Effect of contact interface between TiO2 and g-C3N4 on the photoreactivity of g-C3N4/TiO2 photocatalyst: (0 0 1) vs (1 0 1) facets of TiO2

In this paper, effect of contact interfaces of high-energy TiO 2 , (1   0   1) and (0   0   1) facets, with g-C 3 N 4 on the photocatalytic activity of g-C 3 N 4 /TiO 2 hybrid was studied using TiO 2 hollow nanobox (TiO 2 -HNB) assembly from high-energy TiO 2 nanosheets (TiO 2 -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) using coumarin as a probe molecule and photocatalytic degradation of Brilliant Red X3B (an anionic dye) under UV irradiation ( λ   =   365   ±   10   nm). It was found that g-C 3 N 4 /TiO 2 -HNB forms direct Z-scheme photocatalytic system, which shows superior enhancement on the photocatalytic activity of TiO 2 than g-C 3 N 4 /TiO 2 -NS. It is by contacting g-C 3 N 4 with (1   0   1) facets, g-C 3 N 4 can efficient remove the photo-generated electrons accumulated on (1   0   1) facets of high-energy TiO 2 , which results in spatially isolated photo-generated electrons and holes, enhancing the photocatalytic activity.