Preparation of highly efficient and magnetically recyclable Fe3O4@C@Ru nanocomposite for the photocatalytic degradation of methylene blue in visible light

Herein, a kind of Fe 3 O 4 @C@Ru hybrid nanocomposites was successfully synthesized by a three-step process. The as-prepared products were characterized by X-ray powder diffraction, transmission electron microscopy , high-resolution transmission electron microscopy , energy dispersive spectroscopy , X-ray photoelectron spectroscopy, UV–visible diffuse reflectance spectrometry and photoluminescence emission spectrometry . The Ru nanoparticles loaded on the surface of carbon shell on Fe 3 O 4 @C nanospheres were nearly spherical with an average diameter of less than 5 nm. The photodegradation of methylene blue (MB) was carried out under the irradiation of simulated visible light to investigate the catalytic activity of the introduced nanomaterial . The results showed that the catalytic activity of Fe 3 O 4 @C@Ru nanocomposites in the MB photodegradation was higher than that of Fe 3 O 4 nanospheres or of Fe 3 O 4 @C nanospheres, as they could degrade 92.70% of the dye in 140 min of simulated sunlight irradiation without any other oxidant or reductant. The photodegradation reaction was first-order with the rate constant of 0.0176 min −1 at room temperature . The degradation rate of Fe 3 O 4 @C@Ru nanocomposites decreased very slightly after five cycles. Furthermore, they could be easily separated and recycled by using an external magnet. It indicated that the magnetically recoverable Fe 3 O 4 @C@Ru nanocomposites had a very broad application prospect in the field of environmental protection.