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Abstract The equilibrium Cu–Pd phase diagram has been experimentally reinvestigated in the 300–680 °C temperature region by powder XRD involving a high-temperature technique. To reduce the annealing time needed for the system to attain the equilibrium state, nanosized specimens with a characteristic crystallite size of 5–15 nm were used initially. All previously reported phases, i.e., a disordered face-centered cubic solid solution Cu 1-x Pd x (A1), a one-dimensional long-period superlattice structure Cu 21 Pd 7 (1D–LPS), intermetallic compounds Cu 3 Pd (L1 2) and CuPd (B2), except a two-dimensional long-period superlattice structure (2D–LPS), could be confirmed. Homogeneity ranges of all solid phases existing in the Cu–Pd system were determined at distinct temperatures. The largest deviation of the solubility limits was observed for the Pd-rich boundary of the Cu 3 Pd region (25–30 at.% Pd) and the Cu-rich boundary of the Cu 1-x Pd x region in the compositional range >55 at.% Pd. Based on the present experimental results, the constitutional Cu–Pd diagram was modified. Graphical abstract Image 1 Highlights • The Cu–Pd phase diagram has been experimentally reinvestigated. • Ordering occurs through the nucleation and growth mechanism. • The disorder → order transformations near the critical temperature proceeds rapidly. • Proposed the corrected phase diagram of the Cu–Pd system. [ABSTRACT FROM AUTHOR]

The Pd–Rh phase diagram has been reinvestigated in the subsolidus region using X-ray diffraction, scanning and transmission electron microscopy. The true equilibrium at the miscibility boundary was achieved with the two-way approach. Nanosized powders of metastable solid solutions and two-phase palladium–rhodium mixtures were used to shorten the time required to equilibrate the system. The initial samples were prepared by decomposition of coordination compounds [Pd(NH 3 ) 2 Cl 2 ], [Rh(NH 3 ) 5 Cl]Cl 2 , [Pd(NH 3 ) 4 ] 3 [Rh(NO 2 ) 6 ] 2 and [Pd(NH 3 ) 4 ][Rh(NH 3 )(NO 2 ) 5 ]. The obtained phase diagram exhibits miscibility gap wider than generally accepted with the critical point of solubility at 58 at.% Rh and 820 °C. [ABSTRACT FROM AUTHOR]

13 C-enriched fine-grained graphitic material has been studied towards its potential for chemical and electrochemical applications. The structural and morphological modification of the material as results of pressure-assisted thermal treatment and gaseous BrF 3 and/or Br 2 room-temperature treatments has been investigated using a combination of the characterization tools: electron microscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron and near edge X-ray absorption fine structure spectroscopy, solid state nuclear magnetic resonance (NMR) spectroscopy and magnetic susceptibility measurements. It has been found that the starting material represents graphitized carbon with oxygen containing defects. The evidence of distorted sp 2 hybridization of carbon was found in the Raman and the 13 C NMR spectra. Under high pressure and temperature, some initially open graphitic edges are coupled that causes decreasing specific surface area and mean in-plane size of crystallites, and, generally, a higher degree of disorder. The Br 2 treatment improves the material structure due to removal of tiny graphitic flakes and oxygenated carbon groups. The use of BrF 3 results, in addition, in partial fluorination of graphitic material. Electrochemical characteristics along with a high degree of 13 C isotope enrichment enable the application of these graphitic materials in operando studies using methods sensitive to 13 C isotope, such as NMR. [ABSTRACT FROM AUTHOR]

Abstract: Calcium tartrate doped with Ni and/or Co has been used as a catalyst source in the chemical vapor deposition synthesis of carbon nanotubes (CNTs). Thermolysis of doped calcium tartrate in an inert atmosphere was shown to yield Ni, Co or Ni–Co nanoparticles ∼6nm in diameter dispersed in a calcium oxide matrix. The CNT synthesis was carried out by ethanol vapor decomposition at 800°C. The structure of the products was characterized by transmission electron microscopy and Raman spectroscopy. It was found that Ni nanoparticles embedded in CaO provide the narrowest diameter distribution of CNTs, while the bimetallic Ni–Co catalyst allows the formation of the thinnest CNTs with the outer diameter of ∼2nm. This type of CNT is more likely to be responsible for the lowest value of the turn-on field (∼1.8V/μm) for the emission current detected for the latter sample. [Copyright &y& Elsevier]

