In English

Abstract

The aim of our work was to prepare nanoscale composites based on TiO 2 and carbon photocatalytically active under UV and visible irradiation in the destruction of safranin T. The samples were characterized by XRD, BET, SEM, UV-Vis and IR spectroscopy. X-ray analysis revealed photocatalytically active phase of anatase in all the composites. The powders consist of roundish agglomerates, crystallite size in agglomerates is 15 nm. Analysis of nitrogen sorption–desorption isotherms for the samples show the presence of a hysteresis loop which is the evidence for mesoporous structure. Vibrational spectra of the composites reveal the following bands: near 700 cm −1 corresponding to the Ti–O stretching vibration; around 3407 cm –1 attributed to the surface-adsorbed H 2 O; at 1628 cm –1 which is referred to deformational vibrations in adsorbed water, and around 1300–1500 cm –1 corresponding to carbon–oxygen bonds. Absorption spectra of nanocomposites show a bathochromic shift as compared with those of TiO 2 . Modification of TiO 2 with carbon leads to band gap narrowing of composites, as well as to emerging of additional energy levels in the band gap of TiO 2 with energies of 3.12–3.14 eV under valence band; that leads to sensitizing of C/TiO 2 composites to visible irradiation. Nanocomposites show higher photocatalytic activity compared to pure TiO 2 . It may be connected with the participation of carbon in the inhibition of electron–hole recombination, prolongation of charge lifetime, increasing of efficiency of interfacial charge separation from TiO 2 to carbon and formation of doping electronic states inside the TiO 2 band gap.