Core-Shell Nanostructure of alpha-Fe2O3/Fe3O4: Synthesis and Photocatalysis for Methyl Orange

Fe3O4 nanoparticle was synthesized in the solution involving water and ethanol. Then, alpha-Fe2O3 shell was produced in situ on the surface of the Fe3O4 nanoparticle by surface oxidation in molten salts, forming alpha-Fe2O3/Fe3O4 core-shell nanostructure. It was showed that the magnetic properties transformed from ferromagnetism to superparamagnetism after the primary Fe3O4 nanoparticles were oxidized. Furthermore, the obtained alpha-Fe2O3/Fe3O4 core-shell nanoparticles were used to photocatalyse solution of methyl orange, and the results revealed that alpha-Fe2O3/Fe3O4 nanoparticles were more efficient than the self-prepared alpha-Fe2O3 nanoparticles. At the same time, the photocatalyzer was recyclable by applying an appropriate magnetic field.