Pub Date : 2021-10-25DOI: 10.33609/2708-129x.87.09.2021.3-13
V. Ogenko, S. Orysyk, L. Kharkova, O. Yanko, Dongchu Chen
Processes of interaction between carbon quantum dots (CQDs) and solutions of Cu(II) Ni(II) and Fe(III) chlorides in the surface layer have been investigated by electron and IR spectroscopy. When hydrochloric acid is added to the aqueous suspension of CQDs, there is a significant batochromic shift of the average absorption band (AB) by 1285 cm-1 with a decrease in its intensity to ε = 23.39. The presence of copper in the suspension of CQDs at room temperature leads to a decrease in the intensity of this AB (ε = 21.80), which indicates the interaction of CQDs with metal ions. After heating the suspension for 1 and 3 hours, the gypsochromic shift of this ABs (by 335 cm-1) to 27790 cm-1 with a decrease in intensity depending on the heating time was recorded. Such changes in the UV–Vis Spectrum are due to the redistribution of the electron density of electron transitions n → π *due to the coordination of functional groups with metal ions and the appearance of transitions with charge transfer from ligand to metal (CQD→Cu2+). When heating the suspensions significantly increases the absorption intensity of the AB at 22070 cm-1: from ε = 4.59 to ε = 6.75, which indicates the formation of transitions with charge transfer from ligand to metal (ChTLM) due to the coordination of copper ions with CQD. In the absorption spectra of CQD suspensions with NiCl2 before heating, a hypsochromic shift of AB at 27305 cm-1 by 150 cm-1 and an increase in the intensity of its to ε = 4.95 were registered. That is, Ni(II) ions also form coordination bonds with functional groups on the periphery of the CQD. After heating hydrochloric acid suspensions of CQD with FeCl3, in contrast to the chlorides of previous metals, in the UV-region registered shoulder-shaped AB at 31545 cm-1, the intensity of which increases with heating time (from ε = 9.59 to ε = 12.10), and in the visible region, a weakly intense shoulder-shaped AB at 19345 cm-1 (ε = 3.71 and 4.58), associated with the presence of dd-electron transitions in the metal ion. Such changes in the absorption spectra are explained by the fact that iron may interact with CQD in different ways (in addition to coordination with functional donor groups, the formation of coordination bonds with the π-electron system of conjugated CQDs bonds), which leads to additional weak shoulder-like AB at 31545 cm-1. The IR-spectra data of CQDs showed the presence of a number of characteristic ABs for functionalized CQDs: ν(N–H) at 3260 сm1, (C=O) at 1830, 1840 and 1850 сm1, –С=O(NH) at 1770 сm1, ν(C=N) at 1680 and δ(N–H) at 1640 сm1 and 320-360 см-1 СП ν(Cu–Cl, Ni–Cl, Fe–Cl), which confirms the coordination of metals on the surface of CQDs.
{"title":"SYNTHESIS AND SPECTRAL CHARACTERISTICS OF Cu(II), Ni(II) AND Fe(III) NANOSIZED COMPLEXES ON THE SURFACE OF CARBON QUANTUM DOT","authors":"V. Ogenko, S. Orysyk, L. Kharkova, O. Yanko, Dongchu Chen","doi":"10.33609/2708-129x.87.09.2021.3-13","DOIUrl":"https://doi.org/10.33609/2708-129x.87.09.2021.3-13","url":null,"abstract":"Processes of interaction between carbon quantum dots (CQDs) and solutions of Cu(II) Ni(II) and Fe(III) chlorides in the surface layer have been investigated by electron and IR spectroscopy. \u0000When hydrochloric acid is added to the aqueous suspension of CQDs, there is a significant batochromic shift of the average absorption band (AB) by 1285 cm-1 with a decrease in its intensity to ε = 23.39. The presence of copper in the suspension of CQDs at room temperature leads to a decrease in the intensity of this AB (ε = 21.80), which indicates the interaction of CQDs with metal ions. \u0000After heating the suspension for 1 and 3 hours, the gypsochromic shift of this ABs (by 335 cm-1) to 27790 cm-1 with a decrease in intensity depending on the heating time was recorded. Such changes in the UV–Vis Spectrum are due to the redistribution of the electron density of electron transitions n → π *due to the coordination of functional groups with metal ions and the appearance of transitions with charge