Preparation of superlong TiO2 nanotubes and reduced graphene oxide composite photocatalysts with enhanced photocatalytic performance under visible light irradiation

A novel composite photocatalyst, reduced graphene oxide (rGO) modified superlong TiO2 nanotubes (LTNTs) with length of about 500 nm, has been successfully synthesized by improved hydrothermal process and heating reflux method. The prepared rGO-LTNT catalysts have been characterized and analyzed by transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, powder X-ray diffraction (XRD), photoluminescence spectroscopy (PL) and electron paramagnetic resonance (EPR). The results from these investigations provided a deep insight into the physical structure and chemical composition of the rGO-LTNT nanocomposites and pure LTNT. Furthermore, the photocatalytic activity of rGO-LTNT nanocomposites for degradating methylene blue (MB) solution was evaluated under visible light irradiation. The obtained 1.5% rGO content of rGO-LTNT photocatalyst showed a purification of more than 50% MB in MB solution for an hour, which was about five times higher than that of the pure TNT. The results confirmed that the prepared rGO-LTNT nanocomposite photocatalysts showed excellent co-photocatalytic ability. That's because rGO played a critical role in utilizing solar light and increasing separation of the electron-hole pairs more efficiently, and which greatly accelerated the decomposition of organic pollutants in waste water or air.