Preparation, characterization, and application in water purification of g-C3N4/I-TiO2 composite photocatalysts

Novel g-C 3 N 4 /I-TiO 2 composite photocatalytic systems, having various wt/wt% of g-C 3 N 4 : 0, 30, 40, and 50, were successfully designed and were prepared hydrothermally. The eventually prepared specimens were characterized spectroscopically by Fourier transform infrared (FT-IR), solid-state ultraviolet-visible (UV-Vis) absorbance, X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Their Brunauer-Emmett-Teller (BET) specific surface areas were estimated by nitrogen physisorption, while their morphology was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The photocatalytic activities of g-C 3 N 4 /I-TiO 2 composites were evaluated by the oxidative degradation of methylene blue (MB) via the irradiation of visible-light having wavelength greater than 420 nm. Tetragonal anatase phase of TiO 2 and graphitic carbon nitride (g-C 3 N 4 ) were detected for the prepared composite catalysts. The composite photocatalyst samples were found to have aggregate semi-spherical particles, as revealed by scanning and transmission electron microscopy (SEM and TEM) investigation. g-C 3 N 4 /I-TiO 2 composite photoactive component was incorporated in varying amounts of g-C 3 N 4 , and the resulting composites were proved to have improved photoactivity over the composite containing only I-TiO 2 . Under optimal experimental condition, the 40wt% g-CN/I-TiO 2 composite photocatalyst exhibited the highest photocatalytic activity. g-C 3 N 4 has the ability to absorb the incident photons, resulting in exciting the electrons between the frontier orbitals. These excited electrons, in turn, move to I-TiO 2 via the interfacial border, hindering the recombination of the photo-induced electrons and holes, and thus, improving the performance of the photpcatalyst. This work presented novel g-C 3 N 4 /I-TiO 2 composite photocatalyst that can be used in waste water remediation. g-C 3 N 4 /I-TiO 2 composite is a material of particular interest due to its chemical and photo-corrosion stability.