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Vol 69, No 11 (2024)
СИНТЕЗ И СВОЙСТВА НЕОРГАНИЧЕСКИХ СОЕДИНЕНИЙ
CO OXIDATION CATALYSTS BASED ON COMPLEX ANTIMONATES OF THE La2O3-СoO-Sb2O5 SYSTEMS
Abstract
Single-phase samples of compounds crystalized in the La2O3-CoO-Sb2O5 system have beensynthesized by several methods. Catalytic properties of these samples were studied in the COoxidation reaction. It was found that the LaCo1/3Sb5/3O6 catalyst with a rosiaite structuresynthesized by coprecipitation with hydrothermal treatment of sediment and subsequent annealinghas the largest activity at low temperatures and stability during cyclic tests. This catalyst providesthe 90% CO conversion at 265∘C. The surface of LaCo1/3Sb5/3O6 was studied using XPS, TPD O2 and IR spectroscopy. It is shown that the CO catalytic oxidation proceeds according to the Langmuir-Hinshelwood mechanism and is accompanied by Co3+↔Co2+ and Sb3+↔Sb5+ redoxprocesses with the participation of surfactants and oxygen vacancies. At the same time, antimonyions in this process act as an electron donors, the increasing concentration of which promotes theadsorption and formation of active oxygen species on the surface. The absence of contaminationof the surface during the catalytic process has been established, which eliminates the need for itsregeneration.
Russian Journal of Inorganic Chemistry. 2024;69(11):1499-1513
1499-1513
LOW-TEMPERATURE SYNTHESIS OF HIGHLY DISPERSED BARIUM ALUMINATE
Abstract
A new approach has been developed for the low-temperature synthesis of highly dispersed barium aluminate of vermicular morphology with specified characteristics (bulk density from 0.015 g/cm3, average particle size in the range of 15-87 nm). The synthesis technique includes sequential heat treatment up to 1200∘C of a concentrated aqueous solution of BaCl2, Al(NO3)3, (NH2)2CO and C6H8O7. Using physico-chemical research methods: IR spectroscopy, X-ray phase analysis, transmission and scanning electron microscopy, as well as chemical analysis, the main stages of the synthesis of BaAl2O4 are characterized.
Russian Journal of Inorganic Chemistry. 2024;69(11):1514-1521
1514-1521
THE INFLUENCE OF THE SYNTHESIS METHOD ON THE COMPOSITION, MORPHOLOGY AND CATALYTIC PROPERTIES OF NANO-SIZED BISMUTH FERRITE
Abstract
Nanocrystalline bismuth ferrite was synthesized using spray pyrolysis and citrate combustion methods. BiFeO3 samples were characterized by X-ray diffraction, infrared spectroscopy, scanning and transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The citrate and spray pyrolysis samples of bismuth ferrite were tested as catalysts for the Fenton-like reaction of the oxidative destruction of methyl orange. The influence of the synthesis method on the composition, morphology of bismuth ferrite particles, as well as catalytic activity has been established. The kinetics of the oxidative destruction of the dye in the presence of bismuth ferrite samples is satisfactorily described by a pseudo-first order model; the reaction rate constant in the case of BiFeO3 synthesized by spray pyrolysis is 0.0072 min-1, for citrate BiFeO3 it is slightly less -0.0049 min-1. The degree of destruction of methyl orange in 120 minutes without a catalyst is 7%, in the presence of spray pyrolysis bismuth ferrite - 62%, in the presence of citrate bismuth ferrite - 51%.
Russian Journal of Inorganic Chemistry. 2024;69(11):1522-1534
1522-1534
SYNTHESIS AND STUDY OF SUBMICRON BARIUM HEXAFERRITE CERAMICS OBTAINED BY LIQUID-PHASELOW-TEMPERATURE SINTERING OF BaFe12O19 NANOPARTICLES
Abstract
In this work, the problem of obtaining ceramic samples of barium hexaferrite BaFe12O19 with high values of coercivity was being solved. For this purpose, BaFe12O19 nanopowder with coercivity Hc=445 kA/m was synthesized by hydrothermal synthesis. Sintering was carried out at low temperature (900∘C) to preserve the grains in a single-domain state. To perform sintering at such a low temperature, B2O3 or Bi2O3 was added to the hexaferrite. The effect of the amount and type of additive on the phase composition, microstructure and magnetic properties of sintered hexaferrite was studied. It was shown that using Bi2O3(in the form of 0.5, 1 or 3 wt.% of Bi(NO3)3) led to no changes in the phase composition, while addition of B2O3(in the form of 0.5, 1 or 3 wt.% of H3BO3) resulted in partial transformation of hexaferrite into hematite α-Fe2O3. It was found that with increasing concentration of Bi2O3 or B2O3, the average grain size of BaFe12O19 increases,but does not exceed the critical single-domain size. This provides high Hcvalues of the sintered samples (370-420 kA/m), which makes them superior to most well-known brands of unsubstituted hexaferrites.
