Synthesis of g-C3N4/TiO2 heterojunction composites with enhanced solar light photocatalytic activity

Gündoğmuş, Peli
The solar light sensitive g-C3N4/TiO2 composites containing various amounts of graphitic carbon nitride (g-C3N4) and titania (TiO2) were prepared by the hydrothermal and sol-gel processes for photocatalytic applications. Hydrothermally derived g-C3N4/TiO2 composites were subjected to regulated heat treatments at temperatures ranging from 350 to 500 oC for 1 h to improve their photocatalytic efficiency. Particle size, crystal structure, morphology, and optical properties of the g-C3N4/TiO2 nanocomposites were investigated and were compared with those of the pristine TiO2 and g-C3N4 powders using particle size analyzer, X-ray diffractometer, Field emission scanning electron microscope, Fourier transform infrared spectroscopy, Raman spectroscopy, diffuse reflectance spectroscopy (DRS) and UV-Vis spectrophotometer. Photocatalytic activity of all powders was assessed by the Methylene Blue (MB) degradation test under solar light illumination. The results revealed that g-C3N4/TiO2 composites exhibited better photocatalytic activity for the degradation of MB than both pristine TiO2 and g-C3N4. Hydrothermally derived and sol-gel derived g-C3N4/TiO2 composites showed 100% and 87.05%, respectively photocatalytic efficiency under 180 min solar light illumination. The enhancement in photocatalytic activity was related to the generation of reactive oxidation species induced by photogenerated electrons and reduced recombination rate of the electron-hole pairs.
Citation Formats
P. Gündoğmuş, “Synthesis of g-C3N4/TiO2 heterojunction composites with enhanced solar light photocatalytic activity,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Metallurgical and Materials Engineering., Middle East Technical University, 2020.