One-step hydrothermal synthesis of Sn-doped α-FeOnanoparticles for enhanced photocatalytic degradation of Congo red

We report on the synthesis of Sn-doped hematite nanoparticles（Sn-α-Fe2 O3 NPs） by the hydrothermal method.The prepared Sn-α-Fe2 O3 NPs had a highly pure and well crystalline rhombohedral phase with an average particle size of 41.4 nm.The optical properties of as-synthesized α-Fe2 O3 NPs show a higher bandgap energy（2.40-2.57 eV） than that of pure bulk aFe2 O3（2.1 eV）.By doping Sn into α-Fe2 O3 NPs,the Sn-doped hematite was observed a redshift toward a long wavelength with increasing Sn concentration from 0% to 4.0%.The photocatalytic activity of Sn-doped α-Fe2 O3 NPs was evaluated by Congo red（CR） dye degradation.The degradation efficiency of CR dye using Sn-α-Fe2 O3 NPs catalyst is higher than that of pure α-Fe2 O3 NPs.The highest degradation efficiency of CR dye was 97.8% using 2.5% Sn-doped α-Fe2 O3 NPs catalyst under visible-light irradiation.These results suggest that the synthesized Sn-doped α-Fe2 O3 nanoparticles might be a suitable approach to develop a photocatalytic degradation of toxic inorganic dye in wastewater.