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The paper presents the results of the synthesis and study of CuAl layered double hydroxides (LDHs) as well as their application as catalysts for the selective hydrogenation of crotonaldehyde. Phase-homogeneous LDHs were obtained by co-precipitation and mechanochemical methods, and critical parameters ensuring the formation of the target product were identified. In the case of coprecipitation, the formation of LDH is most affected by the pH of the reaction medium and the CO32−/Al3+ ratio. The optimal CO32−/Al3+ ratio is ca. 0.5–0.8 and pH 9.5–10.0. When mechanochemical synthesis is used, at 500 m·s−2 and 60 min, it is possible to obtain a single-phase CuAl LDH, whereas at higher energies, LDH is destroyed. The mechanochemical method makes it possible not only to reduce the synthesis time and the amount of alkaline wash water but also to obtain more dispersed copper particles with a higher hydrogenating activity. The conversion of 2-butenal (T = 80 °C, P = 0.5 MPa, 180 min, ethanol) for this sample was 99.9%, in contrast to 50.5% for the catalyst obtained by co-precipitation. It is important that, regardless of the conversion, both catalysts showed high selectivity (S = 90–95%) for the double bond hydrogenation.

Novel bimetallic Pd-Co catalysts supported on the carbon material Sibunit were synthesized by an incipient wetness impregnation method and used for ethylene production by selective acetylene hydrogenation. It has been established that an increase in the Pd:Co molar ratio from 1:0 to 1:2 in 0.5%Pd-Co/C catalysts, treated in hydrogen at 500 °C, leads to an increase in the ethylene selectivity from 60 to 67% (T = 45 °C). The selectivity does not change with a further increase in the modifier concentration. The catalysts were investigated by TPR-H2, XRD, TEM HR, EDS, and XPS methods. It was shown that palladium and cobalt in the 0.5%Pd-Co/C samples form Pd(1−x)Cox phases of solid solutions with different compositions depending on the Pd:Co ratio. The cobalt concentration in the Pd-Co particles increases with an increase in the Pd:Co ratio up to 1:2 and then remains at a constant level. In addition, monometallic Co particles were present in the samples with the Pd:Co ratio higher then 1:2. The optimal combination of catalytic properties (the ethylene yield is 62–63%) is typical for catalysts with a Pd:Co molar ratio of 1:2–1:4. which is mainly due to the presence of bimetallic particles containing ~41–43% by at. of cobalt.

The development of new heterogeneous Pt-containing catalysts has retained its relevance over the past decades. The present paper describes the method to produce metal–carbon composites, Pt1−xNix/CNF, with an adjustable Pt/Ni ratio. The composites represent Pt1−xNix (x = 0.0–1.0) nanoparticles embedded within a structure of carbon nanofibers (CNF). The synthesis of the composites is based on a spontaneous disintegration of Pt1−xNix alloys in an ethylene-containing atmosphere with the formation of CNF. The initial Pt1−xNix alloys were prepared by thermolysis of multicomponent precursors. They possess a porous structure formed by fragments of 100–200 nm. As was shown by X-ray diffraction analysis, the crystal structure of the alloys containing 0–30 and 60–100 at.% Ni corresponds to a fcc lattice based on platinum (Fm-3m), while the Pt0.50Ni0.50 sample is an intermetallic compound with the tetragonal structure (P4/mmm). The impact of the Ni content in the Pt1−xNix samples on their activity in ethylene decomposition was studied as well. As was revealed, the efficiency of Pt1−xNix alloys in this process increases with the rise of Ni concentration. The composite samples were examined in an electrochemical hydrogen evolution reaction. The synthesized Pt1-xNix/CNF composites demonstrated superior activity if compared with the Pt/Vulcan commercial catalyst.

Ni(Mg)Al-layered hydroxides with molar ratios of (Ni + Mg)/Al = 2, 3, 4 and Ni/(Ni + Mg) = 0.1, 0.3, 0.5, 0.7 were synthesized by mechanochemical activation. It has been proven that the phase composition of the samples was presented by a single hydrotalcite phase up to Ni/(Ni + Mg) = 0.5. For the first time, catalysts based on Ni(Mg)Al-layered hydroxides prepared by a mechanochemical route have been studied in the reaction of furfural hydrogenation. The correlation between furfural conversion, the selectivity of the products, and the composition of the catalysts was established. The effect of phase composition, surface morphology, and microstructure on the activity of the catalysts was shown by XRD, SEM, and TEM. It was found that catalysts with Ni/(Ni + Mg) = 0.5 have the highest furfural conversion. Herewith, the product selectivity can be regulated by the (Ni + Mg)/Al ratio.

