A visible-light-driven composite photocatalyst of TiO2 nanotube arrays and graphene quantum dots

TiO2 nanotube arrays are well-known efficient UV-driven photocatalysts. The incorporation of graphene quantum dots could extend the photo-response of the nanotubes to the visible-light range. Graphene quantum dot-sensitized TiO2 nanotube arrays were synthesized by covalently coupling these two materials. The product was characterized by Fourier-transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and UV–vis absorption spectroscopy. The product exhibited high photocatalytic performance in the photodegradation of methylene blue and enhanced photocurrent under visible light irradiation