transfer from ligand to metal (CQD→Cu2+). \u0000When heating the suspensions significantly increases the absorption intensity of the AB at 22070 cm-1: from ε = 4.59 to ε = 6.75, which indicates the formation of transitions with charge transfer from ligand to metal (ChTLM) due to the coordination of copper ions with CQD. \u0000In the absorption spectra of CQD suspensions with NiCl2 before heating, a hypsochromic shift of AB at 27305 cm-1 by 150 cm-1 and an increase in the intensity of its to ε = 4.95 were registered. That is, Ni(II) ions also form coordination bonds with functional groups on the periphery of the CQD. \u0000After heating hydrochloric acid suspensions of CQD with FeCl3, in contrast to the chlorides of previous metals, in the UV-region registered shoulder-shaped AB at 31545 cm-1, the intensity of which increases with heating time (from ε = 9.59 to ε = 12.10), and in the visible region, a weakly intense shoulder-shaped AB at 19345 cm-1 (ε = 3.71 and 4.58), associated with the presence of dd-electron transitions in the metal ion. \u0000Such changes in the absorption spectra are explained by the fact that iron may interact with CQD in different ways (in addition to coordination with functional donor groups, the formation of coordination bonds with the π-electron system of conjugated CQDs bonds), which leads to additional weak shoulder-like AB at 31545 cm-1. \u0000The IR-spectra data of CQDs showed the presence of a number of characteristic ABs for functionalized CQDs: ν(N–H) at 3260 сm1, (C=O) at 1830, 1840 and 1850 сm1, –С=O(NH) at 1770 сm1, ν(C=N) at 1680 and δ(N–H) at 1640 сm1 and 320-360 см-1 СП ν(Cu–Cl, Ni–Cl, Fe–Cl), which confirms the coordination of metals on the surface of CQDs.","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80843233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-25DOI: 10.33609/2708-129x.87.09.2021.14-34
I. Lisovskyi, M. Barykin, S. Solopan, A. Belous
Lithium-ion batteries (LIB`s) are widely used in consumer electronics, mobile phones, personal computers, as well as in hybrid and electric vehicles. Liquid electrolytes, which mainly consist of aprotic organic solvents and lithium-conductive salts, are used for the transfer of lithium ions in LIB`s. However, the application of liquid electrolytes in LIB`s leads to a number of problems, the most significant of which are the risk of battery ignition during operation due to the presence of flammable organic solvents and loss of capacity due to the interaction of liquid electrolyte with electrode materials during cycling. An alternative that can ensure the safety and reliability of lithium batteries is the development of completely solid state batteries (SSB`s). SSB`s are not only inherently safer due to the absence of flammable organic components, but also have the potential to increase significantly the energy density. Instead of a porous separator based on polypropylene saturated with a liquid electrolyte, the SSB`s use a solid electrolyte that acts as an electrical insulator and an ionic conductor at the same time. The use of a compact solid electrolyte, which acts as a physical barrier that prevents the growth of lithium dendrites, also allows using lithium metal as the anode material. It is desirable to use oxide systems as the solid electrolytes for SSB`s, as they are resistant to moisture and atmospheric air. Among the lithium-conducting oxide materials, which exhibit relatively high lithium conductivity at a room temperature and can be used as a solid electrolyte in the completely solid-state batteries, lithium-air batteries and other electrochemical devices, the most promising materials are ones with NASICON, perovskite and garnet-type structures. The phase transformations that occur during the synthesis of complex lithium-conductive oxides, namely Li1.3Al0.3Ti1.7(PO4)3 with the NASICON-type structure, Li0.34La0.56TiO3 with the perovskite-type structure and Li6.5La3Zr1.5Nb0.5O12 with the garnet-type structure by the solid-state reactions method in an air were investigated. The optimal conditions for the synthesis of each of the above-mentioned compounds were determined.
