Solvothermal synthesis of octahedral and magnetic CoFe(2)O(4)–reduced graphene oxide hybrids and their photo-Fenton-like behavior under visible-light irradiation

We report a facile solvothermal synthesis of novel octahedral CoFe(2)O(4)–reduced graphene oxide (RGO) hybrid and pure CoFe(2)O(4) that were used as heterogeneous photo-Fenton catalysts for the degradation of organic dyes in water. We investigated the structures, morphologies and catalytic activity of both the CoFe(2)O(4) nanoparticles and CoFe(2)O(4)–RGO hybrids. The morphology of CoFe(2)O(4) nanoparticles displays size-dependent shapes changing from granular (or sheet) to octahedral shapes with the introduction of RGO. Compared with bare CoFe(2)O(4), the octahedral CoFe(2)O(4)–RGO hybrids serve as novel bifunctional materials displaying higher saturation magnetization values and excellent heterogeneous activation of H(2)O(2) at nearly neutral pH. The high saturation magnetization (41.98 emu g(−1)) of CoFe(2)O(4)–RGO hybrids aids their separation from the reaction mixture. In addition, the remarkable enhancement in the photo-Fenton activity of the CoFe(2)O(4)–RGO hybrids under visible light irradiation was attributed to the graphene/CoFe(2)O(4) heterojunction, which aided the separation of excited electrons and holes. Furthermore, the CoFe(2)O(4)–RGO hybrids exhibited better removal efficiency for cationic methylene blue (MB) dye than for anionic methyl orange (MO) dye. Meanwhile, the CoFe(2)O(4)–RGO hybrids displayed acceptable photocatalytic stability, and we proposed an activation mechanism of H(2)O(2) by the octahedral CoFe(2)O(4)–RGO hybrids.