Synthesis of porous carbon materials has been carried out in two ways—by chemical and mechanochemical dehydrochlorination of polyvinyl chloride in the presence of alkali and subsequent two-stage heat treatment of the obtained polyvinylenes (carbonization up to 400°C and carbon dioxide or alkaline activation at a temperature of 850—900 and 800°C, respectively). The products obtained were studied by transmission electron microscopy and low-temperature nitrogen adsorption. It is shown that, depending on the synthesis conditions, carbon materials after activation have a developed specific surface area of 350–1100 m2/g and specific pore volume 0.3–0.47 cm3/g with a variable contribution of micropores from 30 to 85%. Thus, the effectiveness of the chosen approach to the controlled synthesis of porous CMs from PVC is confirmed.

A study on the effect of high-temperature treatment has on the thermal stability of Sibunit, a graphite-like carbon material, under the conditions of an oxidative environment depending on the presence of the active component (Pt, Pd or Ru) has been performed. Thermal analysis results show that preliminary high-temperature treatment of Sibunit raises the temperature of the onset of carbon oxidation. It is found that keeping Ru/Sibunit samples in a nitrogen–air mixture (1 : 1) for 4 h at a temperature of 400°C results in partial destruction of Sibunit’s pyrocarbon framework and an increase in the average size of Ru particles. Using Ru as an example, it is shown that ruthenium catalysts can effectively oxidize CO at temperatures no higher than 200°C and withstand overheating up to 400°C with no appreciable loss of activity.

The effect of elevated temperatures on the textural and structural characteristics of the carbon material Sibunit in an oxygen-containing atmosphere was studied depending on the preliminary treatment of Sibunit with HNO3 and the presence and the amount of an active component (Pt). According to the results of thermogravimetry, the preliminary treatment of Sibunit with HNO3 led to an increase in the temperature range of carbon oxidation, while the introduction of Pt led to a decrease in this temperature range. It was found that an exposure of Pt/Sibunit samples for 4 h in a nitrogen–air mixture at a temperature of 400°C led to an increase in the total volume and average pore diameter with a slight change in the specific surface area, and the average particle size of platinum increased from 2 to 5 nm.

The applicability of a new carbon material—carbon foam with a cellular structure synthesized from the pyrolysis products of hydrocarbon gases—as a catalyst support was demonstrated. The modification of the carbon foam by the deposition of nanoglobular carbon particles on its surface made it possible to obtain a nonporous material with a specific surface area of

The interaction between the components of a Ru–Rb/Sibunit catalyst for the decomposition of ammonia is studied via XAFS spectroscopy, X-ray diffraction with synchrotron radiation, and high-resolution transmission electron microscopy. The porous structure of the samples is examined at the stages of preparation. A set of measures reveals the presence of ruthenium in the catalyst (mainly in the metallic state) and the absence of joint phases of ruthenium and rubidium. It is found that rubidium is in an oxidized state in the catalyst in the form of compounds in direct contact with particles of active component and comparable in size to the latter, and as small clusters found mainly in the structure of carbon support.

A cellular carbon support was first obtained by modifying the surface of a cellular carbon material with pyrolytic carbon. On this support, palladium catalysts with controlled particle size of deposited metal were synthesized for the first time. By the example of the reaction of gas-phase hydrogenation of acetylene, the possibility of using such catalysts in selective hydrogenation reactions was shown.

The synthesis of porous carbon materials was carried out by mechanochemical dehydrochlorination of polyvinyl chloride in the presence of alkalis (KOH, LiOH) using a high-energy planetary mill and the subsequent two-stage heat treatment of the obtained polyvinylenes (polymers with a conjugated double bond system)—carbonization to 400°C and carbon dioxide at 850°C or alkaline activation and 800°C, respectively. The structure of the obtained products was studied by Raman spectroscopy and transmission electron microscopy, analysis of isotherms of low-temperature adsorption/desorption of nitrogen. The resulting products are (micro-, meso-) porous amorphous carbon materials with specific surface SBET from 460 to 605 m2/g, micropore volume from 0.09 to 0.21 cm3/g, and mesopore volume from 0.09 to 0.6 cm3/g

Pulsed-laser irradiation of a globular turbostratic carbon material under diverse conditions was carried. A TEM examination revealed formation of nanostructured particles (nanocapsules) under exposure to 1064 nm pulsed radiation at the power density of 108 W/cm2, whose increase to 1011 W/cm2 led to formation of structures with a higher degree of ordering. Pulsed irradiation of the initial globules at 532 nm wavelength allowed reducing the interplanar spacings of the graphene layers in the resultant nanocapsules from 0.410 to 0.346 nm. The dependence of the maximum heating temperature of the nanoparticles on the power density in the laser spot was analyzed. The influence of the heating temperature of the carbon nanomaterial on its structure and morphology was assessed.

