Effect of contact interface between TiO2 and g-C3N4 on the photoreactivity of g-C3N4/TiO2 photocatalyst: (001) vs (101) facets of TiO2

In this paper, effect of contact interfaces of high-energy TiO2, (1 0 1) and (0 0 1) facets, with g-C3N4 on the photocatalytic activity of g-C3N4/TiO2 hybrid was studied using TiO2 hollow nanobox (TiO2-HNB) assembly from high-energy TiO2 nanosheets (TiO2-NS) as model. The prepared photocatalyst was characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM), nitrogen sorption, Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance spectroscopy (DRS) and X-ray photoelectron spectrometer (XPS). The photoreactivity of the photocatalyst was evaluated by measure the formation rate of photo-induced hydroxyl radicals ((OH)-O-center dot) using coumarin as a probe molecule and photocatalytic degradation of Brilliant Red X3B (an anionic dye) under UV irradiation (lambda =365 +/- 10 nm). It was found that g-C3N4/TiO2-HNB forms direct Z-scheme photocatalytic system, which shows superior enhancement on the photocatalytic activity of TiO2 than g-C3N4/TiO2-NS. It is by contacting g-C3N4 with (1 0 1) facets, g-C3N4 can efficient remove the photo-generated electrons accumulated on (1 0 1) facets of high-energy TiO2, which results in spatially isolated photo-generated electrons and holes, enhancing the photocatalytic activity. (C) 2014 Elsevier E.V. All rights reserved.