Proceedings of the Shevchenko Scientific Society. Series Сhemical Sciences最新文献

{"title":"MORPHOLOGY AND THERMAL PROPERTIES OF ZEOLITE MECHANOCHEMICALLY MODIFIED BY Ca, Zn AND Mn(II) CATIONS","authors":"S. Halaichak, M. Golovchuk, B. Datsko, M. Yatsyshyn, S. Korniy","doi":"10.37827/ntsh.chem.2022.70.151","DOIUrl":"https://doi.org/10.37827/ntsh.chem.2022.70.151","url":null,"abstract":"An important direction of new technologies of corrosion protection of metals is the use of inhibitory pigments in the composition of paints and varnishes, which are tolerant to the environment, have high efficiency and can replace chromates. Promising anti-corrosion pigments for paints and varnishes are ion-exchange substances, in particular modified zeolites, which will provide optimal selective resistance to aggressive environmental influences. In this work the dispersion and morphology of complex pigments based on synthetic zeolite and monophosphates of calcium, zinc and manganese are investigated. It was found that the modification of zeolites by metal monophosphates by mechanochemical method in a ball mill for 60 min at a speed of 200 rpm leads to decrease in fraction to 2.0 μm by ~44%… 64% and an increase from 2.0 to 10.0 μm by ~60%. The fraction up to 2.0 μm is represented by particles of irregular globular shape > 10.0 μm - agglomerates. Thermogravimetric studies have shown that all synthesized complex pigments are characterized by thermal stability. Thermolysis is characterized by 4 stages, which correspond to the removal of physically adsorbed water, chemically sorbed water, dehydroxylation of the surface by cleavage of OH groups, and phase transitions. Modification with metal monophosphates increases the thermal stability of pigments in the sequence Na-A: Ca(H2PO4)2 - Na-A: Zn(H2PO4)2 - Na-A: Mn(H2PO4)2. Thermolysis of samples in the temperature range from 15 to 700 °С is took place during four stages, most intensively at temperatures up to 400 °С. During mechanochemical dispersion of zeolites with calcium, zinc and manganese monophosphates, the amount of physically adsorbed water increases by ~18… ~41%, and chemically sorbed water decreases by ~19… ~41%. The specific surface area of zeolite Na-A: Ca(H2PO4)2 increases by ~8%, and Na-A: Zn(H2PO4)2 and Na-A: Mn(H2PO4)2 decreases by ~50% and ~22%, respectively. This may be due to the radii of the metal cations and the fraction content up to 2.0 μm when grinding zeolites. Based on the obtained results, the synthesized zeolites can be recommended for further studies of their inhibitory properties as pigments in the composition of paints and varnishes.","PeriodicalId":396581,"journal":{"name":"Proceedings of the Shevchenko Scientific Society. Series Сhemical Sciences","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127582460","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}

{"title":"CRYSTAL STRUCTURE OF AgGa2Se3Cl(Br) COMPOUNDS","authors":"I. Ivashchenko, V. Kozák, Lyubomyr Gulay, I. Olekseyuk","doi":"10.37827/ntsh.chem.2022.70.062","DOIUrl":"https://doi.org/10.37827/ntsh.chem.2022.70.062","url":null,"abstract":"For the first time, the crystal structures of new quaternary compounds were studied by the powder method. They crystallize in tetragonal system, Sp.Gr. I-4, structural type CuIn2Te3Cl, with cell parameters: AgGa2Se3Cl (a = 5.9789(3) Å, c = 10.8592(7) Å), AgGa2Se3Br (a = 5.9767(3) Å, c = 10.8558(7) Å). From the analysis of the crystal structure it was found that the researched quaternary compounds belong to semiconductors with the general formula AІВІІІ2XVI3YVII (AІ – Cu, Ag; ВІІІ – Ga, In; XVI – S, Se; YVII  Cl, Br, I). Chalcohalide compounds of the АІСІІІ2XVI3YVIІ type refers to cation-defective compounds with a ratio of cations to anions 3:4. Their compositions can be represented by the formula Kn-uuAn, where K cations,  vacancies, A anions, u the first letter of the word unoccupied. For these compounds VEC = 4,571. If we consider the vacancy as an atom with zero valence, we get for compounds АІСІІІ2XVI3YVIІ VEC = 4. This structure refers to the tetrahedrals when the cations are surrounded by the four nearest anions. This is confirmed by the studied crystal structures of the compounds AgGa2Se3Cl(Br). The semiconductor properties can be expected from these and other compounds from the group AІВІІІ2XVI3YVII (AІ – Cu, Ag; ВІІІ – Ga, In; XVI – S, Se; YVII  Cl, Br, I).","PeriodicalId":396581,"journal":{"name":"Proceedings of the Shevchenko Scientific Society. Series Сhemical Sciences","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116490770","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}

