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

A series of fullerene (C₆₀)-modified anatase TiO₂ (a-TiO₂) nanocomposites with different weight loadings of C₆₀ were successfully synthesized by a simple solution phase method. The as-prepared C₆₀@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 C₆₀@a-TiO₂ nanocomposites was investigated under UV-A light irradiation, demonstrating that C₆₀ 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 C₆₀@a-TiO₂ hetero-interfaces to reveal the underlying principle of the C₆₀ loading on the photocatalytic activity. It was found that the incorporation of C₆₀ 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 C₆₀@a-TiO₂ nanocomposites, resulting in an improved photocatalytic performance.