▎ 摘　　要

Reduced graphene oxide/TiO2 microspheres were produced by a non-hydrolytic sol-gel reaction of tetrabutyl orthotitanate and acetone followed by hydrothermal treatment. In the hydrothermal treatment, ammonia was used as a medium solution, and reaction temperature was varied from 120 to 180 degrees C to investigate the effect on crystal phase and morphology of the prepared samples. Prior to the hydrothermal treatment, graphene oxide was introduced into the medium solution as an impurity material. Graphene oxide was characterized using AFM to confirm the formation of single-layer graphene sheet and its image. Prepared catalysts were characterized by XRD, SEM, N-2 adsorption (BET), Raman spectroscopy, FTIR and UV-visible diffuse reflectance spectra. Ammonia as a medium in hydrothermal reaction promoted the formation of nanoflakes and nanorods on the microspheres. Hydrothermal reaction temperature was found to have a significant effect on the morphology and crystal phase of the catalyst. Lower hydrothermal treatment temperature produced amorphous samples with higher surface area that increased methylene blue adsorption capacity significantly. Higher hydrothermal treatment temperature, on the other hand, produced anatase crystal phase TiO2 with lower surface area. Prepared samples at higher treatment temperature showed comparable photocatalytic activity to commercial P25 TiO2 on the photocatalytic degradation of methylene blue under UV-visible light irradiation. The photocatalytic activity of prepared RGO/TiO2 microspheres photocatalysts were further tested using orange II. The preparation method proposed in this study could produce reduced graphene oxide/TiO2 photocatalyst that is promising for use in organic pollutants treatment in water in terms of high photocatalytic activity and easy recovery owing to microsized photocatalyst. (c) 2013 Elsevier B.V. All rights reserved.