The α-Fe₂O₃/g-C₃N₄ composite as an efficient heterogeneous catalyst with combined Fenton and photocatalytic effects

Integration of Fenton and photocatalytic processes in one reaction system may increase the degradation efficiency in wastewater treatments. In this work α- Fe₂O₃/g-C₃N₄ composites with different mass percentages of α-Fe₂O₃ have been prepared in order to catalyze the Fenton and photocatalytic reactions simultaneously. The catalytic efficiency is greatly boosted in the presence of H₂O₂ under visible-light irradiation compared with single Fenton or photocatalytic reactions. The composite with 0.38% α-Fe₂O₃ shows the best catalytic efficiency with a reaction rate constant of 0.10 min⁻¹ in the degradation of rhodamine B, which is about 8.4 and 3.7 times higher than that of pure α-Fe₂O₃ and pure g-C₃N₄ under the same conditions, respectively. This enhancement of the composites should be ascribed to a synergetic effect between α-Fe₂O₃ and g-C₃N₄. Moreover, a reasonable catalytic mechanism for the α-Fe₂O₃/g-C₃N₄ composite has been proposed.