The interaction of potassium bismuth citrate (PBC) with polysaccharides of various structures – dextran (linear) and arabinogalactan (branched) was investigated. The NMR method revealed the donor-acceptor character of the interaction of dextran with PBC in water solutions. Synchrotron radiation and transmission electron microscopy was show the formation of the anisotropic PBC-nanocrystals the covered of dextran layers.

A series of bimetallic Pd–Zn catalysts supported on the carbon material Sibunit was synthesized for selective hydrogenation of acetylene. XRD, XPS, XAFS and TEM data revealed that the structure and dispersion of bimetallic particles in Pd–Zn/Sibunit samples depend on the molar ratio Pd:Zn. The active component of the Pd–Zn(1:0.25)/Sibunit sample is a substitutional solid solution. In the catalysts with Pd:Zn ≤ 1, the interaction proceeds more completely with the transformation of FCC lattice of the solid solution into the tetragonal structure of intermetallic phase with the composition close to PdZn, whereas an excess of zinc forms the individual ZnO phase. It was found that an increase in the zinc content in Pd–Zn/Sibunit catalysts from Pd:Zn = 1:0 to 1:4 leads to dispergation of the deposited mono- and bimetallic particles from dav = 7.2 to 2.0 nm. The formation of the PdZn intermetallic compound with increasing the zinc content from Pd:Zn = 1:0 to 1:1 is accompanied by a gradual increase in selectivity to ethylene from 42% for Pd/Sibunit to 67% for Pd–Zn(1:1)/Sibunit (the reaction temperature is 95 °C), and also by a decrease in activity. The introduction of a zinc excess (Pd:Zn

Nickel catalysts with carbon-mineral supports derived from sapropel were synthesized; the effect exerted by the nature of the support (type of the initial sapropel) and active component precursor on the activity of the catalysts in the model reaction of liquid-phase nitrobenzene hydrogenation was studied. The catalysts, synthesized using the support with a smaller fraction of carbon, were more active irrespective of the precursor nature. The highest activity was observed for the catalysts synthesized from nickel nitrate and formate; nitrobenzene conversion was 65% and 51%, respectively, after 1 h of reaction. The catalysts retained high activity after six reaction cycles at 100% aniline selectivity. The presence of sulfur in the nickel precursor deteriorated the catalytic activity (convection less than 3%) due to formation of the sulfide phase.

Porous carbon–carbon composite materials (PCCCM) were synthesized by the alkaline dehydrochlorination of polyvinyl chloride solutions in dimethyl sulfoxide containing the modifying additives of a nanostructured component (NC): graphite oxide (GO), reduced graphite oxide (RGO) or nanoglobular carbon (NGC), with subsequent two-step thermal treatment of the obtained polyvinylene–NC composites (carbonization at 400 °C and carbon dioxide activation at 900 °C). The focus of the study was on the analysis and digital processing of transmission electron microscopy images to study local areas of carbon composite materials, as well as to determine the distances between graphene layers. TEM and low-temperature nitrogen adsorption studies revealed that the structure of the synthesized PCCCM can be considered as a porous carbon matrix in which either carbon nanoglobules (in the case of NGC) or carbon particles with the “crumpled sheet” morphology (in the case of GO or RGO used as the modifying additives) are distributed. Depending on the features of the introduced 5–7 wt.% nanostructured component, the fraction of mesopores was shown to vary from 11% to 46%, and SBET—from 791 to 1115 m2 g−1. The synthesis of PCCNC using graphite oxide and reduced graphite oxide as the modifying additives can be considered as a method for synthesizing a porous carbon material with the hierarchical structure containing both the micro- and meso/macropores. Such materials are widely applied and can serve as adsorbents, catalyst supports, elements of power storage systems, etc.

