Impact of Gd ions from the lattice of TiO2 nanoparticles on the formation of reactive oxygen species during the degradation of RhB under visible light irradiation

Abstract Gd doped TiO 2 nanoparticles with different dopant concentration were prepared by sol-gel method. The crystalline structure of all samples corresponds to the tetragonal anatase phase. Gd 3+ doping inhibit the grain size and increase the micro-strains. The decrease of the nanoparticles size by doping was evidenced by Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). Specific bands of brookite phase appear in Raman spectra. Electron Spin Resonance (ESR) spectroscopy and high resolution transmission electron microscopy (HRTEM) proved the presence of Gd 3+ ions substitutionally incorporated at Ti 4+ sites of TiO 2 lattice. All the samples show photocatalytic activity against RhB and the best performance was obtained using 0.3% Gd-doped TiO 2 nanoparticles. The presence of hydroxyl radical at the solid–liquid interface was evidenced using ESR experiment coupled with spin-trapping technique and their influence on photocatalytic activity of the samples was highlighted. With increasing Gd doping level a little increase of the optical band gap was determined.