We have reviewed the state-of-the-art in heterogeneous photocatalytic systems derived from various semiconductors, their composites, and other materials for the selective hydrogenation of different classes of organic compounds including alkynes, alkenes, aromatic hydrocarbons, and compounds with unsaturated carbon-nitrogen bonds. Selective transformations of halogen-containing compounds including dehalogenation

The sorption of Cs+, Sr2+, and \( {\mathrm{UO}}_2^{2+} \) ions on bulk ammonium molibdophosphate (AMP) and also on compositions obtained by its deposition on pyrogenic titanium and silicon dioxides and silica gel during sol–gel synthesis is studied. With AMP/support compositions it is possible to increase the specific sorption capacity with respect to Cs+, Sr2+, and \( {\mathrm{UO}}_2^{2+} \) ions

The structural and spectral characteristics of sulfated spherical mesoporous titanium dioxide (TiO2-S), obtained by hydrothermal sol–gel synthesis in the presence of sulfuric acid, are studied by XRD, SEM, BET, and IR spectroscopy. The acid–base and catalytic characteristics of TiO2-S and commercial TiO2 in the oligomerization of glycerol are compared. The activation of glycerol on the surface of the

C,S-Doped TiO2 nanoparticles with diameter 55-85 nm were obtained by a solvothermal sol-gel method with subsequent calcination; the diameter of the component crystallites was 9-11 nm. An increase in the thiourea concentration in the reaction mixture reduced the anatase content, while increasing the particle size, specific surface area, as well as carbon and sulfur contents. The photocatalytic activity

With the aim of developing drug delivery systems, it was shown that nanoparticles of mesoporous silica molecular sieve MCM-41 with average size 100-150 nm and specific surface 655 m2/g could include 202 mg of emodin per one gram of the carrier and release more than 85% of this compound at pH 8 during 48 h.

On the basis of an investigation of the catalytic characteristics of iron-containing catalysts deposited on carbon nanotubes (CNT) and zirconium dioxide in the steam reforming of bioethanol at 300-500 °C it was shown that Fe/CNT exhibits high activity and productivity with respect to hydrogen at relatively low temperature. At this catalyst high conversion of ethanol (94%) and high selectivity for hydrogen

The interaction of electromagnetic radiation with ordered and disordered arrays of noble metal nanoparticles, leading to the excitation of various modes of surface plasmon states in them, is analyzed. The dipole localized surface plasmon resonance in isolated nanoparticles and the influence of various size effects on its optical response are considered. The effect of dipole-dipole interaction between

An environmentally friendly and cost-effective two-stage catalytic method is developed for the synthesis of unsaturated esters. Naphthenic acids are prerared by catalytic oxidation of a narrow diesel fraction isolated from Balakhan oil on cobalt-containing multiwalled carbon nanotubes mixed with manganese naphthenate. Unsaturated esters are synthesized by subsequent reaction with unsaturated alcohols

The diffusion of methanol in a catalyst pellet containing H-ZSM-5 zeolite and aluminum oxide before and after coke deposition in the conversion of methyl alcohol into dimethyl ether and C2–C4 alkenes is studied. It is shown that the diffusion regime of methanol is anomalous and that the anomalous diffusion exponent does not depend on coke deposition of the catalyst. The discovered features are caused

The effect of neodymium addition in the composition of complex bismuth cuprates Bi2Sr2–xNdxCaCu2Oy (0 ≤ x ≤ 0.1) on their structural and electrophysical characteristics and catalytic properties is found. It is established that increase in the neodymium content is accompanied by antibate (inverse) change in the unit cell parameters, increased structural defectiveness, and slight increase of the superconducting

It is shown that post-synthetic thermal treatment of graphitic carbon nitride (g-C3N4), obtained by pyrolysis of melamine, in molten potassium and lithium salts leads to a sixfold increase in its photocatalytic activity in the selective oxidation of benzyl alcohol by air to benzaldehyde in visible light at room temperature, and this is much higher when oxygen is used as oxidant. The conversion of benzyl

Materials based on tin dioxide doped with antimony with additions of cerium and palladium are synthesized in order to create highly sensitive and fast-responding semiconductor sensors for hydrogen. It is shown that introduction of Ce and Pd into SnO2/Sb2O5 increases the response of the sensor to microconcentrations of H2 (40 ppm). The fundamental possibility of using the developed materials to create

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

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

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

The relationship between the crystal and porous structure of titanium phosphate modified by hydrothermal, microwave, and mechanochemical treatment and its sorption characteristics with respect to Cs, Sr, and U(VI) ions was investigated. It was established that increase of the content of hydrophosphate phase, specific surface area, and volume and size of mesopores increases the sorption capacity and

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

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

Brownian dipole photomotors derived from betaine and merocyanine dyes are examined. With a specific type of molecular photoexcitation and a specific relationship of the dipole moments of the ground and excited states, directed motion of the photomotor becomes symmetry-forbidden; the forbiddenness can be removed by molecular polarization effects. These effects become the predominant factor governing

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.

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

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%)

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.

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

The available data on the photocatalytic activation of carbon monoxide are summarized. The most important directions of research and development in this area are examined. The related electronic processes are analyzed and reaction mechanisms in these systems are proposed. The most promising directions for further research in this area are indicated.