The controllable synthesis of carbon nanofibers (CNF) and composites based on CNF (Metals/CNF) is of particular interest. In the present work, the samples of CNF were produced via ethylene decomposition over Co-Pt (0–100 at.% Pt) microdispersed alloys prepared by a reductive thermolysis of multicomponent precursors. XRD analysis showed that the crystal structure of alloys in the composition range of 5–35 at.% Pt corresponds to a fcc lattice based on cobalt (Fm-3m), while the CoPt (50 at.% Pt) and CoPt3 (75 at.% Pt) samples are intermetallics with the structure P4/mmm and Pm-3m, respectively. The microstructure of the alloys is represented by agglomerates of polycrystalline particles (50–150 nm) interconnected by the filaments. The impact of Pt content in the Co1−xPtx samples on their activity in CNF production was revealed. The interaction of alloys with ethylene is accompanied by the generation of active particles on which the growth of nanofibers occurs. Plane Co showed low productivity (~5.5 g/gcat), while Pt itself exhibited no activity at all. The addition of 15–25 at.% Pt to cobalt catalyst leads to an increase in activity by 3–5 times. The maximum yield of CNF reached 40 g/gcat for Co0.75Pt0.25 sample. The local composition of the active alloyed particles and the structural features of CNF were explored.

The catalysts 1 wt% palladium supported on carbon nanoglobules (CNGs) were shown to be highly active in the liquid-phase hydrogenation of various nitroarenes and provided nearly 100% selectivity to aromatic amines at complete conversion under mild conditions (323 K, 0.5 MPa, 1 h). The catalytic activity (in terms of turnover frequency and substrate conversion) and selectivity depend on the kind of CNGs support, catalyst preparation method and the reaction conditions (solvent nature). The Pd/CNGs catalyst can be repeatedly used while maintaining the same catalytic performance. The excellent performances of Pd/CNGs catalysts can be due to the globular morphology of the supports as well as the absence of micropores and pronounced surface defects.

Bimetallic and monometallic composite materials containing ultra-microporous carbon, the structure of which is similar to that of activated carbon, Pd0, CoO, and possibly PdCoO2 nanoparticles are synthesized via the pyrolysis of sawdust impregnated with a solution of palladium nitrate and cobalt nitrate. According to TEM, the size distribution of metal-containing particles in the bimetallic catalysts is slightly broader than the one in monometallic catalysts, and the average particle size of the former is larger than that of the latter. Some metal-containing particles are localized on the support surface, while others are pressed into the support matrix or coated with a carbon shell. Bimetallic catalysts exhibit high stability and activity in gas-phase chlorobenzene hydrodechlorination (HDC) to form mostly benzene; in the presence of all cobalt-containing catalysts, chlorobenzene conversion is greater than 85% throughout the investigated range of temperatures (150–300°C). XPS shows that during HDC, the metals are chlorinated and the carbon shells of the metal particles are partially degraded under the action of hydrogen chloride. This is accompanied by the emergence of active metal particles on the catalyst’s surface. Introducing cobalt helps reduce the deactivation of the catalysts’ palladium-containing sites and ensures the formation of additional active sites based on CoO.

A method for the synthesis of metal–carbon nanocomposites in which metal-centered particles of the core–graphite-like shell type are distributed in the bulk of an amorphous sp2-carbon matrix is proposed. Polyvinyl chloride (PVC) was used as a carbon matrix precursor. The synthesis procedure included the following stages: The dehydrochlorination of PVC with diethylamine in a dimethyl sulfoxide solution in the presence of Co, Ni, Fe, or Cu nitrates; the carbonization of the product at 400°C; metal reduction with hydrogen at 500–620°C; and methane conversion at 620–850°C. The metal concentrations in the resulting composites were the following (%): Fe, 10; Ni, 10.8; Co, 11; and Cu, 21. The structure of the final metal–carbon nanocomposites was studied by transmission electron microscopy. The size of a metal core was 20–100 nm, and the number of graphene layers in a shell was to 50.

Catalytic properties of the tungstated alumina (WA) supported catalysts with different nature and content of active metal (Pt, Pd, Rh, Ru, Ni) were studied in the continuous flow hydrodeoxygenation of sorbitol at a temperature of 653 K, a pressure of 4.0 MPa, and weight hourly space velocity (WHSV) of 1.0 h−1. The catalysts were characterized by N2 physical adsorption, H2-TPR, CO chemisorption, TEM, and NH3-TPD. It was found that all catalysts provide complete conversion of sorbitol with the formation of C5–C7 hydrocarbons as the main products which include n-alkanes, cycloalkanes, and isoalkanes. The yield of С5–С7 hydrocarbons after 1 h of the reaction increases from 42 to about 74 mol% in a series of catalysts: 5% Ni/WA

