109 research outputs found
Π‘ΠΈΠ½ΡΠ΅Π· ΠΈ ΡΠ²ΠΎΠΉΡΡΠ²Π° ΡΠΈΠ»ΠΈΠΊΠ°ΡΠΎΠ² Π²ΠΈΡΠΌΡΡΠ°, ΠΏΡΠΈΠ³ΠΎΡΠΎΠ²Π»Π΅Π½Π½ΡΡ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ ΠΌΠ΅Ρ Π°Π½ΠΈΡΠ΅ΡΠΊΠΎΠΉ Π°ΠΊΡΠΈΠ²Π°ΡΠΈΠΈ
Π Π½Π°ΡΡΠΎΡΡΠ΅ΠΉ ΡΠ°Π±ΠΎΡΠ΅ Π±ΡΠ»ΠΈ ΡΠΈΠ½ΡΠ΅Π·ΠΈΡΠΎΠ²Π°Π½Ρ ΡΠ΅ΡΠΈΠΈ ΡΠΈΠ»ΠΈΠΊΠ°ΡΠΎΠ² Π²ΠΈΡΠΌΡΡΠ° ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌΠΌΠ΅Ρ
Π°Π½ΠΈΡΠ΅ΡΠΊΠΎΠΉ Π°ΠΊΡΠΈΠ²Π°ΡΠΈΠΈ, Π° ΡΠ°ΠΊΠΆΠ΅ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½Ρ ΠΈΡ
ΡΠ²ΠΎΠΉΡΡΠ²Π° ΡΠ°ΠΊΠΈΠΌΠΈ ΠΌΠ΅ΡΠΎΠ΄Π°ΠΌΠΈ, ΠΊΠ°ΠΊ Π’Π-ΠΠ‘Π Π°Π½Π°Π»ΠΈΠ· ΠΈ Π Π€Π-ΡΠΏΠ΅ΠΊΡΡΠΎΡΠΊΠΎΠΏΠΈΡ. Π£ΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΎ, ΡΡΠΎ Π΄Π»Ρ ΡΠ΅ΡΠΈΠΈ, ΠΏΡΠΈΠ³ΠΎΡΠΎΠ²Π»Π΅Π½Π½ΠΎΠΉ Ρ ΡΠΎΠΎΡΠ½ΠΎΡΠ΅Π½ΠΈΠ΅ΠΌ ΡΠ΅Π°Π³Π΅Π½ΡΠΎΠ² Bi:Si = 2:1 ΠΏΠΎΡΠ»Π΅ 800 Β°Π‘ Π½Π°ΡΡΡΠΏΠ°Π΅Ρ ΠΏΠ»Π°Π²Π»Π΅Π½ΠΈΠ΅, ΡΠΎΠ³Π΄Π° ΠΊΠ°ΠΊ Π΄Π»Ρ ΡΠ΅ΡΠΈΠΈ Ρ ΡΠΊΠ²ΠΈΠ°ΡΠΎΠΌΠ½ΡΠΌ ΡΠΎΠΎΡΠ½ΠΎΡΠ΅Π½ΠΈΠ΅ΠΌ Bi ΠΈ Si Π² ΠΈΡΡ
ΠΎΠ΄Π½ΡΡ
ΡΠ΅Π°Π³Π΅Π½ΡΠ°Ρ
ΠΏΠ»Π°Π²Π»Π΅Π½ΠΈΡ Π² ΡΡΠΎΠΌ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ½ΠΎΠΌ ΠΈΠ½ΡΠ΅ΡΠ²Π°Π»Π΅ Π½Π΅ Π½Π°Π±Π»ΡΠ΄Π°Π΅ΡΡΡ. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ ΠΏΡΠΈ ΡΠ²Π΅Π»ΠΈΡΠ΅Π½ΠΈΠΈ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΡ ΠΏΡΠΎΠΊΠ°Π»ΠΈΠ²Π°Π½ΠΈΡ Ρ 500ΛΠ‘ Π΄ΠΎ 700 Β°Π‘ ΡΠ°Π·Π° ΠΌΠ΅ΡΠ°ΡΠΈΠ»ΠΈΠΊΠ°ΡΠ° Π²ΠΈΡΠΌΡΡΠ° (Bi2SiO5) ΠΏΠΎΠ»Π½ΠΎΡΡΡΡ ΠΏΠ΅ΡΠ΅Ρ
ΠΎΠ΄ΠΈΡ Π² ΠΎΡΡΠΎΡΠΈΠ»ΠΈΠΊΠ°Ρ Π²ΠΈΡΠΌΡΡΠ° (Bi4Si3O12), Π° Π΄ΠΎΠ»Ρ ΡΠ°Π·Ρ ΡΠΈΠ»Π»Π΅Π½ΠΈΡΠ° (Bi12SiO20) ΡΠ²Π΅Π»ΠΈΡΠΈΠ²Π°Π΅ΡΡΡ ΠΏΡΠΈ ΡΠ²Π΅Π»ΠΈΡΠ΅Π½ΠΈΠΈ ΡΠΎΠΎΡΠ½ΠΎΡΠ΅Π½ΠΈΡ Bi:Si
Bismuth silicate composite materials prepared via gel process: phases formation, electrochemistry and photocatalytic performance
Synthesis and photocatalytic properties of materials based on bismuth silicates
The influence of the preparation technique of bismuth silicate-based catalysts on their formation, phase composition, absorption characteristics, and photocatalytic properties is investigated. Samples the with initial ratio of Bi: Si = 2: 1 are prepared via the hydrothermal method with varied temperature conditions in the hydrothermal aging and calcination stages. The synthesized catalysts demonstrate photocatalytic activity in the decomposition of the methanol equilibrium vapor and visible light-induced decolorization of a methylene blue (MB) aqueous solution
Catalysis: from science to industry : proceedings of VII International scientific school-conference for young scientists, October 11-15, 2022
The collection is devoted to important and perspective directions of modern catalysis: fundamentals of catalyst preparation and catalytic processes, promising catalytic processes and industrial implementation of catalytic processes
Observation of persistent centrosymmetricity in the hexagonal manganite family
The controversy regarding the ferroelectric behavior of hexagonal InMnO
is resolved by using a combination of x-ray diffraction (XRD), piezoresponse
force microscopy (PFM), second harmonic generation (SHG), and density
functional theory (DFT). While XRD data show a symmetry-lowering unit-cell
tripling, which is also found in the multiferroic hexagonal manganites of
symmetry, PFM and SHG do not detect ferroelectricity at ambient or low