{"title":"FEATURES OF PHASE TRANSFORMATIONS IN THE SYNTHESIS OF COMPLEX LITHIUM-CONDUCTING OXIDE MATERIALS","authors":"I. Lisovskyi, M. Barykin, S. Solopan, A. Belous","doi":"10.33609/2708-129x.87.09.2021.14-34","DOIUrl":"https://doi.org/10.33609/2708-129x.87.09.2021.14-34","url":null,"abstract":"Lithium-ion batteries (LIB`s) are widely used in consumer electronics, mobile phones, personal computers, as well as in hybrid and electric vehicles. Liquid electrolytes, which mainly consist of aprotic organic solvents and lithium-conductive salts, are used for the transfer of lithium ions in LIB`s. However, the application of liquid electrolytes in LIB`s leads to a number of problems, the most significant of which are the risk of battery ignition during operation due to the presence of flammable organic solvents and loss of capacity due to the interaction of liquid electrolyte with electrode materials during cycling. An alternative that can ensure the safety and reliability of lithium batteries is the development of completely solid state batteries (SSB`s). SSB`s are not only inherently safer due to the absence of flammable organic components, but also have the potential to increase significantly the energy density. Instead of a porous separator based on polypropylene saturated with a liquid electrolyte, the SSB`s use a solid electrolyte that acts as an electrical insulator and an ionic conductor at the same time. The use of a compact solid electrolyte, which acts as a physical barrier that prevents the growth of lithium dendrites, also allows using lithium metal as the anode material. \u0000It is desirable to use oxide systems as the solid electrolytes for SSB`s, as they are resistant to moisture and atmospheric air. Among the lithium-conducting oxide materials, which exhibit relatively high lithium conductivity at a room temperature and can be used as a solid electrolyte in the completely solid-state batteries, lithium-air batteries and other electrochemical devices, the most promising materials are ones with NASICON, perovskite and garnet-type structures. \u0000The phase transformations that occur during the synthesis of complex lithium-conductive oxides, namely Li1.3Al0.3Ti1.7(PO4)3 with the NASICON-type structure, Li0.34La0.56TiO3 with the perovskite-type structure and Li6.5La3Zr1.5Nb0.5O12 with the garnet-type structure by the solid-state reactions method in an air were investigated. The optimal conditions for the synthesis of each of the above-mentioned compounds were determined.","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90793115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-25DOI: 10.33609/2708-129x.87.09.2021.35-44
N. Semenishyn, S. Smola, Mariia Rusakova, N. Rusakova
Isomeric ditopic corroles and complexes of Yb (III), Nd (III) and Er (III) based on them were synthesized and corrole-photosensitized 4f-luminescence in near infrared region was revealed. The structure of isomeric complexes allows adjusting the distance between the corrole core and lanthanide ion. The obtained results show that the sensitization mechanism changes drastically for both different lanthanides and isomeric forms.
{"title":"4f-LUMINESCENCE OF LANTHANIDE IONS IN REGIOISOMERIC CORROLE COMPLEXES","authors":"N. Semenishyn, S. Smola, Mariia Rusakova, N. Rusakova","doi":"10.33609/2708-129x.87.09.2021.35-44","DOIUrl":"https://doi.org/10.33609/2708-129x.87.09.2021.35-44","url":null,"abstract":"Isomeric ditopic corroles and complexes of Yb (III), Nd (III) and Er (III) based on them were synthesized and corrole-photosensitized 4f-luminescence in near infrared region was revealed. The structure of isomeric complexes allows adjusting the distance between the corrole core and lanthanide ion. The obtained results show that the sensitization mechanism changes drastically for both different lanthanides and isomeric forms.","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75419226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-25DOI: 10.33609/2708-129x.87.09.2021.45-54
L. Leybovych, Borys Dymo, Sergey Anastasenko, Yurii Yevstigneyev
The change in the viscosity of diesel fuel with dissolved hydrogen, the rate of dissolution of hydrogen in the diesel fuel, and the hydrogen diffusion coefficient in diesel fuel were experimentally determined. Dissolving hydrogen in liquid fuel changes its physical-chemical properties. It has been found that the viscosity and density of diesel fuel change little when it is saturated with hydrogen. The flashpoint in a closed crucible is reduced by 3–4 °C. The rate of dissolution of hydrogen in diesel fuel has been investigated. It has been found that the diffusion coefficient of hydrogen in diesel fuel depends significantly on the initial concentration of H2 in the fuel. The liquid fuel is advisable to supply with saturated hydrogen for the safety of the heat engine operation. The design of the hydrogen fuel saturation system with a special hydrogen sensor based on the MQ-8 sensor was proposed. The system of protection of the research stand from unauthorized emissions of hydrogen into the environment has been worked out. The protection ensures the shutdown of the stand equipment when the hydrogen concentration in the zone of its generation and supply to the fuel is at the level of 1%.
