Investigation of oxygen vacancies in Ce coupled TiO2 nanocomposites by Raman and PL spectra

J Dhanalakshmi, S Iyyapushpam, S T Nishanthi, M Malligavathy and D Pathinettam Padiyan

Abstract

CeO₂–TiO₂ nanocomposites with different Ce weight percentages (2, 4, 6 and 8%) were synthesized by sol-gel method. The influence of cerium inclusion on the structural, morphological, optical properties and elemental composition has been analyzed via XRD, BET surface area analysis, UV-DRS, HR-SEM, EDAX, TEM, Raman and photoluminescence spectra. The structural study showed that all the CeO₂–TiO₂nanocomposites crystallized in tetragonal structure with anatase phase. Morphological study revealed that the nanocomposites are in spherical shape with size between 13–15 nm. Raman and PL spectra confirmed the presence and influence of oxygen vacancy defects. The adsorption ability of the CeO₂–TiO₂ nanocomposites was investigated for congo red dye under dark condition. CeO₂–TiO₂ nanocomposites have enhanced adsorptive performance in comparison with bare TiO₂ nanoparticles. The enhanced adsorptive activity of CeO₂–TiO₂nanocomposites is due to the higher surface area of the nanocomposites and oxygen vacancies present in the surface of the nanocomposites. The pseudo second order kinetic equation fits well with higher correlation coefficient compared to the pseudo first order in explaining the reaction kinetics