3)3·9H2O aqueous solution in the presence of NaOH, followed by a calcination treatment. Contrast experiments indicate that the morphology and crystalline structure of the hydrothermal products depend greatly on the quantity of NaOH. Hematite nanoparticles and microplates were respectively obtained under conditions without or with excess NaOH. The porous α-Fe2O3 nanorods exhibit a high BET surface area of 105.1 m2 g−1 and a pore volume of 0.13 m3 g−1. UV–vis measurement shows wide absorption to visible light and an obvious blue-shift of the adsorption edge due to the quantum size effect. The visible-light photocatalytic performances of the as-prepared samples were evaluated by photocatalytic decolorization of methylene blue at ambient temperature. The results indicate that the photocatalytic activity of the porous α-Fe2O3 nanorods is superior to hematite nanoparticles and platelets and exhibit good reusable feature. The photocatalytic process of porous structure is determined to be pseudo-first-order reaction with apparent reaction rate constant of 1.04 × 10−2 min−1. And the optimum photocatalyst dosage is 20 mg per 100 mL of dye solution. The porous α-Fe2O3 nanorods are considered potential photocatalyst for practical application due to the excellent photocatalytic behavior and good reusability.