The search for new active catalysts for the pyrolysis of hydrocarbons to produce carbon nanofibers remains an urgent task. In the present work, a series of porous Co-Pd(x) alloys, where x = 2–12 at%, were synthesized and studied. The synthesis of the alloys was performed by reductive thermolysis of multicomponent precursors obtained by co-precipitation of ammonia complex salts of cobalt and palladium in acetone. The composition of the prepared alloys corresponded to that specified during the synthesis. As was revealed by X-ray diffraction analysis, the alloy samples are mixtures of solid solutions based on the hcp and fcc phases of cobalt. The alloys are characterized by a branched 3D microstructure, formed by grains ranging in size from 1 to 3 microns and connected by bridges. The carbon productivity of Co-Pd alloys in the ethylene pyrolysis process exceeded that of pure cobalt by more than two orders of magnitude. Note that the monometallic palladium sample is not active at all under the applied conditions. The maximum carbon yield, exceeding 200 g/gcat, was achieved over the alloy containing 7 at% Pd. The obtained alloys demonstrated a significant short-time productivity compared to the systems reported earlier. The synthesized composite material is represented by carbon nanofibers with a developed specific surface area (∼ 300 m2/g) and containing dispersed particles of the initial Co-Pd alloy embedded in their structure. The set of unique properties of the obtained Co-Pd/CNF materials allows one to consider them a potential candidate for future catalytic studies.

The T-x phase diagram of the Na2MoO4-Li2MoO4 system was revised and two compounds, Na7Li(M & ocy;O4)4 (exists above 435 degrees C) and Na3-xLi1+x(MoO4)2 (0 <= x <= 0.2) were found, which melt incongruently at 544 and 515 degrees C, respectively. Orthorhombic Na7Li(M & ocy;O4)4 of a new structure type contains the [Li(MoO4)4]7- clusters of the central LiO4 tetrahedron sharing vertices with four MoO4 tetrahedra; the clusters are connected through NaO6 and NaO5 polyhedra in two types of layers, which alternate along the c axis. In monoclinic Na2.82Li1.18(MoO4)2, isostructural with Na3Li(MoO4)2, the trigonal bipyramids of NaO5 and (Na, Li)O5 share edges to form six- membered ribbons arranged along (101) in parquet-like layers resembling cuspidine-like layers with four- membered ribbons in Na7Li(M & ocy;O4)4. The layers in Na 2.82 Li 1.18 (MoO 4 ) 2 are connected by the MoO4 and LiO4 tetrahedra into a 3D framework. Under metastable crystallization conditions, the spinel-type Li2MoO4(sp) crystals were also obtained and structurally studied. Calculations of bond-valence-based energy barriers for potential diffusion of the lithium and sodium ions show probable 1D sodium-ion conductivity for Na7Li(M & ocy;O4)4. Possible 3D lithium-ion transport pathway in Li2MoO4(sp) passes through common triangular faces surrounding Li in octahedral 16d position and empty tetrahedral 8b site.

Multicomponent alloys attract growing attention to be applied in various fields of science and technology. In the present study, Ni52Fe22Cr15Cu11 alloy was produced via a single-stage method of electric explosion of wire. It was shown that this method makes it possible to obtain a phase-pure powder (solid solution with a fcc structure, a = 3.583 & Aring;) consisting of spherical nanoparticles with an average diameter of similar to 70 nm. According to chemical analysis data, the formed alloy nanoparticles are close in composition to the target ratio of metals. Depending on the treatment procedures such as reduction in hydrogen, heating in argon, calcination in air, and catalytic chemical vapor deposition of C-2-C-4 hydrocarbons, the alloy undergoes different changes. The evolution of the phase composition and magnetic properties of the alloy was monitored using X-ray diffraction analysis and ferromagnetic resonance spectroscopy. As found, the alloy exhibits the phase stability while treating in argon only. Its treatment in hydrogen at temperatures of 500 degrees C and above facilitates the damage of the solid solution. During the catalytic chemical vapor deposition process performed at 650 degrees C for 30 min, the carbon yield reached the value of 42 g/g(cat). According to transmission electron microscopy, the morphology of the deposited carbon is represented by a set of nanofibers with a mosaic structure. The resulting carbon nanofibers have a specific surface area of similar to 330 m(2)/g and a pore volume of similar to 0.8 cm(3)/g.