{"title":"ENERGY BAND GAP AND THE REFRACTIVE INDEX FOR POLYANILINE THIN FILMS OF POLYANILINE IN THIN FILMS ON POLYETHYLENE SURFACE","authors":"Yuliia Stetsiv, M. Yatsyshyn, O. Reshetnyak","doi":"10.37827/ntsh.chem.2022.70.026","DOIUrl":"https://doi.org/10.37827/ntsh.chem.2022.70.026","url":null,"abstract":"e-mail: yuliia.stetsiv@lnu.edu.ua Polyaniline (PAn) films, doped with citric acid, were synthesized on a polyethylene substrate by chemical oxidative polymerization using ammonium peroxydisulfate as an oxidant. The influence of monomer concentration on the optical properties of PAn films was investigated. Optical band gap, absorption coefficient, extinction coefficient, refractive index were calculated as a function of wavelength. Different methods for determining the energy of the energy gap (Tauc method and absorption spectrum fitting) were considered. It was found that the optical band gap for all thin PAn films is due to the direct allowed optical transitions. It was found that the band gap of PAn films decreases with increasing thickness of deposited PAn films. It is established that the optical energies of the band gap of PAn films of different thickness, estimated by the results of optical absorption measurements using Tauc methods and absorption spectrum fitting, are practically commensurate and are in the range of 3.13–2.36 eV for film thicknesses equal to 18.7–137.4 nm, respectively. Based on the correlations between the optical energy of the band gap and the refractive index of semiconductors using Moss, Ravindra, Ravindra-Gupta, Reddy-Ahammed, Gerve-Vandamme, Kumar-Singh, Annani and Duffy-Reddy ratios, the value of the refractive index of PAn films was calculated and these results were compared with the values obtained from the experimental results. From the obtained results it is seen that the refractive index of PAn films increases with increasing polyaniline film thickness on a polyethylene substrate. The values obtained from the Ravindra and Ravindra-Gupta relations are the closest to the experimental ones. Therefore, the synthesized PE/PAn films can be an available material for the production of optoelectronic devices, for example, for organic field transistors and LEDs.","PeriodicalId":396581,"journal":{"name":"Proceedings of the Shevchenko Scientific Society. Series Сhemical Sciences","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122217613","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}

{"title":"RESEARCH OF PROCESSES OF HYDROGENATION OF CARBON STEEL OF DIFFERENT STRUCTURES IN HYDROGEN SULPHIDE ENVIRONMENTS","authors":"M. Khoma, S. Halaichak, B. Datsko, Marian Chuchman","doi":"10.37827/ntsh.chem.2022.70.169","DOIUrl":"https://doi.org/10.37827/ntsh.chem.2022.70.169","url":null,"abstract":"The effect of applied static loads, structure, and carbon content in steels on their hydrogenation was investigated in the paper. The content of absorbed hydrogen was determined by the method of vacuum extraction at temperatures of 200, 400, 600 and 800 °С for 720 hours, after corrosion in the NACE solution. It was shown that the hydrogenation of 0.8% C steel in the number of structures: pearlite, sorbite, troostite and martensite increased. The ferrite-pearlite structure of 0.45% C steel was the most intensively hydrogenation (19.4 ppm), sorbitic, troostitic and martensitic - less by 30...50%. The main contribution to the absorbed hydrogen was made by diffusive-mobile hydrogen. Its share in the total amount of absorbed reached~65...74% for pearlitic, 50...54% sorbitic, 64...78% troostitic and ~67% martensitic U8 steel structure. For steel 45, it is ~61...72% for ferrite-pearlitic, ~74...79% sorbitic, ~61...75% troostitic, and ~52...85% martensitic. The absorbed hydrogen content