ZnO microspheres-reduced graphene oxide nanocomposite for photocatalytic degradation of methylene blue dye.

In this work, ZnO microspheres-reduced graphene oxide (rGO) nanocomposites were synthesized via a simple solution method and used for the photodegradation of methylene blue (MB) dye from water under UV light. The SEM and TEM observations demonstrate that the microsphere morphologies of the ZnO microspheres-rGO nanocomposite is composed of ZnO microspheres anchored on rGO sheets, confirming the formation of ZnO microspheres-rGO composites. Raman spectra and X-ray photoelectron spectroscopy reveal that both of the reduction of GO tight contact between ZnO and rGO are achieved during the high temperature calcination process. During the photocatalytic test, in comparison with ZnO microspheres and P25 TiO2, the ZnO microspheres-rGO nanocomposite shows improved photodegradation of MB dye, because the rGO sheets could reduce the charge recombination in electron-transfer processes. According to the scavenger experiments, the possible MB degradation mechanism is contributed mainly to the generation of active species induced by the photogenerated holes (h + ) and superoxide radicals ( O 2 − ). [ABSTRACT FROM AUTHOR]