Lithium- and sodium-ion batteries (LIBs and SIBs) suffer from the significant degradation of electrochemical performance at low temperatures. This work presents promising hybrid anodes synthesized by the rapid thermolysis of ammonium tetrathiomolybdate and graphene oxide (GO) at 600 and 700 °C. Transmission electron microscopy revealed the formation of MoS2 crystallites oriented along or perpendicular to the surface of reduced GO (rGO) layers. X-ray photoelectron spectroscopy found the covalent C-S bonds connecting components in the MoS2/rGO hybrids. The MoS2/rGO_600 hybrid showed higher specific capacities in LIBs of 1370 mAh/g, 835 mAh/g, and 711 mAh/g at a current density of 0.1 A/g and temperatures of 25 °C, 0 °C, and -20 °C, respectively, due to the presence of excess sulfur in the sample. Increasing the current density to 2 A/g retained 78 and 34% of the capacity at 25 °C and -20 °C. In SIBs, the MoS2/rGO_700 hybrid showed more promising results, achieving 550 mAh/g at 0.1 A/g and 400 mAh/g at 2 A/g, while lowering the temperature to -20 °C retained 48 and 17% of the capacity. Such good SIB performance is attributed to the enrichment of the sample with vertically oriented MoS2 layers covalently bonded to the rGO surface.

Reactions of HS-Arf (S-Arf = S-C6F5, S-C6F4-CF3) with AuI utilizing a new atom-economy method result in corresponding [Au(S-Arf)]n metal-organic coordination polymers, which were studied by DSC, SEM-EDX, TGA, IR, and PL. Treatment of these complexes with pyridine under mild conditions results in the transformation of the starting polymers into new [{Au(py)2}{Au(S-Arf)2}]n complexes of the polymeric structure, which were isolated and characterized by single-crystal X-ray diffraction (SCXRD). The linear [Au(py)2]+ cations combine with linear [Au(S-Arf)2]- anions via Au···Au interactions into infinite chains. Such interactions were studied by quantum-chemical calculations. Treatment of [Au(S-C6F4-CF3)]n with DMSO gives crystals of [Au4(S-C6F4-CF3)4]n·nDMSO that have a unique polymeric structure.

In the present work, a series of Ni-doped carbon xerogels were prepared via resorcinol-formaldehyde polycondensation and subsequent pyrolysis of organic xerogels. As found, introducing nickel acetate into the resorcinol-formaldehyde gels does not lead to the reduction of Ni or the formation of large Ni particles. Due to the even distribution of acetate ions in the organic xerogel matrix, their decomposition occurs at a temperature of 520 °C, when the matrix is almost disintegrated. This gives additional amounts of carbon oxides, which are released at this temperature and affect the porous structure. Carbon xerogel containing 2.5 wt

Crystals of copper bis(heptafluorodimethyloctanedionate) (Cu(fod)2) have been grown by evaporation of solvent from solutions. Crystals of monoclinic syngony (I) have been obtained from toluene, while crystals of monoclinic (I) and triclinic (II) syngony have been obtained from acetonitrile. Crystallographic data: P21/c, a = 13.1863 (6), b = 9.8118 (4), c = 10.6997 (6), β = 113.633(2)° for I; 1̅ , a = 10.7941(12), b = 11.4759(14), c = 12.5263(13), α = 115.350(4)°, β = 102.957(4)°, γ = 100.999(4)° for II. Crystal packings I and II have the same structure of molecules. Crystal structures I and II are molecular and consist of discrete Cu(fod)2 molecules. Temperature dependences for saturated vapor pressure have been obtained by flow method for liquid and crystalline (phase I) Cu(fod)2 in the range 314–393 K. Thermal stability of the compound is determined, thermodynamic parameters of sublimation and evaporation have been established.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

A method for the synthesis of microdispersed Fe–Pd (0–10 atom

Formic acid is a liquid organic hydrogen carrier from which hydrogen can be released together with CO2 by catalytic decomposition. The development of supported Ni catalysts for H-2 production is important. Here, the effects of Ni state/dispersion are considered. For this purpose, three samples were prepared with about 3 wt% Ni deposited on porous N-doped carbon. The first sample contained predominantly Ni nanoparticles (similar to 2 nm), the second contained Ni clusters (<1 nm), and the third - single-atom Ni sites. The catalysts showed close activity in the gas-phase reaction. However, a minimum apparent activation energy of 105 kJ/mol and a maximum selectivity towards H-2 production of 99% were achieved for the single-atom Ni catalyst. The nature of its singleatom sites was established to correspond to Ni-N-4 and Ni-O-4, which showed greater stability under the conditions of the catalytic reaction.

