▎ 摘　　要

Graphene-TiO2 composite photocatalysts, which are very promising in many fields such as optoelectronics, electrode materials and lithium-ion batteries, have attracted much attention in recent years. However, a proper design of graphene-TiO2 photocatalysts requires a systematic study of graphene functions for photocatalytic activity enhancement. It is evident that the enhancement may depend on the structural of graphene, the graphene-TiO2 interface, the nanoscale morphologies, surface area and more. These factors are highly dependent on the preparation method. Herein, in this article, we show two synthetic strategies with three routes to prepare the graphene-TiO2 composite films with spray coating method. The effects of structural differences of graphene and the preparation strategies on the microstructure and the photocatalytic performance of the graphene-TiO2 composite films under the same condition were systematically investigated. The results showed that both of the structure characteristics of graphene including the electron transport ability and specific surface area, and the interfacial contact between graphene nanosheets and TiO2 nanoparticles have important effects on the photocatalytic properties of materials. It is hoped that these experimental results can be applied as a background source to understand the underlying mechanism of the photocatalytic activity enhancement and construct more efficient graphene-TiO2 photocatalysts.