Oleg Silyukov - Academia.edu (original) (raw)
Papers by Oleg Silyukov
Nanomaterials, Aug 7, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Glass Physics and Chemistry, Sep 1, 2018
New hybrid organic-inorganic derivatives HLnTiO 4 • CH 3 NH 2 (Ln = La and Nd) are obtained via t... more New hybrid organic-inorganic derivatives HLnTiO 4 • CH 3 NH 2 (Ln = La and Nd) are obtained via the intercalation of methylamine into the interlayer space of protonated layered perovskite-like titanates HLnTiO 4. The existence of three stable methylamine derivatives, namely, α-, β-, and γ-forms, is found for each of the titanates. The thermal stability of the obtained intercalation products is studied and their structural parameters are determined.
Russian Journal of Physical Chemistry A, Jun 1, 2023
Glass Physics and Chemistry, Apr 1, 2023
Russian Journal of General Chemistry, Jul 1, 2012
Layered perovskite-type oxides A 2 Ln 2 Ti 3 O 10 (A = Li, Na, K; Ln = La, Nd) prepared by solid-... more Layered perovskite-type oxides A 2 Ln 2 Ti 3 O 10 (A = Li, Na, K; Ln = La, Nd) prepared by solid-phase synthesis and their hydrated forms were characterized by the methods of TGA, XRD, and by UV-Vis spectroscopy. Photocatalytic activity of A 2 Ln 2 Ti 3 O 10 oxides in reaction of hydrogen evolution from aqueous alcoholic suspensions irradiated by UV-light was studied. It was shown that the ability to intercalation of water into interlayer space essentially affects the rate of photoinduced hydrogen evolution and is a determining factor leading to a high photocatalytic activity.
Ceramics International, Feb 1, 2019
Study on thermolysis process of a new hydrated and protonated perovskite-like oxides H 2 K 0.5 Bi... more Study on thermolysis process of a new hydrated and protonated perovskite-like oxides H 2 K 0.5 Bi 2.5 Ti 4 O 13 •yH 2 O , Ceramics International,
Catalysts, Dec 1, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Glass Physics and Chemistry, Jul 1, 2021
Abstract The ability of layered perovskite-like titanates HLnTiO 4 and H 2 Ln 2 Ti 3 O 10 (Ln = L... more Abstract The ability of layered perovskite-like titanates HLnTiO 4 and H 2 Ln 2 Ti 3 O 10 (Ln = La, Nd) to exfoliate into nanosheets in aqueous media under various conditions has been studied. Along with protonated titanates, their inorganic-organic hybrids with methylamine and n -butylamine were used as precursors for lamination. Exfoliation was carried out according to chemical and physical-chemical strategies, including stirring of initial compounds in diluted aqueous tetrabutylammonium hydroxide solution and sonication of the same mixtures, respectively. It was demonstrated that among the compounds under consideration, the methylamine derivative exfoliation degree is the highest. Successful obtainment of nanolayers with linear sizes of 30–100 nm for all the titanates considered was confirmed.
Russian Journal of General Chemistry, Apr 1, 2020
Using 1 H, 13 C, and 15 N NMR method, it was established that the formation of organic-inorganic ... more Using 1 H, 13 C, and 15 N NMR method, it was established that the formation of organic-inorganic hybrids of H 2 La 2 Ti 3 O 10 with methylamine and butylamine produces intercalated alkylamino cations, while the introduction of methanol into the interlayer space of H 2 La 2 Ti 3 O 10 is accompanied by the formation of covalent bonds.
Ceramics International, Mar 1, 2020
Protonated forms of layered perovskite-like titanates HLnTiO 4 (Ln = La, Nd), relating to the Rud... more Protonated forms of layered perovskite-like titanates HLnTiO 4 (Ln = La, Nd), relating to the Ruddlesden-Popper phases, have been used to yield inorganic-organic hybrids with the simplest representatives of amines (methylamine), alcohols (methanol), aminoalcohols (monoethanolamine) as well as n-butylamine. The possibility of the synthesis of the hybrids is studied in a wide range of conditions using both standard laboratory techniques and solvothermal/solvothermal-microwave methods. It is established that only methylamino derivatives may be synthesized in a single-phase form by a direct reaction between protonated titanates and the corresponding organic compound whereas pure n-butylamino, methanolic and monoethanolamino hybrids may be obtained on the basis of methylamino ones. For all the hybrids synthesized structure, quantitative composition, morphology and a type of a bond between inorganic and organic parts are discussed by means of powder XRD, Raman, IR and NMR spectroscopy, STA, elemental CHN analysis and SEM.
