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Titanium dioxide (anatase) powders mechanochemically modified with carbon and/or thiourea were obtained. X-ray powder diffraction, scanning electron microscopy with an integrated system for electron microprobe analysis, transmission electron microscopy, Brunauer–Emmett–Teller surface area analysis, X-ray photoelectron spectroscopy, infrared and ultraviolet–visible spectroscopies were applied for the powders characterization. Mechanochemical modification with thiourea and/or carbon with carbon and/or thiourea led to a decrease of the particle size from 21 to 13 nm and formation of oblong rice-like particles. The presence of a hysteresis loop in the nitrogen ad(de)sorption isotherms for the synthesized samples proved their mesoporous structure. The features of the XPS spectra in all samples can be attributed to the fine-structure peculiarities associated with titanium, oxygen, and carbon atoms and, in the case of modification with thiourea, additionally, to sulfur and nitrogen. Photocatalytic activity of the samples was investigated in the photodestruction of Safranine T and Rifampicinum. The modified samples showed higher photocatalytic activity in both reactions compared to unmodified anatase under UV irradiation and demonstrated activity under visible light. The reusability of the powders was investigated. [ABSTRACT FROM AUTHOR]

Nanoscale composite materials based on cerium, barium titanate and titanium dioxide were synthesized by thermal hydrolysis. The obtained individual TiO2, BaTiO3 and as-synthesized Ce/xBaTiO3/TiO2 semiconductive nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive spectrometry, transmission electron microscopy, nitrogen adsorption–desorption, UV–vis diffuse reflectance spectroscopy, and Fourier transform infrared spectroscopy. The structural investigations revealed that all prepared powders were nanocrystalline with an average crystallite size within the range of 5–17 nm. Analysis of nitrogen adsorption–desorption isotherms for the synthesized nanocomposites showed the presence of a hysteresis loop, which is evidence for the mesoporous structure of the powders. The photocatalytic degradation of the model pollutants (Safranine T and Rhodamine B) was carried out under UV irradiation. Ce/xBaTiO3/TiO2 nanocomposites showed higher photocatalytic activity compared to pure TiO2 and BaTiO3 as well as BaTiO3/TiO2. An increase of the amount of BaTiO3 in Ce/xBaTiO3/TiO2 samples by more than 12% reduces the photocatalytic activity of nanocomposites while doping of BaTiO3/TiO2 samples with cerium increases their photoactivity. [ABSTRACT FROM AUTHOR]