temperature, in striking contrast to the behavior in the multiferroic
counterparts. We propose instead a centrosymmetric phase as the
ground state structure. Our DFT calculations reveal that the relative energy of
the ferroelectric and nonferroelectric structures is determined by a
competition between electrostatics and oxygen--site covalency, with an
absence of covalency favoring the ferroelectric phase.Comment: 8 pages, 9 figure
Continuous metal-insulator transition of the antiferromagnetic perovskite NaOsO3
Newly synthesized perovskite NaOsO3 shows Curie-Weiss metallic nature at high
temperature and suddenly goes into an antiferromagnetically insulating state at
410 K on cooling. Electronic specific heat at the low temperature limit is
absent, indicating that the band gap fully opens. In situ observation in
electron microscopy undetected any lattice anomalies in the vicinity of the
transition temperature. It is most likely that the antiferromagnetic
correlation plays an essential role of the gap opening.Comment: 13 pages, 5 figures, PHYS. REV. B 80, 161104(R),(2009
Investigating the influence of silver state on electronic properties of Ag/Ag2O/TiO2 heterojunctions prepared by photodeposition
Two series of Ag-TiO2 photocatalysts were prepared with the use of photodeposition method with variation of the irradiation time and precursor concentration. The obtained photocatalysts were studied by XRD, Raman spectroscopy, HR TEM, UVβvis spectroscopy, and low-temperature N2 adsorption/desorption method. It has been consequently found that the optical properties of the resulting catalysts differ significantly: the positions of surface plasmon resonance peaks red-shifted with the increase in precursor concentration. At the same time, optical absorption of the samples increases with both precursor concentration and irradiation time. Photocatalytic activity for the obtained catalysts was evaluated in decolorization of Rhodamine B with the use of Xe arc lamp (250 W) with and without Ξ» >420 nm light filter. Radical trap experiments have shown that the amount of both superoxide anions and hydroxyl radicals increased in full spectrum of the lamp, with the latter being absent in the reaction mixture during visible light photocatalysis. Comparison of different Ag-TiO2 catalysts has also been made, with 1-Ag-90 min sample being the most active in full spectrum, and 3-Ag-90 min demonstrating the highest conversion in visible light attributed to the increased generation of superoxide species on the surface of Ag clusters. Controversially, 1-Ag-45 min sample showed the lowest activity in full spectrum being surpassed even by unmodified TiO2, but reached the highest rate constant value in visible light. This effect can be related to advanced electronic interaction between Ag plasmonic nanoparticles and titania support in the presence of sensitizer compound, and the formation of Ag/Ag2O composite system on the surface of titania. Influence of the state of silver on photocatalytic activity and mechanism details is discussed with special attention to irradiation wavelengths
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