• Composition of graphite fluoride C 2 F x is controlled by changing the ratio BrF 3 /Br 2 in reaction. • The size of sp2 carbon regions increases with the decrease of x in C 2 F x. • Replacement of guest molecules in C 2 F x has little effect on the matrix properties. • Br 2 guests in C 2 F x are difficultly substitutable for CH 3 CN when x < 0.5. The interaction of graphite with a gaseous mixture of BrF 3 and Br 2 at room temperature produced fluorinated graphite intercalation compounds with bromine. By changing the concentration of BrF 3 in Br 2 from 6.2 to 2.9 % we were able to obtain matrices of fluorinated graphene layers (C 2 F x) n with x = 0.76, 0.66, 0.35, 0.25. It was shown that bromine was completely replaced by acetonitrile in the (C 2 F x) n with x > 0.6, while two types of guests (CH 3 CN and Br 2) were present between the layers with the lower fluorine loading. The Van der Waals forces hold CH 3 CN molecules in the (C 2 F x) n host. The interaction of Br 2 molecules with sp2 -carbon regions remained in the C 2 F x layers has donor-acceptor type. The models of guest molecules packing in host matrices (C 2 F x) n are considered using the data on the stoichiometry and X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

Abstract Hot pressing is one of the promising routes for graphitization of carbon materials. In the present work, high-pressure high-temperature behaviour of 13C-enriched fine-grained graphitic material has been studied by using a set of experimental tools such as scanning electron microscopy, Raman scattering, X-ray diffraction, X-ray photoelectron and near-edge X-ray absorption fine structure spectroscopies, and solid-state nuclear magnetic resonance (NMR) spectroscopy. The material has been annealed at a temperature of 1200 or 1500 °C using a stabilizing pressure of 5 GPa. It shown, that addition of small amount of water during the annealing at 1200 °C results in a better local atomic ordering of carbon material and increases the hydrocarbon fraction. Well-ordered graphite crystals enriched with 13C isotope are formed on the surface of nickel ampule at 1500 °C. An increase in processing time from 2 to 15 h decreases the defect density and improves the graphitization level of the material. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Electrochemical performance of MoS 2 /graphene materials in Li-ion batteries is strongly dependent on the structure of individual components and their coupling in the hybrid. We present a comparative study of the materials produced by annealing of amorphous MoS 3 deposited on the surface of multilayer graphene flakes at 500 °C, 800 °C, and 1000 °C in vacuum. X-ray photoelectron spectroscopy confirmed a transformation of MoS 3 to MoS 2 at these conditions. High-resolution transmission electron microscopy and Raman scattering showed a growth of in-plane size of MoS 2 nanocrystals with a raise of annealing temperature. Electrochemical tests detected a gradual decrease of the specific capacity of the MoS 2 /graphene materials prepared at 500 and 800 °C and a stable performance for the material synthesized at 1000 °C even at high current densities. Based on the initial discharge-charge profiles, we associate this effect with in-plane size of MoS 2 nanocrystals, which should decompose more easily when the size is small, due to the interaction of lithium with edge sulfur atoms. [ABSTRACT FROM AUTHOR]

Various manifestations of the exchange interaction effects in magnetization curves of the CoPt nanostructured particles are demonstrated and discussed. The inter-grain exchange constant A in the sponge-like agglomerates of crystallites is estimated as A =(7±1) pJ/m from the approach magnetization to saturation curves that is in good agreement with A =(6.6±0.5) pJ/m obtained from Bloch T 3/2 law. The fractal dimensionality of the exchange coupled crystallite system in the porous media of the disordered CoPt alloy d =(2.60±0.18) was estimated from the approach magnetization to saturation curve. Coercive force decreases with temperature as H c ~ T 3/2 which is assumed to be a consequence of the magnetic anisotropy energy reduction due to the thermal spin wave excitations in the investigated CoPt particles. [ABSTRACT FROM AUTHOR]

Surface combustion synthesis was applied as a coating technique to prepare the fiberglass systems with supported oxide layer. Effect of the dopant's nature (Co 3 O 4 , Mn 3 O 4 ) on catalytic activity of the supported copper-ceria samples was studied. Catalyst samples were characterized by various physicochemical methods. Active components exist on surface of support in three different states: large agglomerates; small particles and thin oxide film. The additive is found to be in highly disperse state. Catalytic activity of modified CuO–CeO 2 samples has been tested in CO oxidation. It was established that the catalytic performance is to be directly determined by the nature of dopant and the way it interacts with CuO phase. [ABSTRACT FROM AUTHOR]

