Enhanced photocatalytic activity of anatase-TiO2 nanoparticles by fullerene modification: A theoretical and experimental study

A series of fullerene (C-60)-modified anatase TiO2 (a-TiO2) nanocomposites with different weight loadings of C-60 were successfully synthesized by a simple solution phase method. The as-prepared C-60@a-TiO2 nanocomposites were characterized by X-ray diffraction (XRD), Raman spectroscopy, Brunauer-Emmett-Teller (BET), UV-vis diffuse reflectance absorption spectra (DRS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). The photocatalytic degradation of methylene blue (MB) by the neat a-TiO2 and C-60@a-TiO2 nanocomposites was investigated under UV-A light irradiation, demonstrating that C-60 effectively enhances the photocatalytic activity of a-TiO2 nanoparticles with an optimal amount of 2.0 wt%. By combining with the density functional theory (DFT) calculations, we investigated the electronic structures of C-60@a-TiO2 hetero-interfaces to reveal the underlying principle of the C-60 loading on the photocatalytic activity. It was found that the incorporation of C-60 on the a-TiO2 surface not only narrowed the band gap, but also introduced an additional doping state between the valance and conduction band. Therefore, the presence of intermediate electronic state will in turn contribute to the efficient charge separation and enhanced light adsorption for the C-60@a-TiO2 nanocomposites, resulting in an improved photocatalytic performance. (C) 2016 Elsevier B.V. All rights reserved.