{"title":"RESEARCH OF THE PHYSICAL PROPERTIES OF DIESEL FUEL-HYDROGEN MIXTURES","authors":"L. Leybovych, Borys Dymo, Sergey Anastasenko, Yurii Yevstigneyev","doi":"10.33609/2708-129x.87.09.2021.45-54","DOIUrl":"https://doi.org/10.33609/2708-129x.87.09.2021.45-54","url":null,"abstract":"The change in the viscosity of diesel fuel with dissolved hydrogen, the rate of dissolution of hydrogen in the diesel fuel, and the hydrogen diffusion coefficient in diesel fuel were experimentally determined. Dissolving hydrogen in liquid fuel changes its physical-chemical properties. It has been found that the viscosity and density of diesel fuel change little when it is saturated with hydrogen. The flashpoint in a closed crucible is reduced by 3–4 °C. The rate of dissolution of hydrogen in diesel fuel has been investigated. It has been found that the diffusion coefficient of hydrogen in diesel fuel depends significantly on the initial concentration of H2 in the fuel. The liquid fuel is advisable to supply with saturated hydrogen for the safety of the heat engine operation. The design of the hydrogen fuel saturation system with a special hydrogen sensor based on the MQ-8 sensor was proposed. The system of protection of the research stand from unauthorized emissions of hydrogen into the environment has been worked out. The protection ensures the shutdown of the stand equipment when the hydrogen concentration in the zone of its generation and supply to the fuel is at the level of 1%.","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73107151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-24DOI: 10.33609/2708-129x.87.08.2021.99-115
A. Mishchenko, E. Trunova, T. Makotryk
Mono- and mixed-ligand complexes of La (III) with aliphatic β-ketoesters were synthesized in the solid state. The complexes have the general formulas LаL2OH·H2O (L=meacac, etacac, alacac) and La(meacac)2X·nCH3OH(X = NO3, CH3COO; n = 1, 2). Their composition, structure, and thermal properties were established by chemical and thermal analysis, IR spectroscopy. It is shown that β-ketoesters are coordinated to the La (III) ion bidentate-cyclically into monoligand hydroxocomplexes. Ligand complexes with methylacetoacetate have an oligomeric structure. They consist of cationic fragments [La(meacac)2]+ with bridged connection of the nitrate or acetate anions. The thermal destructions of LaL2OH·H2O (L = meacac, etacac, alacac), La(meacac)2NO3· 2CH3OH and La(meacac)2(CH3COO)·CH3OH were studied for the first time in the helium dynamic atmosphere by TGA-MS in the temperature range of 25–900 °C. Depending on the ligand, dehydratation of the hydroxo-complexes takes place in the 120–180 (meacac), 120–190 (etacac) or 110–160 °C (alacac) temperature range, and the mass loss corresponds with the detachment of one water molecule. Decomposition of mixed-ligand complexes starts with the detachment of methanol in the 60–100 °C range. For La(meacac)2NO3·2CH3OH the decomposition process is attended with oxidation of methanol to carbon dioxide due to reduction of the nitrate-ion to nitrogen dioxide. Further heating to 300–400 °C leads to destruction of organic parts of the complexes attended with the release of low-molecular oxygen-containing organic compounds (aldehydes, ketones, alcohols), carbon dioxide and water. At ~500 °C all the La(III) complexes under study totally decompose, yielding the oxycarbonate La2O2CO3, which was fixed by IR spectroscopy. Under further heating to 850 °С oxycarbonate gradually decomposes to La2O3 liberating CO2.
{"title":"THERMODESTRUCTION OF Lа(III) COORDINATION COMPOUNDS WITH ALIPHATIC β-KETOESTERS","authors":"A. Mishchenko, E. Trunova, T. Makotryk","doi":"10.33609/2708-129x.87.08.2021.99-115","DOIUrl":"https://doi.org/10.33609/2708-129x.87.08.2021.99-115","url":null,"abstract":"Mono- and mixed-ligand complexes of La (III) with aliphatic β-ketoesters were synthesized in the solid state. The complexes have the general formulas LаL2OH·H2O (L=meacac, etacac, alacac) and La(meacac)2X·nCH3OH(X = NO3, CH3COO; n = 1, 2). Their composition, structure, and thermal properties were established by chemical and thermal analysis, IR spectroscopy. It is shown that β-ketoesters are coordinated to the La (III) ion bidentate-cyclically into monoligand hydroxocomplexes. Ligand complexes with methylacetoacetate have an oligomeric structure. They consist of cationic fragments [La(meacac)2]+ with bridged connection of the nitrate or acetate anions. \u0000The thermal destructions of LaL2OH·H2O (L = meacac, etacac, alacac), La(meacac)2NO3· 2CH3OH and La(meacac)2(CH3COO)·CH3OH were studied for the first time in the helium dynamic atmosphere by TGA-MS in the temperature range of 25–900 °C. Depending on the ligand, dehydratation of the hydroxo-complexes takes place in the 120–180 (meacac), 120–190 (etacac) or 110–160 °C (alacac) temperature range, and the mass loss corresponds with the detachment of one water molecule. Decomposition of mixed-ligand complexes starts with the detachment of methanol in the 60–100 °C range. For La(meacac)2NO3·2CH3OH the decomposition process is attended with oxidation of methanol to carbon dioxide due to reduction of the nitrate-ion to nitrogen dioxide. Further heating to 300–400 °C leads to destruction of organic parts of the complexes attended with the release of low-molecular oxygen-containing organic compounds (aldehydes, ketones, alcohols), carbon dioxide and water. At ~500 °C all the La(III) complexes under study totally decompose, yielding the oxycarbonate La2O2CO3, which was fixed by IR spectroscopy. Under further heating to 850 °С oxycarbonate gradually decomposes to La2O3 liberating CO2.","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74433525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-24DOI: 10.33609/2708-129x.87.08.2021.116-126
