More effective use of graphene in photocatalysis by conformal attachment of small sheets to TiO2 spheres

Graphene-pasted TiO2 spheres have been prepared successfully by a two-step method including attaching relatively small graphene oxide sheets onto the surface of the modified TiO2 spheres and in-situ photocatalysis reduction of these graphene oxide sheets. Since coated almost totally on the surface of TiO2 spheres, these added graphene sheets are utilized more fully in these as-obtained graphene-pasted composites, which possess more interfaces between graphene and TiO2 and can make better use of the irradiated light compared with that of traditional graphene-involved TiO2 composites. As a result, these graphene-pasted TiO2 spheres always display higher photocatalysis activity in both methylene orange dye degradation and 4-nitrophenol reduction than that of control graphene-TiO2 spheres in the case of the same usage of these carbon sheets, which indicates more efficient use of graphene sheets in these graphene-pasted samples in photocatalysis systems. (C) 2015 Elsevier Ltd. All rights reserved.