Preparation and photocatalytic performance of transparent titania film from monolayer titania quantum dots

By using monolayer titania quantum dots (MTQDs) colloid, a continuous and transparent ultrathin titania film was prepared simply by drop-cast or spray coating method at room temperature. The formation of this even and ultrathin film was not only because of the very thin thickness of two-dimensional MTQDs, but also because of the suppression of coffee-ring effect. The self-assembly behaviors of MTQDs were examined by AFM and the reason for the suppression of coffee-ring effect was discussed in detail. Furthermore, the photocatalytic performance of this MTQDs film was evaluated and an improvement was achieved by loading graphene. Comparison between MTQDs/graphene composite and sphere-shaped nanoTiO 2 /graphene composite indicated that, the face-to-face contact mode between MTQDs and graphene may contribute to the high activity of MTQDs/graphene composite.