Photodegradation of naphthalene over Fe3O4 under visible light irradiation.

Using FeCl3 and FeSO4 as precursors, Fe3O4 were prepared by co-precipitation method via FeCl3 and FeSO4 aqueous solutions successively added to NaOH solution. The sample was proved by X-ray powder diffraction, transmission electron microscope, ultraviolet-visible spectrophotometry and magnetic measurement. The results showed that the prepared Fe3O4 material was composed of an average diameter of about 15 nm particles and nano rods with well-crystallized magnetite and stronger superparamagnetic, getting a saturation magnetization of 49.5 emu g-1. This Fe3O4 material was found to be an effective catalyst for photodegradation of naphthalene with or without H2O2 under visible light irradiation, getting 81.1% and 74.3% degradation rate in these two cases, respectively. The degradation pathway in the absence and presence of H2O2 was analysed via measurement of the distribution of degradation products by GC-MS and adsorption of reactants on the surface of the catalyst by in situ DRIFTS spectra.