Russian Journal of Inorganic Chemistry. 2024;69(11):1535-1546
1535-1546
КООРДИНАЦИОННЫЕ СОЕДИНЕНИЯ
“DIIMINE-NiII-CATECHOLATE” CHROMOPHORES BASED ON PHENANTHROLINE- TYPE LIGAND SYSTEMS: MOLECULAR STRUCTURE, “LIGAND-TO-LIGAND” CHARGE TRANSFER, AND THERMAL BEHAVIOR
Abstract
A series of chromophoric complexes NiII(3,6-Cat)(Phen) (1), NiII(3,6-Cat)(DPQ) (2) and NiII(3,6-Cat)(DPPZ) (3) (where 3,6-Cat is 3,6-di-tert-butyl-catecholate dianion) has been synthesized using 1,10-phenanthroline (Phen), dipyrido[3,2-d:2’,3’-f]quinoxaline (DPQ), and dipyrido[3,2-a:2’,3’-c]phenazine (DPPZ). Chromophores 1-3 have a slightly distorted planarstructure of the coordination environment and undergo photoinduced ligand-to-ligandintramolecular charge transfer (HOMOdonor →LUMOacсeptor), thus demonstrating stronglight absorption in visible and near-IR regions. Complexes 1-3are characterized by high thermostability and complete transition to the vapor phase under reduced pressure conditions. Compound 1has high volatility, which makes it a suitable candidate for further testing in thefabrication of optoelectronic devices by “evaporation-deposition” technology.
Russian Journal of Inorganic Chemistry. 2024;69(11):1547-1564
1547-1564
SYNTHESIS AND SPECTRAL PROPERTIES OF HALOGEN SUBSTITUTED Cu(II)-TETRAPHENYLPORPHYRINS
Abstract
The exhaustive halogenation of the β-positions of Cu(II)-5,10,15,20-tetra-(2,6-difluorophenyl)porphyrin using N-bromosuccinimide and N-chlorosuccinimide in dimethylformamide was carried out. Cu(II)-β-octachloro-(2,3,4,5,6-pentafluorophenyl)porphyrin was synthesised by the interaction of Cu(II)-5,10,15,20-tetra-(2,3,4,5,6-pentafluorophenyl)porphyrin with N-chlorosuccinimide in dimethylformamide. Using the complexation reaction of β-octabromo-5,10,15,20-tetra-(2,6-difluorophenylporphyrin, β-octachloro-5,10,15,20-tetra-(2,6-difluoro-phenylporphyrin and β-octachloro-5,10,15,20-tetra-(2,3,4,5,6-pentafluorophenyl)porphyrin with copper salts in dimethylformamide under mild conditions, the corresponding copper(II) complexes were obtained. The coordination reaction kinetics of β-octabromo-5,10,15,20-tetra-(2,6-difluorophenyl-porphyrin with copper chloride in dimethylformamide has been studied. The kinetic parameters of the reaction have been calculated. The obtained compounds were identified by UV-Vis, 1H NMR spectroscopy, mass spectrometry, elemental analysis methods. X-ray diffractograms were obtained for a number of copper complexes.