Catalysts, Apr 14, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Catalysts, Mar 18, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Catalysts, Oct 19, 2021
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
ACS omega, Mar 30, 2020
New organic−inorganic hybrids have been synthesized by the intercalation of nalkylamines (methyla... more New organic−inorganic hybrids have been synthesized by the intercalation of nalkylamines (methylamine, ethylamine, n-propylamine, n-butylamine, n-hexylamine, and n-octylamine) into the structure of the protonated and hydrated form of the perovskite-like layered titanate H 2 K 0.5 Bi 2.5 Ti 4 O 13 •H 2 O (HKBT 4 •H 2 O). The possibility of the synthesis of the hybrid materials was studied in a wide range of conditions. It was found that interlayer water plays a crucial role in the formation of intercalated hybrids. The obtained compounds were characterized with powder X-ray diffraction analysis; Raman, IR, and NMR spectroscopies; thermogravimetry (TG), TG coupled with mass spectrometry, and CHN analyses; and scanning electron microscopy. It was suggested that the intercalated n-alkylamines exist in the form of alkylammonium ions forming a paraffin-like bilayer with an average tilting angle of ∼77.5°. The obtained HKBT 4 ×RNH 2 compounds contain 0.4−0.7 n-alkylamine molecules per formula unit as well as the varied amount of intercalated water. By gentle heating, they can be obtained as dehydrated forms, which are thermally stable up to 250°C.
Glass Physics and Chemistry, Dec 1, 2008
... 122, pp. 6237–6241. 13. Sivakumar, T., Seshadri, R., and Gopalakrishnan, J., Bridging the Rud... more ... 122, pp. 6237–6241. 13. Sivakumar, T., Seshadri, R., and Gopalakrishnan, J., Bridging the Ruddlesden–Popper and the Aurivillius Phases: Synthesis and Structure of a Novel Series of Layered Perovskite Oxides (BiO)LnTiO4 (Ln = La, Nd, Sm), J. Amer. Chem. Soc., 2001, vol. ...
Molecules, Jun 16, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Journal of Solid State Chemistry, Mar 1, 2018
Formation of vanadium-containing nanostructures on the surface of protonated forms of layered per... more Formation of vanadium-containing nanostructures on the surface of protonated forms of layered perovskite-like titanates K
Diffusion and Defect Data Pt.B: Solid State Phenomena, 2013
In the present work protonic forms of layered n=1 Ruddlesden-Popper oxides HLnTiO4 (Ln=La, Nd) we... more In the present work protonic forms of layered n=1 Ruddlesden-Popper oxides HLnTiO4 (Ln=La, Nd) were used as starting point for synthesis of three series of the perovskite-like compounds. Characterization by SEM, powder XRD and TGA has been performed for the determination of the structure and composition of synthesized oxides.
Materials Chemistry and Physics
Abstract Emerging technologies aimed to tune properties of microporous materials, including zeoli... more Abstract Emerging technologies aimed to tune properties of microporous materials, including zeolitic catalysts, involve microwave processing that accelerates chemical reactions and often increases efficiency of target materials. Here we report on the results of our comprehensive study of copper-exchanged mordenites obtained from sodium mordenite with Si/Al = 6.5 and CuSO4 solution using both conventional and microwave assisted ion-exchange procedures. The current study confirms that microwave irradiation not only enhance the ion exchange but also is accompanied by a chemical reaction resulting in formation of an antlerite admixed phase, which explains the over-exchange of copper ions. Fourier transform infrared studies evidence epitaxial growth of antlerite on the surface of mordenite particles. Annealing at 450 °C leads to the transformation of antlerite into mesoporous CuO. Altogether it suggests that the resulting composite material obtained by the microwave assisted ion-exchange procedure can be considered as a promising catalyst with several different types of active sites.
Solids
Structures of partially and completely protonated Ruddlesden–Popper phases, H0.7Na0.3NdTiO4·0.3H2... more Structures of partially and completely protonated Ruddlesden–Popper phases, H0.7Na0.3NdTiO4·0.3H2O and HNdTiO4, have been established by means of neutron and X-ray diffraction analysis and compared among themselves as well as with that of the initial titanate NaNdTiO4. It was shown that while interlayer sodium cations in the partially protonated form are coordinated by nine oxygen atoms, including one related to intercalated water, in the fully protonated compound the ninth oxygen proves to be an axial anion belonging to the opposite slab of titanium-oxygen octahedra. Moreover, the partially protonated titanate was found to significantly differ from the other two in the octahedron distortion pattern. It is characterized by a weakly pronounced elongation of the octahedra towards the Nd-containing interlayer space making Ti4+ cations practically equidistant from both axial oxygen atoms, which is accompanied by a low-frequency shift of the bands relating to the asymmetric stretching mo...
