Photo-Fenton reaction and H2O2 enhanced photocatalytic activity of α-Fe2O3 nanoparticles obtained by a simple decomposition route

α-Fe2O3 nanoparticles with different sizes were successfully synthesized by a simple SDS-assisted grinding reaction and subsequent heating treatment process. Effects of calcination temperatures on crystal structure, optical and photocatalytic properties of the products were investigated by TG-DSC, FTIR, XRD, TEM, HRTEM, and UV–Vis techniques. Results showed that growth of the α-Fe2O3 nanoparticles was very slow, and the average crystallite size gradually increased with increasing calcination temperatures. Optical measure and calculation showed that there is an increasing trend for the band gap with increase of calcination temperature. The α-Fe2O3 nanoparticles obtained at 500 °C revealed higher photocatalytic degradation efficiency for MB than the other samples, attributing to the optimal value between transiting electrons and recombination of electron-hole pairs. Radical scavengers experiments implied that ·OH and e− played important roles in the photocatalytic process. The photodegradation time was greatly shortened, and the photocatalytic efficiency was further enhanced and raised to over 90% after adding H2O2, which is due to generation of a large number of the highly oxidative ·OH by photo-Fenton reaction.