Mechanochemical, Sonochemical and Hydrothermal Activation of Niobium Pentoxide and its Catalytic Properties

Modification of niobium pentoxide with different dispersity via mechanochemical, ultrasound, hydrothermal and microwave treatments (MChT, UST, HTT, and MWT, respectively) has been studied. All types of treatment do not change of phase composition but leads to improvement (at HTT and MWT) or, on contrary, breaking of crystal structure (at MChT and UST) and variation of crystallite size and specific surface area. UV-Vis measurements display increase of absorption in visible region. As a result, modified samples show higher photocatalytic activity at degradation of rhodamine B under visible irradiation. Similarly, initial and modified Nb2O5 samples are catalysts for mechanochtmical and sonochemical destruction of the same dye. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3515

Synthesis and Photocatalytic Properties of Silver Niobate

The interaction between silver nitrate and niobium pentoxide has been studied under conventional thermal treatment (TT) as well as mechanochemical and sonochemical treatment (MChT and UST, respec-tively). The products of reaction have been investigated using XRD, DTA-TG, Raman spectroscopy, adsorp-tion of nitrogen. MChT and UST promote lowering the temperature of silver niobate (SN) formation. The formed SN possesses higher specific surface area and photocatalytic activity. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3527

Mechanochemical Modification of V-Mo-Zr Oxide Compositions

The influence of mechanochemical treatment by high-energy ball milling in two media (water and ethanol) of different $V_{2}O_{5}$/$MoO_{3}$/$ZrO_{2}$ compositions on its structure modification and photocatalytic properties is considered. Milling process in both media leads to final products $Zr(V_{2}O_{7})$ and $Mo_{4}V_{6}O_{25}$. Their subsequent thermal treatment provides to formation of $Zr(MoO_{4})_{2}$ and $V_{2}MoO_{8}$ composition. They show the photocatalytic activity in the dyes degradation process in aqueous solution

The influence of mechanochemical activation on the Zn–Ce–O composition properties

The influence of mechanochemical treatment in air at different conditions (treatment time, ball-to-powder ratio, diameter of the balls) on oxide zinc–cerium composition ZnO–CeO 2  = 50:50 (molar ratio) properties was studied. The decrease in the particle size of oxides (CeO 2 – from 57 up to 18 nm, ZnO – from 174 up to 40 nm) and formation of Zn–Ce–O nanocomposite was shown by X-ray diffraction and transmission electron microscopy methods. The optimal treatment conditions (diameter of the balls 5–10 mm, ball-to-powder ratio = 15, time treatment 2–4 hours) were established. An increase in the specific surface area (up to three times) and pores volume due to the formation of mesopores with two dimensions (2.1 and 30 nm) at these conditions was shown by Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods. The increase in the photocatalytic activity of the dye safranin T decomposition due to the formation of Zn–Ce–O nanocomposite was established

Effect of ultrasonic treatment on formation of nanodimensional structures in ZnO-MoO_{3} system

The effect of ultrasonic treatment on transformations in the ZnO-MoO_{3} oxide system with atomic ratios Zn/Mo = 15 : 85, 25 : 75, 50 : 50, and 75 : 25 was investigated. It was shown that sonochemical activation leads to phase transformations in molybdenum oxide, its reduction with the formation of molybdenum suboxides (Mo_{8}O_{23}, Mo_{4}O_{11}), and chemical reaction between the initial oxides with the formation of zinc molybdate (á-ZnMoO_{4}). Nanoparticles with increased specific surface area and pore size compared with the initial compositions are formed. Similarities were found between the sonochemical and mechanical activation of composites of the system