Novel spindle-shaped nanoporous TiO2 coupled graphitic g-C3N4 nanosheets with enhanced visible-light photocatalytic activity

Highly efficient visible-light-driven heterojunction photocatalysts, spindle-shaped nanoporous TiO2 coupled with graphitic g-C3N4 nanosheets have been synthesized by a facile one-step solvothermal method. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N-2 adsorption-desorption analysis and UV vis diffuse reflectance spectrometry (DRS), proving a successful modification of TiO2 with g-C3N4. The results showed spindle-shaped nanoporous TiO2 microspheres with a uniform diameter of about 200 nm dispersed uniformly on the surface of graphitic g-C3N4 nanosheets. The g-C3N4/TiO2 hybrid materials exhibited higher photocatalytic activity than either pure g-C3N4 or nanoporous TiO2 towards degradation of typical rhodamine B (RhB), methyl blue (MB) and methyl orange (MO) dyes under visible light ( > 420 nm), which can be largely ascribed to the increased light absorption, larger BET surface area and higher efficient separation of photogenerated electron hole pairs due to the formation of heterostructure. In addition, the possible transferred and separated behavior of electron hole pairs and photocatalytic mechanisms on basis of the experimental results are also proposed in detail. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.