Nanomaterials, Aug 7, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Glass Physics and Chemistry, Sep 1, 2018
New hybrid organic-inorganic derivatives HLnTiO 4 • CH 3 NH 2 (Ln = La and Nd) are obtained via t... more New hybrid organic-inorganic derivatives HLnTiO 4 • CH 3 NH 2 (Ln = La and Nd) are obtained via the intercalation of methylamine into the interlayer space of protonated layered perovskite-like titanates HLnTiO 4. The existence of three stable methylamine derivatives, namely, α-, β-, and γ-forms, is found for each of the titanates. The thermal stability of the obtained intercalation products is studied and their structural parameters are determined.
Russian Journal of Physical Chemistry A, Jun 1, 2023
Glass Physics and Chemistry, Apr 1, 2023
Russian Journal of General Chemistry, Jul 1, 2012
Layered perovskite-type oxides A 2 Ln 2 Ti 3 O 10 (A = Li, Na, K; Ln = La, Nd) prepared by solid-... more Layered perovskite-type oxides A 2 Ln 2 Ti 3 O 10 (A = Li, Na, K; Ln = La, Nd) prepared by solid-phase synthesis and their hydrated forms were characterized by the methods of TGA, XRD, and by UV-Vis spectroscopy. Photocatalytic activity of A 2 Ln 2 Ti 3 O 10 oxides in reaction of hydrogen evolution from aqueous alcoholic suspensions irradiated by UV-light was studied. It was shown that the ability to intercalation of water into interlayer space essentially affects the rate of photoinduced hydrogen evolution and is a determining factor leading to a high photocatalytic activity.
Ceramics International, Feb 1, 2019
Study on thermolysis process of a new hydrated and protonated perovskite-like oxides H 2 K 0.5 Bi... more Study on thermolysis process of a new hydrated and protonated perovskite-like oxides H 2 K 0.5 Bi 2.5 Ti 4 O 13 •yH 2 O , Ceramics International,
Catalysts, Dec 1, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Glass Physics and Chemistry, Jul 1, 2021
Abstract The ability of layered perovskite-like titanates HLnTiO 4 and H 2 Ln 2 Ti 3 O 10 (Ln = L... more Abstract The ability of layered perovskite-like titanates HLnTiO 4 and H 2 Ln 2 Ti 3 O 10 (Ln = La, Nd) to exfoliate into nanosheets in aqueous media under various conditions has been studied. Along with protonated titanates, their inorganic-organic hybrids with methylamine and n -butylamine were used as precursors for lamination. Exfoliation was carried out according to chemical and physical-chemical strategies, including stirring of initial compounds in diluted aqueous tetrabutylammonium hydroxide solution and sonication of the same mixtures, respectively. It was demonstrated that among the compounds under consideration, the methylamine derivative exfoliation degree is the highest. Successful obtainment of nanolayers with linear sizes of 30–100 nm for all the titanates considered was confirmed.
Russian Journal of General Chemistry, Apr 1, 2020
Using 1 H, 13 C, and 15 N NMR method, it was established that the formation of organic-inorganic ... more Using 1 H, 13 C, and 15 N NMR method, it was established that the formation of organic-inorganic hybrids of H 2 La 2 Ti 3 O 10 with methylamine and butylamine produces intercalated alkylamino cations, while the introduction of methanol into the interlayer space of H 2 La 2 Ti 3 O 10 is accompanied by the formation of covalent bonds.
Ceramics International, Mar 1, 2020
Protonated forms of layered perovskite-like titanates HLnTiO 4 (Ln = La, Nd), relating to the Rud... more Protonated forms of layered perovskite-like titanates HLnTiO 4 (Ln = La, Nd), relating to the Ruddlesden-Popper phases, have been used to yield inorganic-organic hybrids with the simplest representatives of amines (methylamine), alcohols (methanol), aminoalcohols (monoethanolamine) as well as n-butylamine. The possibility of the synthesis of the hybrids is studied in a wide range of conditions using both standard laboratory techniques and solvothermal/solvothermal-microwave methods. It is established that only methylamino derivatives may be synthesized in a single-phase form by a direct reaction between protonated titanates and the corresponding organic compound whereas pure n-butylamino, methanolic and monoethanolamino hybrids may be obtained on the basis of methylamino ones. For all the hybrids synthesized structure, quantitative composition, morphology and a type of a bond between inorganic and organic parts are discussed by means of powder XRD, Raman, IR and NMR spectroscopy, STA, elemental CHN analysis and SEM.
