Photocatalytic oxidation for removal of gases toluene by TiO ₂ -CeO ₂ nanocomposites under UV light irradiation

Simple sol-gel method has used to synthesize TiO ₂ -CeO ₂ nanocomposites. XRD analysis carried out to determine the phase and structural properties of the synthesized nanocomposites. Thermal and gravimetric stability of the samples were determined by TGA. The optical spectroscopic study revealed that the nanocomposites show the shifting of band edge towards higher wavelength with an increase in the CeO ₂ content in nanocomposites as compared to pure TiO ₂ . Morphology of the synthesized nanocomposites was confirmed by FE-SEM and TEM analysis. Synthesized nanomaterials are in spherical with particle sizes in the range 10–20 nm. The HR-TEM image showed the formation of the heterojunction between CeO ₂ and TiO ₂ NPs and their elemental composition was confirmed by EDS. Surface chemical bonding states and the electronic valence band positions of the elements in nanocomposites were determined by XPS analysis. Photoluminescence study revealed the effect of CeO ₂ concentration on photogenerated electron-hole pairs in TiO ₂ nanoparticles. Photocatalytic activity of synthesized nanomaterials was studied by decomposition of toluene gas with irradiation of UV light. Revealed that nanocomposites with TiO ₂ :CeO ₂ ratio of 3:1 had the highest photocatalytic efficiency as compared to the other nanocomposites and pure TiO ₂ and CeO ₂ nanoparticles. Therefore, the results confirmed that the coupling of TiO ₂ with CeO ₂ absorb the photon energy and generates reactive oxygen species, which are easily transferred to CeO ₂ , causing enhances the separation of the electron-hole pair and an improved the photocatalytic activity of the nanocomposites.