Fe3O4 nanoparticles were first synthesized via a fast precipitation method. CeO2 and Fe3O4– CeO2 nanocomposites then were prepared using hydrothermal method with a green procedure in the presence of lemon extract. The effect of time, pH and applied magnetic field on the size and shape of nanostructures were investigated. The prepared products were characterized using X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. Vibrating sample magnetometer was used to study the magnetic property of the products. The results illustrated super-paramagnetic behaviour of Fe3O4 nanoparticles. The photo-catalytic behaviour of Fe3O4– CeO2 nanocomposites was evaluated using the degradation of two azo dyes under ultraviolet light irradiation. The results show that the prepared nanocomposites have potential application for magnetic and photo-catalytic performance.
