Nanocomposite photocatalysts of carbon nitride loaded on TiO₂ and graphene oxide loaded on TiO₂ different mass ratios were prepared by a hydrothermal treatment method and characterized using X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), UV-Vis diffuse reflectance spectroscopy (DRS) and Transmission Electron Spectroscopy (TEM). UV-Vis diffuse spectrum showed that the both nanocomposits exhibited absorption in the visible light range. The kinetics of the phenolic degradation using the as-prepared nanocomposite photocatalysts compared to the bare TiO₂ nanoparticles was tested using Xenon lamps (mainly a visible light source) as a photoexcitation source in presence and absence of H₂O₂ and/or O₃. For example, The photodegradation of phenol was evaluated using UV spectrophotometer and total organic carbon (TOC). It was revealed that the photocatalytic activity of the CNTi composites significantly higher than TiO₂ nanoparticles. Furthermore, 0.1CNTi composite showed the best phenol degradation when H₂O₂ and O₃ were simultaneously used in which the degradation percentage of phenol was more than 90% within 30 min