of 0.8 % C steel with sorbitic, trostitic, and martensitic structures at temperatures of 400, 600, and 800 ºС increased, while that of steel 45, on the contrary, decreased. This indicated the greater strength of the hydrogen-metal bond in 0.8 % C steel. Therefore, the structure of steels affects the sorption of hydrogen more than the carbon content. Applied static loads  = 300 MPa increased the content of hydrogen absorbed by steels by ~9...15%. On 0.8% C steel, this manifests itself more significantly - СН/С0Н= 1.3...1.8. As the imbalance of the structure increased, the resistance of steels to corrosion cracking under static loads decreased. This was determined by the dispersity of the structure and the morphology of sulfide films, which are formed during the corrosion of steels in the NACE solution. Therefore, static loads most contributed to the hydrogenation of 0.8 % C steel with a troostite structure, and 0.45% C - troostite and martensitе.","PeriodicalId":396581,"journal":{"name":"Proceedings of the Shevchenko Scientific Society. Series Сhemical Sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129729371","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}

{"title":"N-OXIDATION OF THE QUINOLINE BY PEROXY ACIDS IN THE ORGANIC SOLVENTS","authors":"V. Dutka, G. Midyana, Y. Dutka, O. Pal’chikova","doi":"10.37827/ntsh.chem.2022.70.090","DOIUrl":"https://doi.org/10.37827/ntsh.chem.2022.70.090","url":null,"abstract":"The rate oxidation reaction of quinoline with peroxy acid in warious organic solvents was studded. It has been found effective rate constants (k) and activation energy (Ea) studded process. Between the parameters of the transition state ΔН≠ and ΔЅ≠ is a linear relationship, indication the presence of counteraction effect in our series of experiments. The rate of oxidation and activation energy inflation of solvation peroxyacids and quinoline. The reaction medium affects the rate of oxidation. Correlation equations between the rate constants of the reactions in study and the physicochemical parameters of the solvents were proposed. The correlation equation for effective rate constants and the basic physicochemical parameters of solvents at 303 K has the form lg k = 0.2103 + (11.2719 ±1.7750)f(n) + (1.2126 ± 0.3906)f (ε) + +(0.0002 ± 0.0008)B – (0.0209 ± 0.0079)ET – (0.0019 ± 0.0007)δ2 – – (0.0130 ± 0.0018)Vм ( 1) N = 9; R = 0,9899; S = 0.0591; F = 119.4348, N = 9; R = 0,9737; S = ±0.0950; F = 30.3963. Correlation equations for effective rate constants for other temperatures are similar. The correlation equation for effective energies (Ea) of activation and the basic physicochemical parameters of solvents has the form lg Eак = 4.8998 – (18.7772 ± 0.4915) f(n) + (1.8883 ± 0.1038) f(ε) – – (0.0077 ± 0.0002)B – (0.0304 ± 0.0014)Eт + (0.0050 ± 0.0001) δ2 + + (0.0108 ± 0.0005)Vм (2) N = 8; R = 0.9982; S = ±0.0103; F = 1513.94. The proposed correlation equations relate the parameters of the transition state of the oxidation process and the physic-chemical parameters of solvents.","PeriodicalId":396581,"journal":{"name":"Proceedings of the Shevchenko Scientific Society. Series Сhemical Sciences","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123910478","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}

{"title":"THERMODYNAMIC PROPERTIES OF THE AgGaGe3Se8 COMPOUND AT Т≤500 K DETERMINED BY THE EMF METHOD","authors":"M. Moroz, P. Demchenko, M. Prokhorenko, B. Rudyk, L. Soliak, O. Mysina, O. Pereviznyk, O. Reshetnyak","doi":"10.37827/ntsh.chem.2022.70.053","DOIUrl":"https://doi.org/10.37827/ntsh.chem.2022.70.053","url":null,"abstract":"The division of the concentration space of the Ag–Ga–Ge–Se system in the GeSe–Se–Ga2Se3–AgGaGe3Se8–GeSe section was carried out by the EMF method. The concentration space of the Ag–Ga–Ge–Se system contains the four-phase regions GeSe2–Se–Ga2Se3–AgGaGe3Se8 (I) and GeSe–GeSe2–Ga2Se3–AgGaGe3Se8 (II). The spatial positions of these phase regions vs the point of silver were used to express equations of the overall cell reactions of synthesis of the AgGaGe3Se8 compound: 2Ag + 6GeSe2 + Ga2Se3 + Se = 2AgGaGe3Se8 and 2Ag + 7GeSe2 + Ga2Se3 = GeSe + 2AgGaGe3Se8. Reactions were performed