Recent work is reviewed concerning photocatalytic systems derived from graphitic carbon nitride (GCN) for the selective oxidation of various organic compounds including saturated and unsaturated hydrocarbons, alcohols, and organic sulfides. Examples are given for oxidative coupling of a series of organic compounds with the formation of carbon–nitrogen and carbon–carbon bonds as well as cyclization

It was shown that mechanochemical treatment of 1 : 1 MoO3–CeO2 oxide mixture leads to the formation of nanosized particles with core–shell type of structure with a layer of amorphous molybdenum oxide on a core of nanocrystalline cerium oxide. It was established that the synthesized nanocomposites are highly active and selective catalysts for the oxidation of ethanol to acetaldehyde at low temperatures

The morphology, phase composition, and catalytic activity in the reaction of CO oxidation of semiconductor palladium-containing sensor nanomaterials based on SnO2 were studied in order to create sensors for carbon monoxide. It was found that materials containing 0.2 wt.% Pd have maximum sensitivity to CO due to the optimum rate of catalytic reaction on their surface between CO activated on the palladium

The effect of the nature of the support and the method of preparation of indium–aluminum(zirconium) oxide compositions on their acid–base characteristics, which determine the catalytic activity in oxidative dehydrogenation of propane with participation of CO2, was established. The highest selectivity for propylene (51%) is achieved over the In2O3–Al2O3 catalyst, which is due to the presence on its

A method was developed for the synthesis of ion-coordinated polysilsesquioxanes (OSS-M) by reaction of amphiphilic carboxyl-containing oligosilsesquioxanes (OSS-COOH) with Co and Ni acetates. The OSS-M contain two types of crystalline phases, one of which is formed as a result of interaction of the alkyl chains while the other results from the formation of hydrogen bonds and coordination bonds. The

The effect of molybdenum oxide as modifying additive on the catalytic properties of the catalyst NiO/Al2O3 obtained by the “solution combustion” method in the carbon dioxide conversion of methane was studied. It was established that the addition of 1 wt.% MoO3 to the 3 wt.% NiO/γ-Al2O3 composition leads to an increase in the specific surface area of the catalyst and the mobility of the surface oxygen

The hydrodeoxygenation of methyl isobutyl ketone (MIBK) to give 2-methylpentane (2MP) in the liquid phase proceeds with high selectivity on bifunctional catalysts containing Pt nanoparticles and a Keggin heteropoly acid. This reaction was found to proceed most efficiently on a catalyst with 1% Pt and 25% H3PW12O40 on SiO2 (Pt/HPW/SiO2) at 170 °C to give 2MP with 73% selectivity and 52% conversion of

High-rate electrochemical systems as well as materials and electrolytes for such systems are briefly described. An optimized citrate method is presented for the synthesis of nanosized electrode materials with electrochemical properties comparable to the properties of the best commercial samples. Possible criteria for an ideal electrode material are formulated and the theoretical high-rate limit of

The photoluminescence and photostability of CdTe/CdS nanoparticles encapsulated in matrices of potassium dihydrogen orthophosphate, potassium bromide, calcium carbonate, and barium sulfate were studied. The greatest photostability was found for a composite with a monocrystalline KH2PO4 matrix. This stability is related to the hindered diffusion of oxygen to the implanted CdTe/CdS quantum dots.

Enhanced Förster resonance energy transfer was found for donor–acceptor pairs of cationic dyes in the presences of silver nanoparticles (NPs) in solution. This enhancement is attributed both to an increase in the fluorescence intensity of the dyes and the direct effect of local plasmon resonance of the NPs on the energy transfer rate constant. Even in the case of low energy transfer efficiency, a significant

Catalytic activities of nanomaterials based on tin dioxide with various palladium contents in the oxidation of CH4 and sensitivities of adsorption semiconductor sensors to methane based on them were studied. It was shown that responses of the sensors to methane are determined by the catalytic activites of the materials of their gas sensitive layers in the oxidation of CH4 by oxygen chemisorbed on active

This is the first demonstration of the feasibility of using the interaction of paramagnetic sites of mechanochemically nanostructured graphite particles with aliphatic alcohols (ethanol and octanol) to change the properties of graphenes formed in the liquid-phase exfoliation of thus modified samples of nanostructured graphite. The presence of various functional groups was confirmed spectroscopically

The photoconductive and photovoltaic properties of film composites derived from poly-Nepoxypropylcarbazole and additives of some indole derivative dyes, namely, squaraine, thiosquaraine, and croconaine, were studied. Such composites were found to have hole-type photoconductivity. The internal photoelectric effect is a function of the photogeneration of charge carriers from the dye molecules and transport

A summary and analysis are offered for the data available in the literature as well as the results of our own research on photocatalytic reduction processes on various semiconductor catalysts. A number of approaches are examined for the improvement of semiconductor catalysts, in particular, through alteration of morphology, increasing the amount of surface defects, doping by metal and nonmetallic ions

Inhibition by hydrogen peroxide in the radical chain aerobic oxidation of alkylarenes is reported. A kinetic scheme for this process and an equation describing the oxidation kinetics of an alkylarene in the presence of HOOH are presented. The inhibitory effect of H2O2 was found to decrease with increasing rate constant of the chain termination step by peroxyl radicals of thesubstrate undergoing oxidation

New composite materials derived from a porous luminescent zinc-containing coordination polymer and organic dyes, namely, 5-(4-diethylamino)benzylidene)pyrimidine-2,4,6(1H,3H,5H)-trione (KR) and methylene blue (MB) have been prepared. Upon excitation of the polymer matrix, the composite with KR was shown to display dual luminescence attributed to energy transfer between the luminophores, while there

It was established that modifying additives CeO2, SiO2, and H3PO4 change the catalytic properties of compositions based on ZrO2 in the conversion of ethanol into 1-butanol due to a change in the phase composition of ZrO2, which determines its acid–base properties. As a result of stabilization of the tetragonal ZrO2 phase with additions of CeO2 and H3PO4 an increase in basicity occurs, leading to an