Synthesis, characterization and catalytic performance of magnetic La0.7Sr0.3MnO3/α-Fe2O3 with p-n heterojunction structure

In this study, a solar-driven photocatalyst La0.7Sr0.3MnO3/alpha-Fe2O3 (20%) with p-n heterojunction structure was synthesized and characterized. The magnetic, photocatalytic properties, Fenton-like action and the synergistic effect of the photocatalysis and Fenton-like on methyl orange (MO) degradation of La0.7Sr0.3MnO3/alpha-Fe2O3 (20%) were also investigated. Results show that p-n heterojunction was formed, and it has considerable photocatalytic properties under ultraviolet light and solar irradiation. More importantly, La0.7Sr0.3MnO3/alpha-Fe2O3 (20%) also exhibits Fenton-like catalytic performance in the presence of H2O2 and oxalic acid (OA). The main reactive radicals of the La0.7Sr0.3MnO3/alpha-Fe2O3-H2O2-OA-sunlight system are h(+), (OH)-O-center dot and O-center dot(2)-. The chemical oxygen demand removal rate of MO wastewater in La0.7Sr0.3MnO3/alpha-Fe2O3 (20%)-H2O2-oxalic acid-sunlight system reached 72.4%; the value was higher than that of the sum of single photocatalysis (34.5%) and Fenton-like-dark system (27.6%), indicating that there is a synergistic effect between the photocatalysis and Fenton-like on MO degradation. In addition, La0.7Sr0.3MnO3/alpha-Fe2O3 (20%) displays approximately superparamagnetism and has higher saturated magnetization (M-s), low coercive force and residual magnetism. So it can be easily recovered by an external magnetic field and can be reused 6 times. It was anticipated that La0.7Sr0.3MnO3/alpha-Fe2O3 (20%) with p-n heterojunction structure is a stable and reusable solar-light-driven magnetic photocatalyst and has great potential applications for wastewater treatment.

Automated summary

A solar-driven photocatalyst La0.7Sr0.3MnO3/alpha-Fe2O3 (20%) with p-n heterojunction structure was synthesized and investigated for its significant photocatalytic properties and Fenton-like catalytic performance, demonstrating a synergistic effect on methyl orange degradation.