This is the first report of the dependence of the pore diameter in a titania membrane prepared by anodizing a titanium substrate in the presence of fluoride ions on the curvature of its surface. Titania membranes with uniform pores are formed on the smooth electrode surface. The pore diameter is greater in the case of negative curvature of the titanium substrate, while it is smaller in the case of

Using the density functional theory (DFT) method, the electronic and optical properties of the most stable conformers of the di(selenophen-2-yl) thieno[3,4-c]pyridine (Se-PT-Se) monomer and its oligomers were studied. Optical properties in the ultraviolet and visible regions are determined using the non-stationary theory of the density functional (TD-DFT). By extrapolating the results of DFT obtained

Theoretical aspects of the magnetocaloric effect of coordination compounds, which hold promise for the design of new cooling agents termed “molecular refrigerators,” is examined. Due to special features of the electronic structure of polynuclear gadolinium(III) complexes, these compounds hold promise for use as refrigerating materials for achieving subhelium temperatures. Analysis of the literature

The effect of pectin, gellan, and chitosan on the activity, stability, and styrene selectivity of supported palladium catalysts for the selective hydrogenation of phenylacetylene was determined. It was shown that a positive effect is achieved as a result of the formation of palladium nanoparticles with a size of 1-4 nm, which are distributed relatively uniformly over the surface of the carriers, when

It was found that composite systems with succinic acid, in which a significant part of the acid is in the voids between the particles of silica while the acid is in the form of nano- and microcrystalites, can be obtained from hydrophilic and hydrophobic silicas and their mixtures by the method of dosing mechanical loading. The textural characteristics of the composites depend on their composition,

The effect of the structure of the catalyst and the type of base on the reaction rate and product yield of the tosylation of dihydroxybenzenes in a two-phase water–dichloromethane system in the presence of pyridine N-oxide derivatives was demonstrated. It was found that with 4-dimethylaminopyridine N-oxide and potassium carbonate it is possible to obtain dihydroxybenzene tosylates with yields of more

The effect of the acid–base characteristics of M-Si oxide systems (M: Mg, Zr, La), including those doped with silver, on their catalytic properties during the conversion of ethanol and an ethanol–water mixture to produce 1,3-butadiene (BD) is described. The highest yield of BD is obtained in the presence of the Ag/Zr-Si catalyst, which is characterized by the predominance of Lewis acid sites on its

The effect of ultrasonic treatment (UST) on the catalytic properties of a Mn-containing nanostructured carbon-based catalyst prepared by liquid-phase oxidation of naphthene–paraffin concentrate was studied. It was established that ultrasonic treatment of the catalyst improves the catalytic oxidation of hydrocarbons to synthetic petroleum (oil) acids and makes it possible almost to restore the initial

The fractal dimensions of nanodispersed zirconia determined by the BET and SAXS methods are compared. The fractal dimensions were shown to depend on the characteristic dimensions of the surface areas determined by different methods. A method for calculating the surface fractal dimension using the difference between the specific surface obtained by the BET and SAXS methods is proposed.

Structural features of epoxy–silica nanocomposites obtained by cationic polymerization were studied by small-angle X-ray scattering. An increase in the amount of the inorganic phase in this system leads to greater aggregation of the silica particles. The structure of such systems is described satisfactorily be a model with multilevel fractal aggregation. Fractal analysis was used to identify the type

The catalytic properties of N-doped hydrazine-reduced graphene oxide (N-RGO) and thermally reduced graphene oxide (TRGO) in the hydrogenation of ethylene by molecular hydrogen were studied. Samples of the TRGO and N-RGO were characterized by transmission and scanning electron microscopy, X-ray diffraction, and Raman and X-ray photoelectron spectroscopy. It was shown that decrease of the oxygen content

A method is proposed for the production of methyl acetate by combining vapor-phase reactions of methanol decomposition on a CuO-NiO-ZnO/Al2O3/cordierite catalyst and subsequent carbonylation on nickel–copper catalysts supported on BAU-A activated charcoal (AC) or cordierite. A yield of 21% methyl acetate was obtained on the catalyst containing 11% NiCl2 and 32% CuCl2 on AC.