Catalysts, Apr 14, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Catalysts, Mar 18, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Catalysts, Oct 19, 2021
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
ACS omega, Mar 30, 2020
New organic−inorganic hybrids have been synthesized by the intercalation of nalkylamines (methyla... more New organic−inorganic hybrids have been synthesized by the intercalation of nalkylamines (methylamine, ethylamine, n-propylamine, n-butylamine, n-hexylamine, and n-octylamine) into the structure of the protonated and hydrated form of the perovskite-like layered titanate H 2 K 0.5 Bi 2.5 Ti 4 O 13 •H 2 O (HKBT 4 •H 2 O). The possibility of the synthesis of the hybrid materials was studied in a wide range of conditions. It was found that interlayer water plays a crucial role in the formation of intercalated hybrids. The obtained compounds were characterized with powder X-ray diffraction analysis; Raman, IR, and NMR spectroscopies; thermogravimetry (TG), TG coupled with mass spectrometry, and CHN analyses; and scanning electron microscopy. It was suggested that the intercalated n-alkylamines exist in the form of alkylammonium ions forming a paraffin-like bilayer with an average tilting angle of ∼77.5°. The obtained HKBT 4 ×RNH 2 compounds contain 0.4−0.7 n-alkylamine molecules per formula unit as well as the varied amount of intercalated water. By gentle heating, they can be obtained as dehydrated forms, which are thermally stable up to 250°C.
Glass Physics and Chemistry, Dec 1, 2008
... 122, pp. 6237–6241. 13. Sivakumar, T., Seshadri, R., and Gopalakrishnan, J., Bridging the Rud... more ... 122, pp. 6237–6241. 13. Sivakumar, T., Seshadri, R., and Gopalakrishnan, J., Bridging the Ruddlesden–Popper and the Aurivillius Phases: Synthesis and Structure of a Novel Series of Layered Perovskite Oxides (BiO)LnTiO4 (Ln = La, Nd, Sm), J. Amer. Chem. Soc., 2001, vol. ...
Molecules, Jun 16, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Journal of Solid State Chemistry, Mar 1, 2018
Formation of vanadium-containing nanostructures on the surface of protonated forms of layered per... more Formation of vanadium-containing nanostructures on the surface of protonated forms of layered perovskite-like titanates K
Diffusion and Defect Data Pt.B: Solid State Phenomena, 2013
In the present work protonic forms of layered n=1 Ruddlesden-Popper oxides HLnTiO4 (Ln=La, Nd) we... more In the present work protonic forms of layered n=1 Ruddlesden-Popper oxides HLnTiO4 (Ln=La, Nd) were used as starting point for synthesis of three series of the perovskite-like compounds. Characterization by SEM, powder XRD and TGA has been performed for the determination of the structure and composition of synthesized oxides.
Materials Chemistry and Physics
Abstract Emerging technologies aimed to tune properties of microporous materials, including zeoli... more Abstract Emerging technologies aimed to tune properties of microporous materials, including zeolitic catalysts, involve microwave processing that accelerates chemical reactions and often increases efficiency of target materials. Here we report on the results of our comprehensive study of copper-exchanged mordenites obtained from sodium mordenite with Si/Al = 6.5 and CuSO4 solution using both conventional and microwave assisted ion-exchange procedures. The current study confirms that microwave irradiation not only enhance the ion exchange but also is accompanied by a chemical reaction resulting in formation of an antlerite admixed phase, which explains the over-exchange of copper ions. Fourier transform infrared studies evidence epitaxial growth of antlerite on the surface of mordenite particles. Annealing at 450 °C leads to the transformation of antlerite into mesoporous CuO. Altogether it suggests that the resulting composite material obtained by the microwave assisted ion-exchange procedure can be considered as a promising catalyst with several different types of active sites.
Solids
Structures of partially and completely protonated Ruddlesden–Popper phases, H0.7Na0.3NdTiO4·0.3H2... more Structures of partially and completely protonated Ruddlesden–Popper phases, H0.7Na0.3NdTiO4·0.3H2O and HNdTiO4, have been established by means of neutron and X-ray diffraction analysis and compared among themselves as well as with that of the initial titanate NaNdTiO4. It was shown that while interlayer sodium cations in the partially protonated form are coordinated by nine oxygen atoms, including one related to intercalated water, in the fully protonated compound the ninth oxygen proves to be an axial anion belonging to the opposite slab of titanium-oxygen octahedra. Moreover, the partially protonated titanate was found to significantly differ from the other two in the octahedron distortion pattern. It is characterized by a weakly pronounced elongation of the octahedra towards the Nd-containing interlayer space making Ti4+ cations practically equidistant from both axial oxygen atoms, which is accompanied by a low-frequency shift of the bands relating to the asymmetric stretching mo...