In the present research, the process of the formation of the active components of Pd-Zn catalysts supported on carbonaceous material Sibunit prepared by the joint impregnation (Pd:Zn = 1) is studied. It was shown by means of TPR and EXAFS techniques that the interaction between palladium and zinc begins already at T > 200 °C. During the reduction in hydrogen at temperatures of 200–300 °C the surface of particles being formed is enriched with oxidized zinc. In the temperature range of 400–500 °C zinc is completely reduced, and the crystal lattice of a substitutional solid solution based on fcc lattice of palladium is restructured in tetragonal lattice of PdZn. However, an increase of the calcination temperature in H2 atmosphere (500 °C) significantly rises up the probability of partial destruction of bimetallic phase due to the partial migration of zinc atoms from the surface into the bulk of particles.

A method for synthesis of carbide containing composites by mechanical activation has been developed. A mixture of molybdenum oxide, carbon black and Al or Zn metal reductant have been treated for 15 min in air followed by a subsequent calcination in argon atmosphere at 800 °C. The elemental and phase composition, structure, texture and particle morphology of these composites were studied. Mechanically activated and calcined samples were found to contain 6.5 and 5.9% of the molybdenum carbide phase, respectively.

In the present work, adsorptive-catalytic properties and thermal stability of the systems based on ZSM-5 zeolite and γ-Al2O3, used as a binder, were studied. The zeolite was modified with silver, and the Ag loading used was 5 and 10 wt%. Characterization of the samples by a transmission electron microscopy has revealed that for the 5%Ag/ZSM-5 sample the predominant part of silver is represented by ion-exchanged forms. The 10%Ag/ZSM-5 sample contains also silver nanoparticles and clusters on the outer zeolite surface. As it was found by means of X-ray diffraction analysis, all these surface Ag species are roentgen-amorphous. Diffuse reflectance UV–vis spectroscopy confirms presence of the surface Ag clusters, which concentration increases after the high-temperature aging. The adsorption capacity of the samples was estimated using toluene as a model aromatic compound. The composition of the reaction mixture during the aging procedures was varied in order to elucidate the contribution of different silver sites to hydrocarbons sorption, their partial oxidation and oxidation of carbon monoxide.

Commercial carbon black (CB) was mechanically activated in air for 5–60 min and 100 g acceleration of milling bodies, which were represented by steel balls with the diameter of 2, 5 and 8 mm. Changes in the composition and structure of the tested objects, including their surface layers, were considered. IR spectroscopy and acid-base titration showed that mechanical activation (MA) of CB results in the formation of oxygen-containing surface functional groups in the amount of 0.21–0.34 mEq/g. The analysis of the pore texture of mechanically activated CB samples revealed that an increase in MA intensity increases the specific surface area and decreases the total pore volume. The high intensity of MA leads to the formation of the pore system in CB that differs from the initial system and consists of 10–100 nm pores and thin pores with the size of 3–5 nm. A TEM study on the morphology of mechanically activated CB samples demonstrated that activation at the high intensity results in the partial destruction of globules and the appearance of small particles with the size of 2–5 nm. A structural study showed that mechanical activation at the high intensity may lead to rearrangement of graphene layers in globules.

Based on the Sibunit carbon composite, Ru–Cs(Ba)/Sibunit catalysts with Cs(Ba) : Ru molar ratios of 0.5, 1.5, and 2.5 were obtained. The catalytic activity of the obtained promoted catalysts in the decomposition of ammonia and their thermal resistance to methanation are compared. In the reaction of ammonia decomposition, the specific activity (Wsp) of barium-containing catalysts proved to be 2 times lower than the specific activity of cesium-containing samples with the same molar M : Ru ratio. Thus, Wsp at 500°С was 29.4 mmol H2 min–1 for 0.5Cs–Ru/Sibunit and 15.4 mmol H2 g–1cat min–1 for 0.5Ba–Ru/Sibunit. It was shown that the introduction of barium at molar ratios Ba : Ru = of 0.5–2.5 significantly increases the thermal stability of the samples defined as the ratio of the weight of hydrogen obtained on the catalyst to the weight of carbon subjected to methanation. There is 52 g H2 for nonpromoted Ru/Sibunit catalyst, 370 g H2 for the 0.5Ba–Ru/Sibunit sample, 200 g H2 for the 1.5Ba–Ru/Sibunit sample, and 150 g H2 for the 2.5Ba–Ru/Sibunit sample per 1 g of carbon loss.