A. Bliznyuk, V. Kozin
Thanks to the unique combination of physicochemical properties, niobium and its compounds are widely used in various fields of science and technology. The main areas of niobium’s applications are the production of superconductors, nuclear energy, chemical engineering, metallurgy, manufacture of optically active materials, thin-film lithium batteries, fuel cells. The aim of this work is to study the processes that take place on the niobium electrode in aqueous solutions of hydrofluoric acid, as well as to establish the composition of niobium compounds that are formed. The paper presents the results of studies the behavior of the niobium electrode in aqueous solutions 0.25 N. hydrofluoric acid. The kinetic parameters of the processes occurring at the phase boundary are determined. It was found that the anodic polarization of the niobium electrode is accompanied by the formation of a passive layer, the destruction of which is facilitated by increasing the polarization potential and fluorine anions, in the presence of which complex fluoroiobate anions [NbF7]2- and [NbOF5]2-are formed. Cathodic polarization of niobium is accompanied by the formation of hydrides on its surface, which causes an increase in the overvoltage of hydrogen evolution. The anodic polarization of the niobium electrode in a solution of hydrofluoric acid causes the formation on its surface of a passive layer, which is destroyed with increasing potential. In the Nbo–NbO2–0.25 –0.25 n HF system, [NbF7]2-anions are formed, as evidenced by bands in the region of 500 nm on the electron absorption spectra. The rate constants of [NbF7]2- and [NbOF5]2- formation are estimated at 3.78 • 10-3 s-1 and 5.18 • 10-3 s-1, respectively. The reduction of hydrogen at the niobium cathode from a solution of hydrofluoric acid is accompanied by the formation of hydrides, which causes an increase in the overvoltage of hydrogen evolution and high values of the angular coefficients of the Tafel dependence.
由于其独特的物理化学组合性质，铌及其化合物被广泛应用于各个科学技术领域。铌的主要应用领域是生产超导体、核能、化学工程、冶金、制造光学活性材料、薄膜锂电池、燃料电池。这项工作的目的是研究在氢氟酸水溶液中铌电极上发生的过程，以及确定形成的铌化合物的组成。本文介绍了铌电极在0.25 N.氢氟酸水溶液中的性能研究结果。确定了在相边界处发生的过程的动力学参数。研究发现，铌电极的阳极极化过程伴随着钝化层的形成，增加极化电位和氟离子有利于钝化层的破坏，在钝化层中形成了配合的氟酸盐阴离子[NbF7]2-和[NbOF5]2-。铌的阴极极化伴随着其表面氢化物的形成，导致析氢过电压升高。铌电极在氢氟酸溶液中的阳极极化导致其表面形成钝化层，该钝化层随着电位的增加而被破坏。在Nbo-NbO2-0.25 -0.25 n HF体系中，形成了[NbF7]2阴离子，电子吸收光谱显示在500 nm区域。[nbof7]2-和[NbOF5]2-的形成速率常数分别为3.78•10-3 s-1和5.18•10-3 s-1。氢氟酸溶液在铌阴极还原氢的同时，氢化物的形成导致析氢过电压的增加和塔菲尔依赖角系数的高值。
{"title":"NIOBIUM’S BEHAVIOR IN AQUEOUS HYDROFLUORIC ACID SOLUTION","authors":"A. Bliznyuk, V. Kozin","doi":"10.33609/2708-129x.87.08.2021.116-126","DOIUrl":"https://doi.org/10.33609/2708-129x.87.08.2021.116-126","url":null,"abstract":"Thanks to the unique combination of physicochemical properties, niobium and its compounds are widely used in various fields of science and technology. The main areas of niobium’s applications are the production of superconductors, nuclear energy, chemical engineering, metallurgy, manufacture of optically active materials, thin-film lithium batteries, fuel cells. The aim of this work is to study the processes that take place on the niobium electrode in aqueous solutions of hydrofluoric acid, as well as to establish the composition of niobium compounds that are formed. The paper presents the results of studies the behavior of the niobium electrode in aqueous solutions 0.25 N. hydrofluoric acid. The kinetic parameters of the processes occurring at the phase boundary are determined. It was found that the anodic polarization of the niobium electrode is accompanied by the formation of a passive layer, the destruction of which is facilitated by increasing the polarization potential and fluorine anions, in the presence of which complex fluoroiobate anions [NbF7]2- and [NbOF5]2-are formed. Cathodic polarization of niobium is accompanied by the formation of hydrides on its surface, which causes an increase in the overvoltage of hydrogen evolution. The anodic polarization of the niobium electrode in a solution of hydrofluoric acid causes the formation on its surface of a passive layer, which is destroyed with increasing potential. \u0000In the Nbo–NbO2–0.25 –0.25 n HF system, [NbF7]2-anions are formed, as evidenced by bands in the region of 500 nm on the electron absorption spectra. The rate constants of [NbF7]2- and [NbOF5]2- formation are estimated at 3.78 • 10-3 s-1 and 5.18 • 10-3 s-1, respectively. \u0000The reduction of hydrogen at the niobium cathode from a solution of hydrofluoric acid is accompanied by the formation of hydrides, which causes an increase in the overvoltage of hydrogen evolution and high values of the angular coefficients of the Tafel dependence.","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73205821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-24DOI: 10.33609/2708-129x.87.08.2021.127-137
R. Panteleimonov, O. Boichuk, K. Pershina, V. Ogenko
