TiO2/carbon nanotube hybrid nanostructures: Solvothermal synthesis and their visible light photocatalytic activity

MWCNT/TiO2 hybrid nanostructures were prepared via solvothermal synthesis and sol–gel method with benzyl alcohol as a surfactant. As-prepared hybrid materials were characterized by X-ray diffraction, transmission electron microscopy, UV–vis diffuse reflectance spectra and X-ray photoelectron spectroscopy. The results showed that MWCNTs were uniformly decorated with anatase nanocrystals in solvothermal condition, but MWCNTs were embedded in a majority of TiO2 nanoparticles by sol–gel method. When the weight ratio of MWCNTs to TiO2 was 20%, MWCNT/TiO2 hybrid nanostructures prepared by solvothermal synthesis exhibited higher visible-light-driven photocatalytic activity than that prepared by sol–gel method. Post-annealing of MWCNT/TiO2 nanostructures at 400 °C resulted in the formation of the carbonaceous Ti–C bonds on the interface between TiO2 and MWCNTs, which enhanced the photoabsorbance of the hybrid materials in the visible light region and improved the visible-light degradation efficiency of methylene blue.