Abstract Hybrid composites of gold nanoparticles (Au NPs) with polymer hydrogels are promising platforms for the development of new materials that can respond to external stimuli (chemical, physical, mechanical), reversibly absorb/release water and reagents, act as plasmonic sensors, and also be triggers of photochemical processes and photothermal actuators of micromechanical processes. In our study we have (1) proposed a one-step method for the synthesis of a hybrid composite of Au NPs with polyacrylamide hydrogel (PAAm) by the reduction of HAuCl 4 with acrylamide (AAm) and simultaneous radical polymerization of AAm in an aqueous solution, (2) optimized the conditions for obtaining a phase-stable product, (3) studied the effect of the initial concentrations of Au and AAm on the morphology and structure of Au NPs, (4) obtained and characterized plasmonic films from the Au NPs-PAAm composite and after thermal removal of the polymer matrix. The methods of UV-visible and photon correlation spectroscopy, X-ray diffraction, synchronous thermal analysis, transmission and scanning electron microscopy were used in the work. Graphical abstract

Hybrid composites of gold nanoparticles (Au NPs) with polymer hydrogels are promising platforms for the development of new materials that can respond to external stimuli (chemical, physical, mechanical), reversibly absorb/release water and reagents, act as plasmonic sensors, and also as catalysts for photochemical processes and photothermal actuators of micromechanical processes. We proposed a one-step synthesis of a hybrid composite of Au NPs doped into polyacrylamide (PAAm) hydrogel by reducing HAuCl4 with acrylamide (AAm) and simultaneous radical polymerization of AAm, initiated by (NH4)2S2O8, in the aqueous solution. The influence of initial concentrations of 0.26–10 mM Au and 0.1–1 M AAm on the morphology and structure of Au NPs, as well as on the phase stability of the products, was studied. At concentrations of 3 mM Au, 1 M AAm and 1.2 mM (NH4)2S2O8, а temperature of 60 °C and a heating time of 6 h, a stable product with a clearly defined SPR band with a maximum at 552 nm was obtained. It contained polycrystalline Au NPs in the form of spheroids, cuboctahedra, and rods up to 100 nm size. The product was used to obtain plasmonic films of Au NPs-PAAm composite after drying at 100 °C and gold after thermal removal of the polymer matrix at 550 °C.The work used UV-visible and photon correlation spectroscopy, X-ray diffraction, synchronous thermal analysis, transmission and scanning electron microscopy.

Due to enhanced high-temperature stability, zirconia-stabilized alumina is widely used as a support of three-way catalysts. The addition of barium oxide is known to improve the catalytic performance of the composition. In order to go in-depth about the effects of BaO addition, a series of samples was prepared using nitrates and complex salts as a precursor. The interaction of BaO with alumina was found to change dramatically the metal-support interaction of the latter with metals. Thus, the presence of BaO resulted in the sintering of Pd with the formation of agglomerated Pd0 species, which explains a lower activity in CO oxidation of the BaO-doped samples after thermal treatment. Contrarily, the addition of barium nitrate showed a positive effect, inhibiting the collapse of the porous structure of the support, which was the most crucial and accompanied by the formation of the α-Al2O3 phase when no barium nitrate was added.

Multicomponent metal systems attract growing interest today, especially as catalysts for various processes. In the present work, a series of [CoFeNi]Pdx alloys (equal atomic content of base metals) doped with palladium in the amount of 0-10 at.% were synthesized via thermolysis of multicomponent precursors. The resulting [CoFeNi]Pdx alloys were found to be single-phase solid solutions with a fcc structure represented by agglomerates of grains fused. The performance of the alloys was explored in a mixture of saturated hydrocarbons (C2-C4) within the temperature range of 600-675 degrees C. As a result of interaction with the reaction mixture, spontaneous disintegration of the alloys containing above 2 at.% Pd occurs with the formation of dispersed particles responsible for the catalytic growth of carbon nanofibers (CNF). The dependence of the productivity of the [CoFeNi]Pdx alloys towards CNFs on the x parameter was studied. The highest CNF yield (YC = 25-46 g/gcat, 30 min) was achieved at an optimal Pd concentration of 8 at.% within the entire temperature range. According to TEM and EDX data, regardless of the reaction temperature and Pd concentration in the alloy, the catalyst particles have the same composition as defined at the synthesis of the alloys. The resulting CoFeNiPd@CNF composite can be considered as a catalyst for other heterogeneous catalysis processes.

