TiO₂/TeO₂ powders were obtained by an aqueous sol-gel method. Telluric acid (H₆TeO₆) and titanium butoxide were used as precursors. The as-prepared gel was step-wisely heated in the temperature range 200–700 °C and subsequently characterized by XRD, IR, and UV-Vis analysis and SEM. Mixtures containing TiO₂ (anatase), α-TeO₂ (paratellurite), and TiTe₃O₈ were established by XRD as final products, depending on heating temperature. The thermal stability of the obtained gels in the temperature range 100–400 °C was investigated. It was found by IR spectroscopy that the samples heated up to 300–400 °C consist mainly of an organic–inorganic amorphous phase which is transformed into an inorganic one above these temperatures. The microstructure of the gels was verified by scanning electron microscopy (SEM). The photocatalytic degradation of the synthesized nanopowders toward Malachite green organic dye (MG) was examined in order to evaluate the potential applications for environmental remediation. The prepared TiO₂/TeO₂ samples showed up to 60% decoloration efficiency after 120 min exposure to UV-light. The composition exhibited good antimicrobial activity against E. coli K12. The properties of the obtained material were investigated by the reactions of complete catalytic oxidation of different alkanes and toluene, and it could be suggested that TiO₂/TeO₂ powders are promising material for use as an active phase in environmental catalysts.

The current study aims to synthesize and analyze both pure and La-doped TiO₂, and evaluate the photocatalytic and antibacterial activity of as-prepared samples. Doped and undoped samples were prepared by the non-hydrolytic sol–gel method from titanium(IV) chloride, benzyl alcohol, and lanthanum(III) nitrate followed by thermal treatment. Lanthanum content in synthesized samples was 0.4, 1, and 5 mol%. The resulting nanopowders’ structure and morphology were described using XRD, IR, and UV–Vis analysis. The average particle sizes of pure and doped TiO₂ were about 6–15 nm and anatase was found to be a dominant crystalline phase in the samples. It was observed that particle sizes decreased on increasing La content. The photocatalytic activity of the pure and La-doped sol–gel powders was estimated in the decomposition of paracetamol in distilled water using ultraviolet light illumination. Doping with lanthanum ions has been shown to increase the photocatalytic properties on the degradation of paracetamol. Furthermore, the annealed catalysts (pure and La³⁺ doped) showed increased photocatalytic activity and degradation of the analgesic in comparison with non-annealed materials. In both cases, the highest photocatalytic efficiency is observed at the optimal La³⁺ (1 mol%) concentration. The antimicrobial activity of 1 mol% La/TiO₂ was tested against a reference strain E. coli in the presence of ultraviolet light and in dark conditions. The number of viable bacterial cells was determined by a spread plate method, and kill curves were performed. The results showed that photoactivated 1 mol% La/TiO₂ exhibited a strong bactericidal effect, and in concentration, 1 mg/mL efficiently killed bacteria at an initial cell density of about 10⁵ colony forming units in 1 mL within 15 min.

The present study is a continuation of our previous investigations on the ZnO-TiO₂ system. By applying different sol-gel methods we proved that the type of precursor and the order of adding the components influence the microstructure of the final product. This study focuses on the combustion sol-gel synthesis and photocatalytic properties of nanosized (∼7-20 nm) ZnO-TiO₂ powders. The photocatalytic tests were performed toward two model organic dyes, Malachite Green and Reactive Black 5, in the UV and Vis region. For synthesis of ZnO/TiO₂ powders, different precursors such as Zn(NO₃)₂·6H₂O, Zn(CH₃COO)₂·2H₂O, Ti(OC₂H₅)₄ and Ti(OC₄H₉)₄ were used. During the combustion process various phases (ZnO, TiO₂ — anatase and rutile, ZnTiO₃) were obtained. The structure and morphology of the resulting particles were characterized by XRD and SEM analysis. All samples exhibited a good photocatalytic activity in both UV and Vis regions.

TiO₂ nanopowders modified by Nd and Sm were prepared using the sol-gel technique. It was found by XRD analysis that the samples containing Sm are amorphous up to 300 °C, while those with Nd preserve a mixed organic-inorganic amorphous structure at higher temperatures (400 °C). The TiO₂ (rutile) was not detected up to 700 °C in the presence of both modified oxides. TiO₂ (anatase) crystals found at about 400 °C in the Sm-modified sample exhibited an average crystallite size of about 25–30 nm, while doping with Nd resulted in particles of a lower size—5–10 nm. It was established by DTA that organic decomposition is accompanied by significant weight loss occurring in the temperature range 240–350 °C. Photocatalytic tests showed that the samples heated at 500 °C possess photocatalytic activity under UV irradiation toward Malachite green organic dye. Selected compositions exhibited good antimicrobial activity against E. coli K12 and B. subtilis.