The Influence of La Doping on Structural, Optical, and Photocatalytic Properties of TiO2 in Dyes Destruction and Hydrogen Evolution

The effect of La on the structural and optical properties of titanium dioxide aiming to evaluate Safranine T photodestruction (decolorization) and H2 evolution over pure and La-doped TiO2 under UV irradiation was studied. The TiO2 samples with different lanthanum contents were synthesized by the sol–gel method. The samples were analyzed using SEM-EDS microscopy, transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflection spectra (DRUV), room temperature FT-IR spectroscopy, and BET method. It was established that the content of rutile in La/TiO2 composites increases twice compared to pure TiO2. Doping with La leads to a decrease in the anatase crystallite sizes from 10 to 8 nm and rutile crystallite sizes from 7 to 5 nm. Analysis of nitrogen adsorption–desorption isotherms for the synthesized nanocomposites showed the presence of a hysteresis loop, which is the evidence for the mesoporous structure of the powders. The specific surface area of La/TiO2 composites is increased by two times compared to pure TiO2. The absorption edge of La/TiO2 samples is shifted to a shorter wavelength (blue shift) compared to pure TiO2. It was found that La/TiO2 nanocomposites exhibit higher photocatalytic activity than pure TiO2 in the investigated reactions.