Russian Journal of Inorganic Chemistry. 2024;69(11):1565-1573
1565-1573
NEODYMIUM CARBOCXYLATES (NEODECANOATE AND3,5,5-TRIMETYLHEXANOAT) FOR DEVELOPMENTOF Nd-LOADED LIQUID ORGANIC SCINTILLATORS
Abstract
The synthesis of neodymium carboxylates (neodecanoate and 3,5,5-trimethylhexanoate) and theiruse for the development of Nd-loading liquid organic scintillators is considered. Neodymiumcarboxylates were obtained by one-step (3,5,5-trimethylhexanoate) and two-step synthesis(neodecanoate). The composition of the obtained compounds was confirmed by IR spectroscopy,elemental analysis and MALDI-TOF MS. To introduce neodymium carboxylates into a liquidorganic scintillator, it is proposed to use an additional solvent, tributylphosphate. It has been shownthat the light output of the scintillator when used is higher than without it, and is more than 60% up to a neodymium concentration of 12 g/l.
Russian Journal of Inorganic Chemistry. 2024;69(11):1574-1582
1574-1582
ФИЗИЧЕСКИЕ МЕТОДЫ ИССЛЕДОВАНИЯ
SYNTHESIS AND THERMODYNAMIC PROPERTIES OF ERBIUM TITANATE
Abstract
Erbium titanate was synthesized by co-precipitation of erbium and titanium hydroxides followed by high-temperature annealing. The temperature intervals of the sequence of formation of pyrochlore-type crystal structure were determined. Measurements of the isobaric heat capacity of erbium titanate in the range of 2-1870 K were carried out by relaxation, adiabatic and differential scanning calorimetry methods. On the basis of smoothed values of heat capacity, entropy and enthalpy increment in the region 0-1900 K were calculated, the contribution of Schottky anomaly at temperatures up to 300 K was evaluated, and the Gibbs energy of erbium titanate formation at 298.15 K was calculated.
Russian Journal of Inorganic Chemistry. 2024;69(11):1583-1598
1583-1598
HEAT CAPACITY AND THERMODYNAMIC PROPERTIES OF COMPLEX OXIDES WITH β-PYROCLORE STRUCTURE RbTe1.5W0.5O6 AND Rb0.95Nb1.375Mo0.625O5.79
Abstract
The heat capacity of complex oxides with β-pyrochlore structure RbTe1.5W0.5O6 and Rb0.95Nb1.375Mo0.625O5.79 was investigated by adiabatic vacuum and differential scanning calorimetry in the temperature range of T=(6-640) K. The standard thermodynamic functions: heat capacity Cop, enthalpy [H○(T)-H○(0)], absolute entropy [S○(T)] and the Gibbs energy [G○(T)-H○(0)] for the range from T→0 to 640 K were calculated based on the obtained experimental data. The low-temperature (T<50 K) heat capacity dependence was analyzed on the basis of multifractal model and chain-layered structure topology of the studied compounds was established.
Russian Journal of Inorganic Chemistry. 2024;69(11):1599-1613
1599-1613
ФИЗИКОХИМИЯ РАСТВОРОВ
INFLUENCE OF THE STRUCTURE OF PHOSPHORYL- AND CARBONYL CONTAINING PODANDS ON THE EXTRACTION OF LANTHANOIDS(III) FROM NITRIC ACID SOLUTIONS IN THE PRESENCE OF AN IONIC LIQUID -1-BUTYL-3-METHYLIMIDAZOLIUM BIS[(TRIFLUOROMETHYL)SULFONYL]IMIDE
Abstract
The interphase distribution of lanthanoids(III) ions between aqueous solutions of HNO3 and solutions of tetrabutyldiglisolamide Bu2C(O)CH2OCH2C(O)NBu2(1), compounds R2P(O)CH2OCH2C(O)NBu2R = Bu (2), R = Ph (3) and phosphoryl-containing podands R2P(O)CH2OCH2P(O)R12R = R1= Bu (4); R = Bu, R1= Ph (5); R = R1= Ph (6)in 1,2-dichloroethane and ionic liquid - 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide has been studied. It has been established that the extraction of metal ions increases significantly in the presence of ionic liquids in the organic phase. The stoichiometry of the extracted complexes was determined, and the influence of the concentration of HNO3 in the aqueous phase and the structure of the extractant on the efficiency of extraction of metal ions into the organic phase was considered.