in the positive electrodes of the following electrochemical cells (ECCs): (−) С | Ag | SЕ | R(Ag+) | PЕ | С (+), where C is graphite, Ag is the left (negative) electrode, SE is the purely Ag+ ion conducting solid electrolyte (Ag3GeS3Br-glass), PE is the right (positive) electrode, and R(Ag+) is the region of PE that contact with SE. Shifted from the left electrode to the R(Ag+) region for thermodynamic reasons Ag+ ions acted as the small nucleation centers for reconstruction of the metastable mixtures of compounds in the thermodynamically stable mixture of phases. Linear dependences of EMF vs temperature of ECCs were used to calculate the standard thermodynamic properties of the AgGaGe3Se8 equilibrium in the regions (I) and (II): ∆_f G_((I))^○= –(575,0 ± 8,9) kJ·mol −1, ∆_f H_((I))^○= –(574,7 ± 12,0) kJ·mol−1, S_((I))^○ = (515,9 ± 14,1) J·(mol·K)−1 and ∆_f G_((II))^○ = –(588,4 ± 9,4) kJ·mol−1, ∆_f H_((II))^○ = –(590,6 ± 12,9) kJ·mol−1, S_((II))^○ = (507,8 ± 13,2) J·(mol·K)−1, respectively. The relative difference between the calculated values ∆_f G_((I))^○ and ∆_f G_((II))^○ within ~2.3% and the overlap of the uncertainty intervals characterize the four-phase sections (I) and (II) by the combination of compounds of the formula composition. Moreover, values of the partial thermodynamic functions of the potential-determining component (Ag) of the AgGaGe3Se8 compound were calculated.","PeriodicalId":396581,"journal":{"name":"Proceedings of the Shevchenko Scientific Society. Series Сhemical Sciences","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132520075","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}

{"title":"THE INTERACTION OF THE COMPONENTS IN THE R2T2In1-xGax (R = La, Ce; T = Ni, Cu) SYSTEMS","authors":"N. Dominyuk, G. Nychyporuk, V. Zaremba","doi":"10.37827/ntsh.chem.2022.70.069","DOIUrl":"https://doi.org/10.37827/ntsh.chem.2022.70.069","url":null,"abstract":"This work is devoted to the study of R2T2In1-xGax (R = La, Ce; T = Ni, Cu) systems at 870 K, namely the solubility of the fourth component in compounds with the composition 2:2:1 and structural characteristics of the solid solutions. Samples for the investigation were synthesized by arc-melting of metals (purities better than 0.998) with subsequent annealing at 870 K for one month in the electric muffle furnace SNOL with automatic temperature control. The phase compositions of the alloys were characterized by means of X-ray powder diffraction (DRON-2.0M, Fe Kα-radiation, HZG 4a, Cu Kα-radiation and Guinier camera Fujifilm BAS–1800, Cu Kα-radiation) and energy dispersive X-ray analysis (scanning electron microscope Leica 420i). According to the results of experimental studies, the solubility of Gallium in the La2Ni2In and Ce2Ni2In compounds is not more than 4 at. %. The unit cell parameters of the solid solutions with Mo2FeB2-type structure are: a = 0.7627–0.7609(4), c = 0.3905–0.3898(3) nm, V = 0.2272–0.2257(1) nm3 for La2Ni2In1-0.8Ga0-0.2 and a = 0.7530–0.7503(3), c = 0.3722–0.3718(2) nm, V = 0.2110–0.2093(1) nm3 for Ce2Ni2In1-0.8Ga0-0.2. Significant solubility of indium in ternary gallides with Mo2NiB2-type structure under the conditions of the study was not detected. During the investigation of the components interaction in the R2Cu2In1-xGax (R = La, Ce) systems less 7 at.% of Gallium solubility in the ternary La2Cu2In and Ce2Cu2In compounds at 870 K was detected. The solid solutions with the Mo2FeB2-type structure can be described by formulas: La2Cu2In1-0.65Ga0-0.35 (a = 0.7737–0.7709(4), c = 0.3924–0.3936(3) nm, V = 0.2349–0.2339(1) nm3) and Ce2Cu2In1-0.65Ga0-0.35 (a = 0.7797–0.7774(3), c = 0.3991–0.3999(3) nm, V = 0.2426–0.2417(1) nm3). The peculiarities of the interaction of components in the studied and related systems are briefly discussed.","PeriodicalId":396581,"journal":{"name":"Proceedings of the Shevchenko Scientific Society. Series Сhemical Sciences","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131196260","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}