In the present work, alumina-supported trimetallic Pd-Rh-Ru catalysts were synthesized and studied in comparison with the bimetallic Pd-Rh reference sample. The alloy nanoparticles were formed on the surface of the alumina support by thermolysis of the complex salts [Rh(NH3)5Cl][Pd(NO2)4] and [Rh(NH3)5Cl]0.5[Ru(NH3)5Cl]0.5[Pd(NO2)4], preliminary deposited via an incipient wet impregnation method. The influence of the conditions of the thermolysis process on the phase composition of the final products and the size of the trimetallic particles was established. Thus, nanoscale trimetallic (Rh-Ru-Pd) alloy particles of a given composition were obtained. The catalytic performance of the alumina-supported samples was examined in a CO oxidation reaction under prompt thermal aging conditions. It was ascertained that the addition of ruthenium only improves both the initial activity and thermal stability of the catalytic system. The state of each metal in the alloy nanoparticles was characterized by diffuse reflectance UV-vis spectroscopy and X-ray photoelectron spectroscopy.

Heteronuclear coordination compounds of d-metals are effective precursors for the production of bimetallic nanoalloys (Plyusnin et al., 2022) [1], which, in turn, are widely used in catalysis. Catalysts based on Rh and Cu, as well as Rh and Zn, are highly active in the process of steam reforming of hydrocarbons. Double oxalates of Rh with Cu and Rh with Zn with the general formula [(C2O4)(H2O)2Rh- (mu-C2O4)-M(H2O)2-(mu-C2O4)-Rh (H2O)2(C2O4)]& sdot;6H2O (M = Cu, Zn) are synthesized and structurally characterized. According to thermogravimetric analysis, the complexes completely decompose in He and H2 atmospheres already at 300 degrees C with the formation of the corresponding nanoalloys in the Cu-Rh and Zn-Rh systems. Calcination in an O2 atmosphere leads to the formation of a mixed oxide with a spinel structure. The Cu-Rh/Ce0.75Zr0.25O2 and Zn-Rh/ Ce0.75Zr0.25O2 catalysts were prepared by impregnation by moisture capacity on a porous support followed by calcination in a hydrogen atmosphere. The obtained catalysts were tested in propane steam reforming for hydrogen production at 300-480 degrees C and WHSV = 10 000-40 000 cm3 h- 1 center dot gcat- 1. At these conditions the Cu-Rh/ Ce0.75Zr0.25O2 and Zn-Rh/Ce0.75Zr0.25O2 catalysts demonstrated high selectivity for hydrogen (more than 70 %) compared to the monometallic catalyst Rh/Ce0.75Zr0.25O2 (less than 60%). Bimetallic catalysts make it possible to increase hydrogen productivity by reducing the reaction rate of methanation of carbon oxides, which is achieved due to the presence of Cu and Zn in the catalyst structure.

In this research, a self-dispersing 92Ni-4Mo-4W catalyst showing high productivity towards the H 2-assisted synthesis of turbostratic carbon nanofibers was proposed. The effect of reaction temperature on the efficiency of 92Ni-4Mo-4W alloy in the decomposition of trichloroethylene was studied. It was found that in the temperature range of 580-620 degrees C, the most rapid destruction of the initial alloy followed by the growth of carbon material is realized. This is confirmed by the minimum induction period (9-11 min) and the maximum carbon yield (95-107 g/g cat ). As revealed, the catalytically active particles of submicron size contain uniformly distributed Ni, Mo, and W. It is demonstrated that the decomposition of trichloroethylene over the 92Ni-4Mo-4W catalyst results in the formation of a turbostratic carbon material with a segmented structure, containing a minimum quantity of amorphous carbon and possessing high textural characteristics (specific surface area of 330-410 m 2 /g; pore volume of 0.48-0.58 cm 3 /g).

The samples of the C-Y2O3 compounds doped with photoluminescence activators Tb3+ and Eu3+ with the concentration of 3 and 3.5 mol

Using the method of reductive thermolysis of two-component precursors, a series of microdispersed alloys Ni1–xRux containing up to 10 at