Highly visible-light-responsive CuO/rGO decorated with FeO@SiO nanoparticles as a magnetically recyclable photocatalyst.

The rhombic dodecahedral cuprous oxide-reduced graphene oxide/core-shell FeO@SiO composites (denoted as rCuO-rGO/FeO@SiO) are successfully synthesized facilely via a wet-chemical route. The resulting rCuO-rGO/FeO@SiO combines the unique structure of CuO, electronic characteristics of reduced graphene oxide (rGO) and magnetic property of FeO@SiO to be an effective and recoverable photocatalyst for the degradation of methyl orange (MO). The obtained results show that rCuO-rGO/FeO@SiO is capable of completely degrading MO in the presence of a very low catalyst concentration (0.125 g l) within a short time (60 min) under visible light compared to the reported catalysts. The observations may be due to the distinctive interfacial structures of rhombic dodecahedral CuO nanoparticles connected to rGO sheets that can enhance the separation of photogenerated electron-hole pairs, stabilize the CuO and increase MO adsorption, as evidenced by a variety of spectroscopic analyses (transmission electron microscopy, x-ray photoelectron spectroscopy and photoluminescence). More importantly, these efficient photocatalysts can easily be recovered under a magnetic field and remain highly photoactive towards the degradation of MO after cyclic tests, and may be promising photocatalysts for practical applications in the solar-energy purification of wastewater.