Fabrication of shape-controlled α-Fe2O3 nanostructures by sonoelectrochemical anodization for visible light photocatalytic application

In this study, various α-Fe2O3 (hematite) nanostructures were prepared on Fe foils by sonoelectrochemical anodization method. The principal component of the electrolyte was ethylene glycol contained 0.3 wt.% NH4F. The α-Fe2O3 surface shapes have been controlled by varying the water volume ratios (WVR) in electrolyte solution. The α-Fe2O3 samples were characterized by field emission scanning electron microscopy, energy-dispersive x-ray spectroscopy, grazing incidence x-ray diffraction, and UV–vis absorbance spectra. As the variation of WVR, the α-Fe2O3 samples showed different surface morphologies of nanoparticles, nanorods, nanoporous, and nanoleaflets. The visible light photocatalytic activity of the α-Fe2O3 nanostructures was investigated by degradation of methylene blue, and the α-Fe2O3 nanoporous sample showed the best photocatalytic performance.