Electrochemical impedance spectroscopy was used to study the electrical parameters of graphite-graphene systems with different mass concentrations of graphene. Graphene was synthesized using two methods of plasma arc discharge from aqueous and non-aqueous medium (water and liquid nitrogen) to determine the impact of graphite concentration, water, and heat treatment of graphene on electrical parameters (conductivity and electrostatic capacity) of the graphite-graphene mixture. The average values of active resistance and electrostatic capacity of these systems are obtained. The optimal ratio of components with high capacitance and conductivity, which was 1: 1. The influence of heat treatment adsorbed on the graphene surface of the water and mass fraction of graphite on the change of electrical parameters of the system is shown. Comparison of the values of capacity and active resistance of the samples showed that the presence of water in graphene reduces the average values of capacity relative to graphene without water by 10 times and symbolically increases the active resistance at a mass ratio of graphene to graphite 1: 3, and at a ratio of 1: 1 values are proportional. Comparison of resistance, capacitance, and charge distribution calculations in a graphite-graphene mixture in the frequency range 10–2 ÷ 103 Hz established the effect of heat treatment on increasing the values of capacitance and active resistance. Heat treatment at 2500C of graphene, synthesized from an aqueous medium, leads to an increase in the values of capacitance and conductivity, which occurs due to a different distribution of charges on the surface. Analysis of charge distribution maps shows that water adsorbed on the surface of graphene in the presence of a significant amount of graphite can be a factor in interfering with the distribution of charge carriers and significantly reduce the conductivity and electrostatic capacity of the system.
{"title":"IMPACT OF THE GRAPHENE SYNTHESIS AND CONCENTRATION CONDITIONS ON ELECTRICAL PARAMETERS OF GRAPHENE — GRAPHITE SYSTEM","authors":"R. Panteleimonov, O. Boichuk, K. Pershina, V. Ogenko","doi":"10.33609/2708-129x.87.08.2021.127-137","DOIUrl":"https://doi.org/10.33609/2708-129x.87.08.2021.127-137","url":null,"abstract":"Electrochemical impedance spectroscopy was used to study the electrical parameters of graphite-graphene systems with different mass concentrations of graphene. Graphene was synthesized using two methods of plasma arc discharge from aqueous and non-aqueous medium (water and liquid nitrogen) to determine the impact of graphite concentration, water, and heat treatment of graphene on electrical parameters (conductivity and electrostatic capacity) of the graphite-graphene mixture. The average values of active resistance and electrostatic capacity of these systems are obtained. The optimal ratio of components with high capacitance and conductivity, which was 1: 1. The influence of heat treatment adsorbed on the graphene surface of the water and mass fraction of graphite on the change of electrical parameters of the system is shown. Comparison of the values of capacity and active resistance of the samples showed that the presence of water in graphene reduces the average values of capacity relative to graphene without water by 10 times and symbolically increases the active resistance at a mass ratio of graphene to graphite 1: 3, and at a ratio of 1: 1 values are proportional. Comparison of resistance, capacitance, and charge distribution calculations in a graphite-graphene mixture in the frequency range 10–2 ÷ 103 Hz established the effect of heat treatment on increasing the values of capacitance and active resistance. Heat treatment at 2500C of graphene, synthesized from an aqueous medium, leads to an increase in the values of capacitance and conductivity, which occurs due to a different distribution of charges on the surface. Analysis of charge distribution maps shows that water adsorbed on the surface of graphene in the presence of a significant amount of graphite can be a factor in interfering with the distribution of charge carriers and significantly reduce the conductivity and electrostatic capacity of the system.","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89529373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-24DOI: 10.33609/2708-129x.87.08.2021.63-81
P. Torchyniuk, O. V’yunov, V. Yukhymchuk, O. Hreshchuk, S. Vakarov, A. Belous
The organic-inorganic perovskite films CH3NH3PbI3 were synthesized from solutions with different ratios (1:1, 1:2 and 1:3) of initial reagents (PbI2 and CH3NH3I) in a DMF solvent. XRD and Raman spectroscopy shows that the perovskites are formed according to different schemes depending on the ratio of PbI2 and CH3NH3I. At the ratio 1:1 of initial reagents, three intermediate compounds are formed: (CH3NH3)2(DMF)xPbI4, (CH3NH3)2(DMF)2Pb3I8, (CH3NH3)3(DMF)PbI5. At the ratio 1:2 of initial reagents four intermediate compounds are formed: in addition to the above phases, the phase (CH3NH3)2(DMF)2Pb2I6 is found. And at the ratio 1:3 of initial reagents, only two intermediate phases, (CH3NH3)2(DMF)xPbI4 and (CH3NH3)3(DMF)PbI5, are observed. The morphology of the perovskite films was established to depend primarily on the ratio of the initial reagents. The temperature of heat treatment changes only the grain size of films.