Russian Journal of Inorganic Chemistry. 2024;69(11):1614-1621
1614-1621
SEPARATION OF RARE EARTH ELEMENTS OF MEDIUM-HEAVY GROUP BY SYNERGISTIC MIXTURES OF METHYLTRI-n-OCTYLAMMONIUM NITRATE AND AMMONIUM SALT OF DI-2-ETHYLHEXYLPHOSPHORIC ACID
Abstract
The separation of rare earth elements of the medium-heavy group along the Gd/Tb line byliquid extraction from low-acid nitrate solutions was studied. A synergistic mixture of methyltri-n-octylammonium nitrate and ammonium salt of di-2-ethylhexylphosphoric acid was used as anextractant. The area of synergistic extraction was determined using the isomolar series method. Ithas been shown that during extraction with a mixture of extractants and an individual ammoniumsalt of di-2-ethylhexylphosphoric acid, gel formation is observed at salt concentrations of morethan 0.25 M. In the region of system stability, the maximum separation coefficient along the Gd/Tbline more than 3.8. To prevent gel formation, n-octanol and tri-n-butyl phosphate were used as amodifier.
Russian Journal of Inorganic Chemistry. 2024;69(11):1622-1630
1622-1630
НЕОРГАНИЧЕСКИЕ МАТЕРИАЛЫ И НАНОМАТЕРИАЛЫ
SYNTHESIS OF Ti2AlC IN KBr MELT: EFFECT OF TEMPERATURE AND COMPONENT RATIO
Abstract
MAX phases of various compositions have recently found increasing application due to their multilayer structure and properties that are characteristic of ceramic materials and metals. Therefore, the development of easily scalable methods for obtaining these compounds characterized by increased phase purity is of great importance. Within the framework of the work the influence on the composition and properties of such MAX phase, as Ti2AlC, conditions of its preparation with the use of protective melt of salts (on the example of KBr), in particular, ratios ofinitial reagents (n(Ti) : n(Al) : n(C)), temperature and duration of heat treatment has been studied. It was found that at the temperature 1100∘C the highest yield of Ti2AlC (94.4%) can be obtained in the case of using the molar ratio n(Ti) : n(Al) : n(C) = 2 : 1.1 : 0.9. It is shown that the use of synthesis temperatures from 900 to 1100∘C changes the content of the target MAX phase insignificantly(from 94 to 96%), the maximum content of Ti2AlC was found in the case of obtaining a sampleat the temperature 1000∘C. The influence of synthesis temperature (900, 1100 and 1200∘C) on microstructure, thermal behavior in air current and the value of electron work function was alsostudied.
Russian Journal of Inorganic Chemistry. 2024;69(11):1631-1642
1631-1642
BIMETALLIC Pt-Ag CATALYSTS SUPPORTED ON MESOPOROUS SILICON OXIDE MСM-41 IN THE 4-NITROPHENOL REDUCTION
Abstract
Mesoporous MCM-41 with a specific surface area of 1134 m2/g was synthesized. Based on it, supported mono- and bimetallic Pt-Ag catalysts with different metal ratios were prepared by incipient wetness impregnation. Using XRD and DRS methods, it was shown that after the reductive high-temperature treatment of Pt-Ag catalysts, metal nanoparticles in contact with Pt and Ag were formed on the surface. The TPR-H2 method showed an increase in the reactivity of bimetallic catalysts compared to monometallic catalysts due to the interaction of AgOx and PtOy centers. The catalysts were studied in the reduction reaction of 4-nitrophenol with sodium borohydride. A significant increase in the rate of reduction of 4-nitrophenol on bimetallic catalysts due to the synergistic effect of Pt and Ag was established.
Russian Journal of Inorganic Chemistry. 2024;69(11):1643-1653
1643-1653
DOPED LITHIUM TITANATES AND THEIR COMPOSITES WITH CARBON NANOTUBES AS ANODES FOR LITHIUM-ION BATTERIES
Abstract
Lithium titanates Li4+xTi5–xMxO12 (M = Sc, Ga, Al, Cr; x= 0, 0.05, 0.1, 0.15) and their composites with carbon nanotubes were synthesized by the sol-gel method and characterized using X-ray diffraction, scanning electron microscopy, impedance and 7Li MAS NMR spectroscopy; their electrochemical testing was carried out. Doping with trivalent cations leads to a decrease in the mobility of lithium ions in Li4+xTi5–xMxO12, which indicates the dominance of lithium transport through vacancies in these materials. The best electrochemical characteristics are demonstrated by the Li4+xTi5–xMxO12 composites with carbon nanotubes.
Russian Journal of Inorganic Chemistry. 2024;69(11):1654-1664
1654-1664