Effect of preparation method on the physical and catalytic property of nanocrystalline Fe2O3

Nanocrystalline Fe2O3 was prepared by five different methods. The samples were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). It is found that pure single-phase of α-Fe2O3 crystal could be gained via thermal decomposition and ultrasonic-precipitation method, while both α-Fe2O3 and γ-Fe2O3 are obtained by the other methods. The morphologies and particle sizes of the samples obtained are approximate except that by thermal decomposition. Compared to α-Fe2O3, γ-Fe2O3 possesses more surface oxygen species “O−”. The activity test indicates that surface oxygen species “O−” plays a crucial role in the hydroxylation of benzene to phenol with hydrogen peroxide as oxidant.