Порівняльний аналіз TiO2 кодопованого Gd і Sm, Tm, або Tb, синтезованого одностадійним та двостадійним гідротермальним методом

• Дата: 2025
• Автори: Khalyavka, T.O., Burve, R., Shcherban, N.D., Korzhak, G.V., Yaremov, P.S., Coşkun, E., Grivel, J.-C.
• Формат: Стаття
• Мова: English
• Опубліковано: Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine 2025
• Теми: діоксид титану; рідко-земельні елементи; кодопування; одностадійний і двостадійний гідротермальний синтез; фотокаталіз
• Онлайн доступ: https://www.cpts.com.ua/index.php/cpts/article/view/795
• Назва журналу: Chemistry, Physics and Technology of Surface

The presented work aimed to synthesize anatase-brookite TiO2 co-doped with Gd/Sm, Gd/Tm or Gd/Tb by simple template-free one-step and two-step hydrothermal procedures in aqueous media and to compare the structural, textural and photocatalytic properties of co-doped TiO2 obtained by different techniques to find an effective synthesis approach and to study the impact of co-doping. The materials were characterized using X-ray diffraction (XRD) analysis, Raman spectroscopy, scanning (SEM-EDS) and high-resolution transmission (HRTEM) electron microscopies, UV-Vis diffuse reflectance spectroscopy (DRS), and volumetric nitrogen adsorption method. The XRD, Raman and TEM analyses detected the anatase and brookite phases in the undoped and co-doped TiO2 with crystallite sizes of around 9 and 10-13 nm, respectively. All powders are highly crystallized materials; the crystallinity index of one- and two-step synthesized materials is similar. The mesoporous structure with wide pore size distribution of the powders was confirmed by presence of H1 type hysteresis loops. The two-step co-doped samples have a wider pore size distribution compared with one-step samples and undoped TiO2. It was found that the use of the one-step synthesis procedure contributed to the formation of materials with larger surface area. Besides, these materials show stronger absorption in the visible region, compared with two-step synthesized powders. Co-doped powders showed higher photocatalytic activity in the reactions of hydrogen evolution and Rhodamine B degradation than undoped TiO2 under UV light and in Rhodamine B degradation under visible light, which can be explained by the capability of the rare earth elements to form defects that capture excited electrons, improving charge separation, extending their lifetime, and preventing electron-hole recombination. It is observed that between the one-step and two-step synthesized groups, the powders of the former group were more photocatalytically active, which is related with their larger surface area, and stronger absorption in the visible region. Summarizing the results of the preparation and application of photocatalysts, it can be stated that the use of the more economical one-step synthesis procedure contributes to the formation of more effective photocatalysts.