A new method is proposed for the formation of MAPbBr3 nanoparticles in situ in a dispersion of polystyrene in toluene in the absence (MAPbBr3@PS) and presence of a broad-band luminophor (MAPbBr3/GAG:Ce@PS). This method permits the lossless use of perovskite, a uniform distribution of the luminophor nanoparticles in the polymer matrix, and maintenance of a high photoluminescence quantum yield (~46%)

It was shown that the particle size of NiO nanoparticles has been controlled through the homogeneous precipitation process by using “magnetized water” which, according to the authors, is due to a change in the surface tension and viscosity of water under the influence of a magnetic field. The textural properties, shape, recovery behavior, and size distribution of NiO nanoparticles were determined using

The reasons for the deactivating effect of water on the conversion of ethanol to 1,3-butadiene in the presence of Zn-Zr(La)-Si oxide and Cu(Ag, Zn)/Ta/SiBEA zeolite catalysts are studied. The decrease in the yield of 1,3-butadiene using ethanol–water mixtures of different composition compared with rectified ethanol is due to the deactivating effect of H2O vapor on the Lewis acid sites of the catalyst

Physicochemical aspects of the formation of solutions of nanosized C60 and some other fullerenes in aqueous media have been examined. The variety of methods for the preparation of aqueous dispersions of fullerenes gives rise sometimes to substantial differences in their colloidal, spectral, and other properties, including the chemical nature of impurities, bioactivity, and toxicity. Current methods

The properties of a nanocomposite derived from reduced graphene oxide and TiO2 obtained by hydrothermal synthesis were investigated. Nanocomposite formation was confirmed by SEM as well as Raman and IR spectroscopy. The introduction of 10% rGO into the nanocomposite leads to considerably lower resistance than found for TiO2 itself. The combination of enhanced electrotransport, optical, and adsorption

The photocatalytic activity of TiO2 nanostructures in the reduction of CO2 to CH4 and oxidation of CO to CO2 was studied. It depends significantly on the concentration of hydrofluoric acid in the sol–gel system and on the conditions of post-synthesis treatment leading to the formation of oxygen vacancies. The conditions for production of samples giving maximum efficiency for these processes were determined

The preparation, structure, and functional properties of carbon nitride such as its photocatalytic, catalytic, and adsorption activities have been examined. The template synthesis of g-C3N4 allows increasing its dispersion, specific surface area, and spatial ordering, leading to enhanced photocatalytic activity of such materials in the photoreduction of carbon dioxide and larger catalytic activity

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The modern concepts underlying the control of luminescence characteristics (quantum yield, intensity, emission color) of lanthanide coordination compounds are analyzed. The influence of the electronic structure of ligands and ions of 4f elements on the luminescent properties of these metal complexes is examined in detail. Approaches for changing the quantum yield values, emission intensity and color

The sorption and diffusion of methanol and ethanol on Amberlyst 15 were studied by the quartz crystal microbalance technique in the temperature range of 20-120°C at relative pressure p/ps < 0.04. The heats of sorption (∆H) and the activation energy of diffusion (Ea) of methanol and ethanol were determined from the temperature dependence of the Henry constant and the effective diffusion coefficient

We are the first to establish that the introduction of a small amount of passivating amine (Am) during the preparation of CH3NH3PbBr3 (MAPbBr3) (MA/Am = 0.7) leads to the formation of pseudo-2D nanoparticles of this hybrid perovskite, the number of layers in which decreases going from oleylamine to hexylamine. The use of a solution of polystyrene in toluene yields more homogeneous in size stabilized

It is shown that Mg-Al-oxide catalysts in the vapor-phase condensation of 1-butanol to 2-ethyl-1-hexanol in a flow-type reactor are superior in performance to individual Mg and Al oxides on account of achieving optimal surface concentrations and ratios of acid and base sites due to the formation of Mg-O-Al sites at the phase boundary.

The structure of coordination polymers formed by a macrocyclic nickel(II) complex and aromatic carboxylates as precursors of nickel hydroxide coatings was shown to be an essential factor determining their phase composition and electrochemical characteristics as well as electrochemical properties in the oxidation of urea in basic solutions accompanied by the release of molecular hydrogen.

Samples of mesoporous TiO2 nanostructures with crystallite sizes of 8-10 nm, forming spheroidal particles of 60-170 nm with average mesopore diameter of 5.5-3.4 nm and specific surface area of 140-200 cm3/g, were obtained by the solvothermal sol–gel method with sulfuric acid mediums and subsequent calcination. With increase of the H2SO4 concentration the content of anatase in the reaction mixture and

Hydrogenation catalysts derived from palladium nanoparticles varying in size supported on maghemite (γ-Fe2O3) were obtained by varying the concentration of K2PdCl4 and polyacrylamide as well as the solution pH during catalyst preparation. These catalysts were characterized by electron microscopy, dynamic light scattering, energy dispersive analysis, and IR spectroscopy. Decreasing the size of the palladium

A study was carried out on the photovoltaic and photoconductive properties of film composites of a copolymer of styrene with nonyl methacrylate and poly-N-epoxypropylcarbazole doped with the tetranuclear metal complex Cu4L4(OCH3)4 (L− = N,N′-dibenzyl-N″-trichloroacetylphosphotriamide) using an organic intramolecular charge transfer compound as a sensitizer. In the visible spectrum, these composites