{"title":"SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF COLLOIDAL SOLUTIONS OF BICOMPONENT Ag/CuO NANOPARTICLES STABILIZED BY RAMNOLIPID","authors":"L. Bazylyak, A. Kytsya, P. Lyutyi, O. Kuntyi, A. Prokopalo, O. Karpenko","doi":"10.37827/ntsh.chem.2022.70.159","DOIUrl":"https://doi.org/10.37827/ntsh.chem.2022.70.159","url":null,"abstract":"Despite the extremely high activity of researchers in the direction of green synthesis of nano-particles of silver, copper, as well as bimetallic nanoparticles Ag/Cu-NPs, the many aspects of the synthesis of nanoparticles based on silver and copper remain unexplored, in particular, the studies on the influence of the nature of biosurfactants on the characteristics are relevant obtained nano¬particles, in particular their size, shape, etc., as well as the influence of the morphology and compo¬sition of nanoparticles on their antimicrobial properties. Therefore, the purpose of this work was to synthesize colloidal solutions of bicomponent Ag/CuO-NPs nanoparticles of different composition and to investigate their antimicrobial activity. Bicomponent Ag/CuO nanoparticles of different composition were obtained by the method of coprecipitation of Ag+ and Cu2+ cations in solution of rhamnolipid. It was found that the process of formation of monocomponent CuO nanoparticles is completed within 2.5 hours but the reduction of silver ions in aqueous solutions of RL occurs within a few minutes. The obtained Ag/CuO-NPs were studied using UV-visible spectroscopy and the method of powder diffraction of X-rays. It was found that the absorption spectra of Ag/CuO-NPs solutions are characterized by two maxima at 280 and 410 nm, which correspond to the surface plasmon resonance bands of CuO and Ag-NPs, res-pectively. Based on the obtained data, it is reasonable to assume that the obtained Ag/CuO-NPs can form core-shell structures in which the role of the core will be played by silver surrounded by a CuO shell. Taking into account the prospects of using the nanoparticles based on silver and copper as antimicrobial agents for the plant protection, the antimicrobial activity of the synthesized Ag/CuO-NPs was investigated. The gram-negative bacteria-phytopathogens were used as test microorganisms, namely Agrobacterium tumefaciens, which is the causative agent of crown gall disease of a wide range of agricultural crops and Xanthomonas campestris, which is the causative agent of the \"black rot\" disease in cruciferous vegetables. The antimicrobial activity of the synthesized colloidal solutions of Ag/CuO was evaluated by the minimum inhibitory concentration values. The results of the studies of antimicrobial activity of the synthesized Ag/CuO colloidal solutions showed that the obtained preparations effectively inhibit the growth of phytopathogenic bacteria Agrobacterium tumefaciens and Xanthomonas campestris and it was found that the obtained drugs are more active against the Xanthomonas campestris.","PeriodicalId":396581,"journal":{"name":"Proceedings of the Shevchenko Scientific Society. Series Сhemical Sciences","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116770023","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}

{"title":"FEATURES OF THE FORMATION OF SURFACE LAYERS ON METALS","authors":"O. Hertsyk, M. Kovbuz, Natalia Pandiak, Myroslava Tashak","doi":"10.37827/ntsh.chem.2022.70.128","DOIUrl":"https://doi.org/10.37827/ntsh.chem.2022.70.128","url":null,"abstract":"The practical application of metal alloys, in particular amorphous ones, often necessitates the creation of multifunctional coatings of various nature and purpose on their surfaces. The main requirements for obtaining optimal results of applying such coatings are as follows: 1. Understanding of the morphology of the surface before coating. 2. Information on the physical and mechanical properties of the metal-coating composition. 3. Testing of the adhesion strength immediately after coating. 