The interaction of platinum with carbonaceous graphite-like material Sibunit was studied. It was found that carbon covers the platinum particles during the reduction in a hydrogen flow. Chemisorption of CO over such samples has shown that just a small part of Pt surface is opened and accessible for the reagents. The carbon support was additionally pretreated by a high temperature graphitization in nitrogen. The amount of surface oxygen-containing groups was increased by a treatment with nitric acid. An examination of the Pt-loaded samples in hydrogen has revealed that the oxidative treatment does not affect the activity in the carbon hydrogenation process. Both the initial and oxidized Pt-loaded samples facilitate intensive carbon interaction with hydrogen leading to quite similar amounts of methane released. Contrary, the graphitization of the support allows one to minimize the methane formation. Lower specific surface area and absence of amorphous carbon weaken the platinum–carbon interaction and facilitate the formation of larger particles, thus complicating the realization of hydrogenation mechanism.

Three-component Ru-Ba-Cs/C catalysts supported on the graphite-like carbonaceous composite material Sibunit were synthesized. The effects of the graphitization procedure of the support (thermal treatment at 1900 °C) on the phase composition and the distribution of the components were studied. The catalytic activity in the ammonia decomposition reaction and the thermal stability of the samples were examined in comparison with the untreated support. The samples were characterized by Raman spectroscopy, XAFS, TEM, and XRD methods. It was found that in the case of untreated support, Ru presents in the form of both the metallic and partially oxidized fine particles. The graphitization of the carbon support facilitates the formation of large, well-crystallized metal particles. Barium in both samples was found to be unevenly distributed and presented mainly as large particles of carbonate. Cesium-containing species were not detected. The effect of the support graphitization on the thermal stability is comparable with catalyst modification by Ba and Cs. At the same time, combination of these effects noticeably increases the efficiency of the catalyst. Thus, the non-promoted Ru catalyst deposited on the untreated support decomposes 107 g of NH3 per 1 g of the lost carbon. Modification of the catalyst with Ba and Cs allows one to increase this value up to 498 g of NH3, while graphitization of the support and application of the combined approach were shown to give 910 and 1577 g, correspondingly.

Transmission electron microscopy and X-ray energy dispersive microanalysis have been used to study structural and chemical transformations occurring in polyvinyl chloride films containing embedded nanoglobular carbon particles after intense laser irradiation. It was established that irradiation led to the conversion of nanoglobular carbon into carbon nanocapsules with sizes of 5–10 nm. The chemical composition of the composite film samples changed after laser irradiation. Thus, the average concentration of chlorine decreased from 35 to 3 wt %, and the carbon content increased by 20–30 wt %. The possibility of obtaining carbon–carbon nanocomposite film materials with carbon nanocapsules embedded in an amorphous carbon matrix was demonstrated.

Novel macroporous iron oxide nanocomposite cryogels were synthesized and assessed as arsenite (As(III)) adsorbents. The two-step synthesis method, by which a porous nanonetwork of iron oxide is firstly formed, allowed a homogeneous dispersion of the iron oxide in the cryogel reaction mixture, regardless of the nature of the co-polymer forming the cryogel structure. The cryogels showed excellent mechanical properties, especially the acrylamide-based cryogel. This gel showed the highest As(III) adsorption capacity, with the maximum value estimated at 118 mg/g using the Langmuir model. The immobilization of the nanostructured iron oxide gel into the cryogel matrix resulted in slower adsorption kinetics, however the cryogels offer the advantage of a stable three-dimensional structure that impedes the release of the iron oxide nanoparticles into the treated effluent. A preliminary toxicity evaluation of the cryogels did not indicate any apparent inhibition of human hepatic cells activity, which together with their mechanical stability and high adsorption capacity for As(III) make them excellent materials for the development of nanoparticle based adsorption devices for drinking water treatment.

The effect of the support nature (different carbons, aluminum oxide, mixed MgAl oxide) on the activity of palladium catalysts and on the reaction routes of aqueous-phase hydrogenation of furfural at a temperature of 423 K and a pressure of 3 MPa was investigated. The carbon-supported catalysts were found to be the most active, and almost complete conversion of furfural is achieved. In the presence of these catalysts, the reaction proceeds predominantly through two parallel water-involved routes depending on the nature of carbon support: catalysts supported on carbon nanoglobules are selective to 4-oxopentanal (selectivity up to about 63%), while catalysts supported on carbon nanotubes give mainly cyclopentanone (selectivity up to 57%). The palladium catalysts based on the oxide supports (γ-Al2O3, MgAlOx) are much less active in the aqueous-phase hydrogenation of furfural compared to carbon-supported catalysts, and complete conversion of furfural does not occur (only up to 55%). In the presence of catalysts prepared using basic support (i.e., MgAl oxide), there are no reactions involving water, and furfuryl alcohol and tetrahydrofurfuryl alcohol are the principal products. According to the results of catalyst characterizations, the revealed differences in performance of palladium catalysts are caused by the effect of the support nature on the formation and dispersion of supported Pd nanoparticles, as well as by the distinctions in the structure and acid–base properties of the supports.

