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

Abstract

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 450nm, 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.