Heterojunction of facet coupled g-C3N4/surface-fluorinated TiO2 nanosheets for organic pollutants degradation under visible LED light irradiation

Novel construction of a heterojunction structure by facet coupling of surface-fluorinated TiO2 (F-TiO2) nanosheet onto g-C3N4 nanosheet as a visible light photocatalyst was achieved through a simple hydrothermal method. Facet coupled structure between F-TiO2-{0 0 1} nanosheet and g-C3N4-{0 0 2} nanosheet was evidently investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), Fourier transform infrared (FT-IR) spectroscopy and UV-vis diffuse reflectance spectroscopy (DRS). The g-C3N4/F-TiO2 facet coupled hybrid with remarkably increased interfacial area presented a significantly enhanced photocatalytic performance in degrading methylene blue (MB) under 410 nm LED light irradiation. The obviously reduced electron-hole recombination rate of hybrid was demonstrated from photoluminescence (PL) spectroscopy measurements and the photoelectrochemical evaluation. An optimal g-C3N4 content has been determined to be 30 wt%, corresponding to apparent pseudo-first-order rate constant k(app) of 0.0374 min(-1). It is 4.5 times and 13.9 times more than that of pure F-TiO2 nanosheets and commercial P25 photocatalyst, respectively. (C) 2014 Elsevier B.V. All rights reserved.