Textural, structural, and morphological changes occurring in globular carbon black of various particle size fractions under continuous irradiation with a continuous beam of 2.5-MeV accelerated electrons were studied by the methods of adsorption and high-resolution transmission electron microscopy. The electron irradiation leads to pronounced transformation of the solid globular framework of carbon black mainly into graphite-like nanocapsules of 10–50 nm size with the spacing between the graphene layers of the order of 0.355 nm. The observed effect leads to a decrease in the porosity (by a factor of approximately 1.65) and in the specific surface area (by a factor of 3–4) of the irradiated samples. This may be due to the transformation of the turbostratic (practically amorphous) form of carbon black into the nanostructured state with denser packing of carbon particles. The physicochemical properties of such carbon should be primarily determined by the structure of the solid framework.

The resistance of the Pd/C samples towards hydrogenation of the carbon support was studied in the temperature-programmed and isothermal regimes. Carbonaceous graphite-like material Sibunit was used as a carbon support. Pristine Sibunit was additionally graphitized via high temperature treatment (1900 °C) in an inert atmosphere. Both initial and graphitized supports were subjected to oxidative treatment in order to increase the amount of surface functional oxygen-containing groups. Palladium (1 wt%) was supported using an aqueous solution of H2PdCl4. All the samples were characterized by a low-temperature adsorption of nitrogen, transmission electron microscopy, and Raman spectroscopy. The graphitization procedure was found to decrease significantly the specific surface area of the support, while the oxidative treatment affects this parameter negligibly. Testing the Pd-containing samples in a hydrogen flow revealed the following order in accordance with amount of methane released: Pd/iSib » Pd/iSib-ox > Pd/gSib > Pd/gSib-ox.

A metal-support interaction in the carbon-supported ruthenium samples in a hydrogen medium was studied. The carbonaceous graphite-like composite material Sibunit with a specific surface area (SSA) of 320 m2/g was used as a support. The support was additionally treated at 1900 °C in an inert medium to provide the graphitization of the amorphous carbon. This procedure drops the SSA value dramatically. Both the initial and graphitized supports were also kept in a nitric acid to increase the amount of the oxygen-containing surface groups. Ruthenium was deposited from a ruthenium (II) ammonia complex. The strongest metal-support interaction resulting in an intensive hydrogenation of the carbon support was observed in the case of oxidized support. Two explanations of the phenomenon were proposed. First of all, methanation of the oxygen-containing surface groups contacting with the metal particle occurs at lower temperature and with higher rate if compared with other carbon species. Secondly, these groups provide higher hydrophilicity of the support and facilitate the formation of the well dispersed and finely distributed ruthenium particles. The graphitization procedure was found to stabilize the samples towards the hydrogenation process.

Carbon nanofibers (CNFs) have been rapidly synthesized on the surface of low-cost commercial chlorinated polymers (chlorinated polyvinyl chloride, polyvinyl chloride), which contains iron compounds, under the action of a high power ion beam at room temperature. Organic (Fe(C5H5)2) and inorganic (FeCl3⋅6H2O и Fe(NO3)3·9H2O) iron compounds were used as catalytic additions. SEM, TEM and Raman spectroscopy were used to investigate the morphologies and structure of irradiated polymers. CNFs had a most probable diameter in the range 50–90 nm and a maximum length of up to 10 μm. The maximum CNFs growth rate was estimated as 160 μm/μs. A possible growth mechanism for CNFs is discussed.