{"title":"PHASE FORMATION PROCESSES OF ORGANIC-INORGANIC CH3NH3PbI3 PEROVSKITES USING A DMF SOLVENT","authors":"P. Torchyniuk, O. V’yunov, V. Yukhymchuk, O. Hreshchuk, S. Vakarov, A. Belous","doi":"10.33609/2708-129x.87.08.2021.63-81","DOIUrl":"https://doi.org/10.33609/2708-129x.87.08.2021.63-81","url":null,"abstract":"The organic-inorganic perovskite films CH3NH3PbI3 were synthesized from solutions with different ratios (1:1, 1:2 and 1:3) of initial reagents (PbI2 and CH3NH3I) in a DMF solvent. XRD and Raman spectroscopy shows that the perovskites are formed according to different schemes depending on the ratio of PbI2 and CH3NH3I. At the ratio 1:1 of initial reagents, three intermediate compounds are formed: (CH3NH3)2(DMF)xPbI4, (CH3NH3)2(DMF)2Pb3I8, (CH3NH3)3(DMF)PbI5. At the ratio 1:2 of initial reagents four intermediate compounds are formed: in addition to the above phases, the phase (CH3NH3)2(DMF)2Pb2I6 is found. And at the ratio 1:3 of initial reagents, only two intermediate phases, (CH3NH3)2(DMF)xPbI4 and (CH3NH3)3(DMF)PbI5, are observed. The morphology of the perovskite films was established to depend primarily on the ratio of the initial reagents. The temperature of heat treatment changes only the grain size of films.","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91198445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-24DOI: 10.33609/2708-129x.87.08.2021.82-98
V. Chernii, I. Tretyakova, Larysa Tomachynska, Y. Gerasymchuk, S. Chernii, V. Pekhnyo
The article is devoted to methods of synthesis, the structure, and spectral characteristics of zirconium and hafnium phthalocyaninates with out-of-plane coordinated ligands. The general scheme for the synthesis of out-of-plane coordinated Zr and Hf phthalocyanines includes obtaining initial dichloride or dihydroxo complexes, which then undergo substitution reactions with -dicarbonyl compounds, hydroxybenzoic, sulfo- and aliphatic carboxylic acids, etc. In the case of polyphenols, which are bidentate ligands, one ligand is coordinated to the central atom of the macrocycle. If -dicarbonyl compounds or carboxylic acids are introduced into the reaction, two ligands are coordinated. The reactivity of the out-of-plane coordinated ligands of Zr and Hf phthalocyanines was also investigated. In all obtained out-of-plane coordinated Zr and Hf phthalocyanines, the ligands are located in the cis position relative to the plane of the phthalocyanine macrocycle. X-ray diffraction, NMR, and UV-Vis spectroscopy have proved this arrangement of ligands. According to the X-ray diffraction data of Zr and Hf dibenzoylmethanato phthalocyanines, the metal atom is out of the plane of the phthalocyanine macrocycle, which itself is not planar. The central atoms are located almost in the middle between the N4 planes of the phthalocyanine macrocycle and the O4 of the extraplanar ligands. The UV-Vis spectra of out-of-plane coordinated Zr and Hf phthalocyanines in organic solvents have a typical appearance for most metal phthalocyanines, characterized by a B-band of absorption in the region of 335–350 nm, a Q-band at 680-690 nm, and its satellite in the region of 615–620 nm. If the extraplanar ligand is a chromophore (e.g., curcumin or condensed derivatives of dehydroacetic acid), there are additional absorption bands in UV-Vis spectra located between the B- and Q-bands. The influence of the nature of the central metal atoms, ligands and solvents on the fluorescent properties of the out-of-plane coordinated Zr and Hf phthalocyanines was also discussed.
