Well-Dispersed Fe2O3 Nanoparticles on g-C3N4 for Efficient and Stable Photo-Fenton Photocatalysis under Visible-Light Irradiation

In this study, a highly efficient heterogeneous photo-Fenton system (Fe2O3/g-C3N4/H2O2/visible light) has been developed. The heterogeneous catalyst Fe2O3/g-C3N4 in this system was successfully prepared by growing Fe2O3 nanoparticles on the surface of g-C3N4. The Fe2O3 nanoparticles could achieve high dispersion on the surface of g-C3N4 and form a heterojunction with g-C3N4 to improve the charge separation. In addition, the combination of the Fenton's reagent Fe2O3/H2O2 and the photocatalyst g-C3N4 greatly enhances the rate of the Fenton's reaction with the assistance of the photocatalytic process. The results showed that the Fe2O3/g-C3N4 catalyst had a superior catalytic activity as compared with the single component of Fe2O3 or g-C3N4 and the mechanical mixture of Fe2O3 and g-C3N4. The catalyst prepared with 3 mL of FeCl3 aqueous solution shows the best photo-Fenton photocatalytic efficiency with a reaction rate constant of 0.02461 mgL(-1)min(-1), which is about 45.4, 8.4 and 7.2 times larger than that of pure Fe2O3 (0.0005418 mgL(-1)min(-1)), pure g-C3N4 (0.00294 mgL(-1)min(-1)) and the mechanically mixed Fe2O3/g-C3N4 (0.0034 mgL(-1)min(-1)), respectively. A possible mechanism for the visible-light-irradiated photo-Fenton photocatalysis is proposed, and the Fe2O3/g-C3N4 catalyst exhibited stable performance without obvious loss of catalytic activity after four successive runs, showing a good application prospect for the photo-oxidative degradation of organic contaminants in wastewater.