Enhanced Photocatalytic Activity and Electron Transfer Mechanisms of Graphene/TiO2 with Exposed {001} Facets

Abstract

We present a simple and feasible strategy to synthesize the novel anatase TiO 2 /graphene composites with exposed TiO 2 {001} high-energy facets by the hydrofluoric acid and methanol joint assisted solvothermal reactions. During the synthesis process, graphene was uniformly covered with a large number of anatase TiO 2 nanoparticles (20–25 nm), exposing the {001} facets. The X-ray photoelectron spectroscopy and X-ray absorption measurements show the presence of electron transfer between TiO 2 and graphene. Furthermore, transient photovoltage spectra of the composite also exhibits prolonged mean lifetime of electron–hole pairs compared with pure TiO 2 . The electron transfer between Ti and C will greatly retard the recombination of photoinduced charge carriers and prolong electron lifetime, which contribute to the enhancement of photocatalytic performance. During the photocatalysis measurement, the TiO 2 /graphene composites have high photocatalytic activity compared with the P25 under UV light, likely due to the effective separation of photoinduced charge and exposure of high reactive {001} facets.