4. The use of different methods of control of the application and functionality of the coating, depending on the operating conditions of the product. The reliability of functional coatings also depends on the preparation of the surface of the material, as well as the choice of appropriate conditions for its formation. However, regardless of the purpose, a general requirement that all coatings must meet is a good adhesion to the surface of the substrate material. It is also important to ensure the uniform thickness in different areas (protrusions and depressions), because the thickness of the coating determines the longevity of its protective effect. Also, the coatings should have very low rate of dissolution even in the most aggressive environments in which they work. Therefore, the problem of creating optimal coatings is complex and requires a comprehensive study in each specific case. In the case of industrial use of amorphous metal alloys (AMA) based on transition metals with different alloying elements, special attention must be paid to the elemental composition of the surface of the finished products, which can differ significantly from the quantitative composition of the initial charge, which depends on the nature of the components and the applied protocol of ultra-fast cooling of the melt. The difference in the elemental composition on the surface and in the volume of the amorphous alloy is also due to the possible formation of surface chemical compound i.e. metal oxides. The protective properties are evaluated by the speed of metal oxidation, the formation of a layer and the duration of its action. Comparative assessment of the reactivity of amorphous alloys Al87.0Y5.0Ni8.0, Fe73.6Cu1.0Nb2.4Si15.8B1.2, Fe78.5Ni1.0Mo0.5Si6.0B14.0, Co75.5Fe4.6Si6,B16.7 in an aqueous solution of sodium chloride was carried out using electrochemical studies. The main requirements for obtaining optimal results of applying protective coatings on crystalline and amorphous surfaces have been analyzed.","PeriodicalId":396581,"journal":{"name":"Proceedings of the Shevchenko Scientific Society. Series Сhemical Sciences","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133945232","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}

{"title":"EFFECTIVE ELECTROCATALYST FOR HYDROGEN EVOLUTION FROM WATER BASED ON VANADIUM DOPED Mo2C, Mo2N AND REDUCED GRAPHENE OXIDE","authors":"D. Mazur, Y. Kurys', V. Koshechko, V. Pokhodenko","doi":"10.37827/ntsh.chem.2022.70.007","DOIUrl":"https://doi.org/10.37827/ntsh.chem.2022.70.007","url":null,"abstract":"Molybdenum compounds (Mo2C, MoS2, MoP, Mo2N, etc.) and their composites with different nanosized carbon materials are considered to be one of the most promising Pt-free hydrogen evolution reaction (HER) electrocatalysts. Along with non-metallic dopants (N, P etc.), d-metals are also used as dopants to increase the activity of Mo-containing hybrid catalysts in HER. Thus, we have recently shown the possibility of obtaining HER nanocomposite electrocatalysts based on vanadium doped particles of Mo2C and N,P-doped reduced graphene oxide (rGO) using precursor based on polypyrrole, H3PVMo11O40 (PVMo11) and rGO – V-Mo2C/N,P-rGO. It was found that doping with vanadium atoms in situ promotes an increase in the activity of catalysts in HER, compared with the analogue obtained in the absence of V doping. The nature of the nitrogen-containing conjugated polymer can also affect the type of metal-containing particles formed during the high-temperature processing of such macromolecules together with the metal precursors. Given this, the paper shows the possibility of obtaining a promising hybrid electrocatalyst for HER based on vanadium-doped Mo2C, Mo2N and N,P-doped rGO (V-Mo2C,Mo2N/N,P-rGO) by pyrolysis of composite-precursor based on poly-5-aminoindole, PVMo11 and rGO. It was found that the simultaneous presence of Mo2C and Mo2N phases in the catalyst causes an increase in the activity of V-Mo2C,Mo2N/N,P-rGO in HER compared to the analogue containing only Mo2C phase (V-Mo2C/N,P-rGO), which is manifested in reduction in hydrogen evolution overpotential at a current density of 10 mA/cm2 (on 15-29 mV), an increase in the magnitude of exchange currents (by ~ 2.3-2.7 times), as well as in the anodic shift of the process onset potential and the reduction of Tafel slope (in alkaline electrolyte).","PeriodicalId":396581,"journal":{"name":"Proceedings of the Shevchenko Scientific Society. Series Сhemical Sciences","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115648856","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}