Synthesis, characterization and photo-Fenton catalytic activity of magnetic CuFe2O4/Fe2O3 materials

Abstract

In this work, we proposed to immobilize Fe₂O₃ nanoparticles on the surface of magnetic CuFe₂O₄ particles by a facile impregnation – annealing method at different annealing temperatures (200, 300, 400 and 500°C) in order to create new heterogeneous photo-Fenton catalysts with enhanced catalytic performance for the oxidation of organic dyes. The influences of annealing temperatures used in the synthesis procedure on the phase composition, the morphology, the particle size and the surface functional groups of our catalysts were investigated by XRD, FE-SEM and FTIR techniques, respectively. The photo-Fenton catalytic performance was evaluated by the degradation of methylene blue under both UVA and visible light illumination in the presence of H₂C₂O₄ as radical-producing source. According to the experimental results, Fe₂O₃ nanoparticles were successfully coated on CuFe₂O₄ surface, which successfully formed the α-Fe₂O₃ phase in the phase composition and also increased the Fe³⁺ content on the surface. As a consequence, the rate constant of photo-Fenton catalytic degradation of methylene blue over these samples were clearly improved. More especially, owing to the good magnetic property of CuFe₂O₄ component, our CuFe₂O₄/Fe₂O₃ samples were easy to be separated from the solution by a magnet, making them more feasible in practical applications of environmental treatment. Among our catalytic samples, the CuFe₂O₄/Fe₂O₃ sample annealed at 300°C showed the best performance with the highest rate constants under both UVA light and visible light. Its catalytic activities was found to be 6.8 times higher than CuFe₂O₄ under UVA light and 2.1 times higher than CuFe₂O₄ under visible light. However, when the annealing temperature was up to 500°C, the catalytic activity was reduced, which can be explained by the growth of particles and the stabilization of surface Fe-O bonds.