Facile synthesis of reduced graphene oxide/titania composite hollow microspheres based on sonication-assisted interfacial self-assembly of tiny graphene oxide sheets and the photocatalytic property

Sonication-assisted interfacial self-assembly of tiny GO sheets (whose lateral size less than 200 nm) on cationic polyelectrolyte-decorated SiO2 microspheres was achieved, leading to the formation of uniform GO thin layer coated SiO2 microspheres (i.e., SiO2/GO composite microspheres), which possessed high aqueous dispersity. RGO/TiO2 composite hollow microspheres were further one-pot synthesized by solvothermal treatment of SiO2/GO microspheres in the presence of polyvinylpyrrolidone (PVP) using TiF4 as Ti precursor and ethanol/water as a mixed solvent. It was found that PVP and appropriate volume ratio of ethanol to water (v/v = 20:8) were key factors for the fabrication of RGO/TiO2 hollow microspheres with well-defined microspherical hollow structure. The composition, morphology, structure and crystalline phase of RGO/TiO2 hollow microspheres were carefully examined by a series of characterizations like FTIR, UV-vis and Raman spectroscopy as well as XRD, SEM and TEM inspections. Compared with the solvothermally synthesized TiO2 hollow microspheres and blended RGO-TiO2 hollow microspheres, RGO/TiO2 hollow microspheres displayed rather enhanced photocatalytic performance toward the degradation of methylene blue. Moreover, RGO/TiO2 hollow microspheres were durable and robust enough so that they were able to be reused for many times with only a little loss of photocatalytic activity and without the destruction of morphology and structure, exhibiting prominent application potential. This work reveals a facile and versatile synthetic methodology for the fabrication of advanced GO- and RGO-containing hybrid materials with unique shapes and designed properties. (C) 2016 Elsevier B.V. All rights reserved.