{"title":"OUT-OF-PLANE COORDINATED ZIRCONIUM(IV) AND HAFNIUM(IV) PHTHALOCYANINATES","authors":"V. Chernii, I. Tretyakova, Larysa Tomachynska, Y. Gerasymchuk, S. Chernii, V. Pekhnyo","doi":"10.33609/2708-129x.87.08.2021.82-98","DOIUrl":"https://doi.org/10.33609/2708-129x.87.08.2021.82-98","url":null,"abstract":"The article is devoted to methods of synthesis, the structure, and spectral characteristics of zirconium and hafnium phthalocyaninates with out-of-plane coordinated ligands. The general scheme for the synthesis of out-of-plane coordinated Zr and Hf phthalocyanines includes obtaining initial dichloride or dihydroxo complexes, which then undergo substitution reactions with -dicarbonyl compounds, hydroxybenzoic, sulfo- and aliphatic carboxylic acids, etc. In the case of polyphenols, which are bidentate ligands, one ligand is coordinated to the central atom of the macrocycle. If -dicarbonyl compounds or carboxylic acids are introduced into the reaction, two ligands are coordinated. The reactivity of the out-of-plane coordinated ligands of Zr and Hf phthalocyanines was also investigated. In all obtained out-of-plane coordinated Zr and Hf phthalocyanines, the ligands are located in the cis position relative to the plane of the phthalocyanine macrocycle. X-ray diffraction, NMR, and UV-Vis spectroscopy have proved this arrangement of ligands. According to the X-ray diffraction data of Zr and Hf dibenzoylmethanato phthalocyanines, the metal atom is out of the plane of the phthalocyanine macrocycle, which itself is not planar. The central atoms are located almost in the middle between the N4 planes of the phthalocyanine macrocycle and the O4 of the extraplanar ligands. The UV-Vis spectra of out-of-plane coordinated Zr and Hf phthalocyanines in organic solvents have a typical appearance for most metal phthalocyanines, characterized by a B-band of absorption in the region of 335–350 nm, a Q-band at 680-690 nm, and its satellite in the region of 615–620 nm. If the extraplanar ligand is a chromophore (e.g., curcumin or condensed derivatives of dehydroacetic acid), there are additional absorption bands in UV-Vis spectra located between the B- and Q-bands. The influence of the nature of the central metal atoms, ligands and solvents on the fluorescent properties of the out-of-plane coordinated Zr and Hf phthalocyanines was also discussed.","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72593500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-26DOI: 10.33609/2708-129X.87.07.2021.3-24
A. Ennan, R. Dlubovskii, R. Khoma
The review is devoted to non-woven sorption-filtering materials (NSFM) widely used equipment for gas cleaning from toxic gaseous and vaporous substances. The use of ion-exchange fibrous materials (IFM) as NSFM and the peculiarities of their preparation and structure have been analyzed. A lot of attention is paid to the mechanisms of chemisorption processes using IFM and to the role of water in their successful implementation. Individual options and some regularities of fibrous anionites, cationites, and polyampholytes interaction due to exchange reactions, neutralization, reduction-oxidation, complexation and precipitation with gaseous and vaporous substances are considered on specific examples.
{"title":"NON-WOVEN ION-EXCHANGE FIBROUS MATERIALS IN AIR SANITARY CLEANING","authors":"A. Ennan, R. Dlubovskii, R. Khoma","doi":"10.33609/2708-129X.87.07.2021.3-24","DOIUrl":"https://doi.org/10.33609/2708-129X.87.07.2021.3-24","url":null,"abstract":"The review is devoted to non-woven sorption-filtering materials (NSFM) widely used equipment for gas cleaning from toxic gaseous and vaporous substances. The use of ion-exchange fibrous materials (IFM) as NSFM and the peculiarities of their preparation and structure have been analyzed. A lot of attention is paid to the mechanisms of chemisorption processes using IFM and to the role of water in their successful implementation. Individual options and some regularities of fibrous anionites, cationites, and polyampholytes interaction due to exchange reactions, neutralization, reduction-oxidation, complexation and precipitation with gaseous and vaporous substances are considered on specific examples.","PeriodicalId":23394,"journal":{"name":"Ukrainian Chemistry Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84046727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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