S 54 Shishmakov, A. B. Concise synthesis of silver-containing titania xerogels / A. B. Shishmakov, Yu. V. Mikushina // Russian Journal of Applied Chemistry. - 2021. - Vol. 94, № 7. - P879-883 Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): XEROGEL -- CALCINATION -- TITANIUM DIOXIDE -- SILVER Аннотация: A concise procedure was developed for the synthesis of silver-containing xerogels Ag(0)/TiO2 [0.23.2 wt % Ag(0)], including the dissolution of AgNO3 in tetrabutoxytitanium, hydrolysis of the solution in acetic acid–water vapors, drying, and calcining the xerogel at 600–800°C. It was found by X-ray diff raction analysis and electron microscopy that the bulk of metallic silver particles (75–90%) in the material calcined at 800°C has a size of 25–45 nm. The fraction of particles (in the form of crystal intergrowths) with a diameter of 95–115 nm rises with an increase in the AgNO3 concentration at the dissolution stage; TiO2 is present in the rutile phase. At a calcination temperature of 600°C, the dominant TiO2 phase (72%) is anatase; in this case the size of silver particles is 5–10 nm. |
Shishmakov, A. B. Few-step synthesis of PdO/TiO2 and Pd/TiO2 xerogels / A. B. Shishmakov, Yu. V. Mikushina, O. V. Koryakova // Inorganic Materials. - 2021. - Vol. 57, № 2. - P164-170 Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): XEROGEL -- TITANIUM DIOXIDE -- PALLADIUM Аннотация: We demonstrate a few-step technique for the synthesis of PdO/TiO2 and Pd/TiO2 (0.1–2.0 wt % Pd) xerogels, which comprises hydrolysis of a palladium nitrate solution in titanium tetrabutoxide in the vapor atmosphere over an aqueous acetic acid solution, drying, and calcination of the material between 800 and 870°C. According to X-ray diffraction and electron microscopy characterization results, after calcination at 800°C the xerogels contained palladium in the form of PdO particles ≤3–5 nm in size. The highly dispersed palladium(II) oxide covered the surface of the rutile crystallites and filled pores in between. Throughout the range of Pd(NO3)2 concentrations studied, the PdO particles were identical in size. In the material calcined at 870°C, palladium had the form of metallic particles ranging in diameter from 55 to 420 nm. Raising the palladium nitrate concentration in titanium tetrabutoxide was shown to increase the average size of the Pd particles. |