Supporting information from Photodegradation of naphthalene over Fe<sub>3</sub>O<sub>4</sub> under visible light irradiation

Using FeCl<sub>3</sub> and FeSO<sub>4</sub> as precursors, Fe<sub>3</sub>O<sub>4</sub> were prepared by co-precipitation method via FeCl<sub>3</sub> and FeSO<sub>4</sub> aqueous solutions successively added in 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 Fe<sub>3</sub>O<sub>4</sub> 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<sup>−1</sup>. This Fe<sub>3</sub>O<sub>4</sub> material was found to be an effective catalyst for photodegradation of naphthalene with or without H<sub>2</sub>O<sub>2</sub> 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 H<sub>2</sub>O<sub>2</sub> was analysed via measurement of the distribution of degradation products by GC-MS and adsorption of reactants on the surface of the catalyst by <i>in situ</i> DRIFTS spectra.