g-C3N4/TiO2 hybrid photocatalyst with wide absorption wavelength range and effective photogenerated charge separation

Not only for utilizing both visible and UV light but also for enhancing photogenerated charge separation capability, a hybrid photocatalyst composed of graphite-like carbon nitride (g-C3N4, mainly response to visible light) and TiO2 (response to UV light) was fabricated by a hydrolysis approach. The TEM images of g-C3N4/TiO2 samples displayed that TiO2 nanoparticles dispersed well on the surface of g-C3N4 sheet and the average size of TiO2 particles on g-C3N4 sheet was much smaller than that of TiO2 samples without g-C3N4 sheet, meaning the inhibiting TiO2 aggregation function of g-C3N4 sheet. The UV-Vis diffuse reflectance spectra displayed that the optical absorption range of g-C3N4/TiO2 hybrid was from 300 to 450 nm, including both UV and visible light. The lower intensity of photoluminescence for g-C3N4/TiO2 than those for pristine g-C3N4 and TiO2, indicated that the recombination of photogenerated charge was inhibited effectively. Profiting from the above mentioned advantages, g-C3N4/TiO2 showed good photocatalysis capability. The pseudo-first-order kinetic constant of phenol degradation on g-C3N4/TiO2 was 2.41 and 3.12 times those on pristine g-C3N4 and TiO2, respectively. We also proposed the scheme for electron-hole separation and transport at the light-driven g-C3N4/TiO2 hybrid photocatalyst interface as well as the phenol degradation mechanism under full spectrum and visible light irradiation. (C) 2012 Elsevier B.V. All rights reserved.