The present work is devoted to the study of doping effects of zinc, gallium and silver on the structure of active sites and catalytic properties of carbon-supported 0.5 wt% Pd catalysts in the liquid-phase selective hydrogenation of acetylene to ethylene. Carbonaceous graphite-like material Sibunit was used as a support. The reaction was performed in a medium of N-methyl-2-pyrrolidone at 55 °C. It was shown that the bimetallic Pd-Zn/C, Pd-Ga/C and Pd-Ag/C catalysts exhibit better activity and selectivity towards target product if compare with the monometallic Pd/C catalyst. The ethylene yield increases in a row as follows: Pd/C (19%)

The palladium catalysts prepared using carbon nanoglobules (CNGs) as the support and containing no more than 2 wt% Pd were shown to be highly effective for the liquid-phase hydrogenation of ethyl 4-nitrobenzoate under mild conditions. Regardless of the kind of CNGs and the catalyst preparation method, the most of the Pd/CNGs catalysts allow achieving a complete conversion of substrate giving benzocaine in a 100% yield. The Pd/CNGs catalyst is easily recycled many times without loss of its catalytic performance. The results obtained may be useful for the development of effective Pd/C catalysts for chemoselective hydrogenation of various nitroarenes.

The catalytic properties of cadmium sulfide nanoparticles in the photochemical decomposition of hydrogen peroxide are studied. It is shown that in aqueous H2O2 solutions of any concentration, cadmium sulfide accelerates the reaction and does not change its order. The quantum yield of the reaction is 1 and does not depend on the concentration of hydrogen peroxide. The scattering of light by particles and an increase in their concentration reduces the quantum yield.

At various structural-scale levels, the interaction between the aluminum alloy DT1 and a liquid eutectoid mixture of gallium and indium under the action of mechanical waves of the ultrasonic range is investigated. It is established that the deep penetration of the eutectoid mixture into the solid metal under ultrasonic action is due to the formation of channels along which the mixture moves. These channels are observed in both the axial and radial directions.

The research data on the preparation of nickel catalysts obtained from modified carbon mineral materials based on sapropel are given. The nature of these materials and their modification method were shown to have effect on the textural and acid–base properties of the support, as well as on the properties of prepared catalysts in model hydrotransformations of 1-methylnaphthalene and dibenzothiophene. The highest increase in the catalytic activity was found to occur after acid pretreatment of sapropel-based carbon mineral materials due to the formation of acid sites on the support surface and finely dispersed particles of supported nickel.

A method for fractionation of the starting carbon composite Sibunit by density was used to obtain three samples of Sibunit with different values of the specific surface area: Sib10 at 439 m2/g, Sib13 at 389 m2/g, and Sib17 at 256 m2/g. Investigation of Sibunits using both methods, that is, X-ray diffraction analysis and combination (Raman) scattering spectroscopy, did not reveal significant differences (the parameters of the crystal lattice and the ID/IG ratio). The fractionated supports were used to obtain Ru-containing catalysts for ammonia decomposition reaction (0.1 MPa, 400°C). The dependence of the specific catalytic activity calculated per 1 m2 of the support specific surface a for catalysts of the same composition (4.0% Ru and 13.6% Cs) has an extreme form. The authors connect this with two factors: the blocking support pores contain an active component and a change in features of ruthenium interactions with the promoter (Cs) of the catalyst.

The study addresses the effect of the reduction conditions of palladium polynuclear hydroxo complexes (PHC) supported on the Sibunit carbon material on the dispersion of the metal particles and the activity of 0.5%Pd/Sibunit catalysts in the selective hydrogenation of sodium 2,4,6-trinitrobenzoate to 1,3,5-triaminobenzene in an aqueous solution (temperature of 323 or 343 K, pressure of 0.5 MPa). The palladium PHC were reduced using the most common methods pertaining to catalyst preparation: liquid-phase reduction with sodium formate and reduction in a hydrogen flow at elevated temperature. It was found that high-temperature reduction in the gas phase gives rise to Pd particles with a markedly lower dispersion compared with the sample obtained under mild liquid-phase reduction conditions. The catalytic activity of the sample containing large Pd particles proved to be higher than the activity of the catalyst obtained by reduction with sodium formate.

The structural properties of Pd-Ga/γ-Al2O3 samples prepared from joint Pd(NO3)2 and Ga(NO3)3 solution and their catalytic properties in liquid-phase acetylene hydrogenation have been studied. Using temperature programmed reduction (TPR-H2), transmission electron microscopy (TEM), diffuse reflectance infrared Fourier transform spectroscopy of adsorbed CO (CO-DRIFTS) and X-ray photoelectron spectroscopy (XPS) it was found that an increase in the ethylene selectivity to ∼ 66–70% is explained by the modification of the electronic properties of palladium by gallium at a Ga:Pd molar ratio of 0.5 and by the formation of bimetallic Pd2Ga particles in the case of Ga:Pd = 2.