Solid solutions Zn
1−x
Mn
x
O (0 ≤ x ≤ 0.05) and composite materials Zn
1−x
Mn
x
O:Mn
3
O
4
have been synthesized by the precursor technology using mixed formate glycolate Zn
1−x
Mn
x
(HCOO)(OCH
2
CH
...2
O)
1/2
, glycolate Zn
1−x
Mn
x
(OCH
2
CH
2
O) and glycerolate Zn
1−x
Mn
x
(OCH
2
OCHCH
2
OH) (0 ≤ x ≤ 0.2) as precursors. The XRD patterns of all the samples confirmed the formation of ZnO wurtzite-type structure. They exhibited a high photocatalytic activity both under ultraviolet and visible irradiation. According to the voltammetry data, all the examined compounds contain Mn
3+
ions in the surface layer, whose concentration increases upon transition to composites.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Solid solutions Zn1−xCuxO and/or hybrid materials Zn1−xCuxO/CuxO of the “core-shell” type were obtained by one-step thermolysis of Zn1−хCux(HCOO)(OCH2CH2O)1/2 complexes. Precursors the ...Zn1−хCux(HCOO)(OCH2CH2O)1/2 complexes were synthesized under solvothermal method from the corresponding formates and ethylene glycol. It was established that copper in these materials is a promoter of the photoactivity and morphology of aggregates. Zn1−xCuxO solid solutions (0 < x < 1) have 1D-morphology of aggregates, Zn1−xCuxO/CuxO hybrid materials are spherical. According to TEM, XPS, optical spectroscopy and voltammetry data, Cu+ prevails in the solid solution samples and its concentration increases with transition to hybrid materials. It was shown that solid solutions with tubular particle morphology exhibit the maximum photoactivity of As3+ in UV and blue light. The expansion of the spectral range of Zn1−xCuxO irradiation to the visible region is explained by the formation of acceptor levels (Cu2+ + e− → Cu+/VO+ + e− → VO) in the band gap of ZnO, which increases the efficiency of separation of photogenerated electron-hole pairs. The presence of Cu+ in the material intensify photoactivity due to the formation of an overactive oxygen radical O2−.
•Novel one step synthesis of Zn1−xCuxO/CuxO by thermolysis of Zn1−хCux(HCOO)(OCH2CH2O)1/2 was used•Cu concent determines the formation of solid solutions Zn1−xCuxO or core-shell composite Zn1−xCuxO/CuxO•The synthesis provides stabilization of Cu (I) and Cu (II) simultaneously.•1–D Zn1−xCuxO (x = 0.025 and 0.05) showed improved performance photoactivity in As (III) oxidation on visible light•Presence of Cu(I) в Zn1−xCuxO/CuxO intensify photoactivity through the formation of O2−
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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Current–voltage characteristics of nanostructured vanadium oxide bronze β-NaV6O15 obtained from oxalate solutions by ultrasonic spray pyrolysis (USP) under various conditions were ...studied. The conditions of USP synthesis significantly affected the particle morphology, specific surface area, defect structure and oxidizing ability of the compound.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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Functional materials based on highly dispersed amorphous silica and cobalt compounds have been obtained by solvothermal and mechanochemical methods. The formation of silicate ...Co3(Si2O5)2(OH)2 under hydrothermal conditions has been established. This composition, in comparison with mechano-mixes, provides better photoactivity in the hydroquinone decomposition reaction under ultraviolet irradiation, herewith maintaining the surface characteristics of amorphous SiO2.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Various methods have been developed to reduce the band gap of TiO2 via combining TiO2 with quantum dots (QDs). However, the attainment of high activity and stability of hybrid QDs/TiO2 is still a ...significant challenge since the poor interface contact between QDs and TiO2. This drawback could be tackled to some extent through optimisation of the preparation technology. The present study suggests a simple hydrolysis route to in situ TiO2 doping by pre-synthesized CdS QDs, which play a role of crystal seeds, pre-planted in liquid titanium alkoxide, for the TiO2 crystallization process. The comprehensive investigation of the CdS/TiO2 composite is carried out by X-ray diffraction, UV–Visible spectroscopy, scanning electron microscopy, photocatalytic activity measurements in the photo oxidation of cyclic aromatic organic compounds. The stability of model TiO2-shell structures on CdS seeds is assessed by means of molecular dynamics simulations. Both experimental and theoretical results confirm the mutual impact of CdS QDs and TiO2 on their crystallinity. The presence of CdS QDs in the solution provokes the formation of amorphous TiO2 clusters, while the high TiO2 content leads to amorphization of CdS QDs. The CdS/TiO2 composite particles consisting of CdS amorphous core and TiO2 amorphous shell demonstrate the highest photocatalytic activity.
•In situ TiO2 doping by pre-synthesized CdS QDs was suggested.•CdS QDs behaved as crystal seeds while in situ hydrolysis of titanium alkoxide.•Mutual impact of CdS and TiO2 on crystallinity in CdS/TiO2 particles was revealed.•Amorphous CdS/TiO2 composite demonstrated the highest photocatalytic activity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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The Zn1–xCuxO (0 <x ≤ 0.1) solid solutions and Zn1–xCuxO: CuO composite materials have been synthesized by a precursor technology using Zn1–xCux(HCOO)2·2H2O (0 <x ≤ 0.2) mixed ...formates as precursors, and their structural, optical and photocatalytic characteristics have been ascertained.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The effect of different factors, such as pH of the medium (1.5 < pH < 4.0; 1 × 10–4 mol·L–1 < SO42– < 1 × 10–1 mol·L–1), the concentration of extracting agent, temperature and the type of the ...solvent, on the extraction of vanadium(V) by trioctylamine was studied. It was shown that the extraction of vanadium(V) by trioctylamine at 25 ± 0.5 °C takes place in the pH range 2.0–3.5 and the extracting complex contains decavanadate anion H2V10O284– and four molecules of the extracting agent. This allows the reaction of vanadium(V) extraction by trioctylamine to be described by the following equation: 2(R3NH)2SO4 + H2V10O284– → (R3NH)4H2V10O28 + 2SO4. The effect of the length of the alkyl chain of alcohol (propyl, butyl, isododecyl alcohol) on the homogeneity of the system VV‐TOA‐toluene‐alcohol was investigated. It was established that the solubility of the extracting complexes of vanadium(V) with trioctylamine can be increased by using isododecyl alcohol C12H25OH as a modifying agent. It was shown that under optimal conditions in the presence of isododecyl alcohol at temperatures above 25 °C in the pH interval 2.0–3.5 trioctylamine extracts vanadium(V) with a high distribution coefficient (lg DVV > 2).
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