Here, we show for the first time a catalytic chemical vapor deposition (CCVD) synthesis of carbon nanotubes (CNTs) using polyoxomolybdate clusters Mo 12 O 28 (μ 2 -OH) 12 {Ni(H 2 O) 3 } 4 and Mo 12 O 28 (μ 2 -OH) 12 {Co(H 2 O) 3 } 4 as a source of catalyst nanoparticles. X-ray diffraction analyses indicated that the products of thermal decomposition of the clusters contain NiMoO 4 and CoMoO 4 phases, which are converted into Ni–Mo and Co–Mo alloys at 900 °C in hydrogen environment. High-resolution transmission electron microscopy in combination with energy-dispersive X-ray spectroscopy confirmed the CNT growth from bimetallic nanoparticles. Synergism between two metals in an alloy resulted in large-scale production of non-bundled few-walled CNTs with narrow diameter distribution and high quality. [ABSTRACT FROM AUTHOR]

[Display omitted] • Brominated carbon nanohorns (CNHs) contains covalently bonded and intercalated bromine. • Pre-oxidation of CNHs opens their inner cavity and increases intercalated bromine. • Brominated open CNHs show outstanding electrochemical capacities in SIBs. • Bromine groups promote the adsorption of Na+ ions. Carbon nanohorns (CNHs) have low layering, internal cavities, a large number of defects and these structural features are important for the effective accumulation of sodium ions. Since nanohorns can be easily modified, this opens up possibilities for controlling their properties. In this work, initial CNHs and CNHs opened by thermal oxidation in the air were successfully brominated to bromine concentrations of 7 and 5 at%, respectively. Cyclic voltammetry curves revealed two peaks at potentials of 1.4 and 2.1 V vs Na/Na+ and the related processes contributed to the capacity of the brominated samples. Density functional theory calculations showed that the peaks correspond to reversible adsorption/desorption of Na+ ions on the surface of CNHs near the brominated tips and the adsorbed bromine molecules. As a result, brominated open CNHs with a large amount of Br 2 had the highest specific capacity of 129–62 mAh g−1 at 0.1–2 A g−1 as compared to the corresponding values of 117–41 mAh g−1 for the initial CNHs. Our results show that the bromination of carbon materials, pretreated for controlling the introduction of certain forms of bromine, is a way to improve their performance in sodium-ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: A complex salt [Ru(NH3)5Cl][Cu(C2O4)2H2O]—the precursor of nanoalloys combining ruthenium and copper was prepared. It crystallizes in the monoclinic space group P21/n. Thermal properties of the prepared salt were examined in different atmospheres (helium, hydrogen, oxygen). Thermal decomposition of the precursor in inert atmosphere was thoroughly examined and the intermediate products were characterized. Experimental conditions for preparation of copper-rich (up to 12at% of copper) metastable solid solution Cu x Ru1−x (based on Ru structure) were optimized, what is in sharp contrast to the bimetallic miscibility gap known for the bulk counterparts in a wide composition range. Catalytic properties of copper–ruthenium oxide composite were tested in catalytic oxidation of CO. [Copyright &y& Elsevier]

Abstract: Two octahedral nickel complexes namely Ni(pda)(hfac)2 and Ni(pda)(thd)2 (pda—1,3-diaminopropane, hfac—1,1,1,5,5,5-hexafluoro-2,4-pentanedionato (−), thd—2,2,6,6-tetramethyl-3,5-heptanedionato (−)) were tested in a Metal-Organic Chemical Vapor Deposition (MOCVD) process. Based on density functional theory (DFT) calculations, the thermodynamic stability of molecules in the gas phase was estimated. The intramolecular bond was found in case of complex Ni(pda)(hfac)2. The different fragmentation mechanisms of complexes in the gas phase were examined by double focusing sector (DFS) mass spectrometry. According to TG/DTA analyses and P/T measurements compounds have good volatility. Deposition conditions resulting in one phase Ni films were established. Films compositions and structures were confirmed by XRD, EXAFS, XPS, and SEM. According to XRD and SEM, the average crystallite sizes and thicknesses of films deposited from Ni(pda)(hfac)2 were 12–34nm and 135–320nm, whereas from Ni(pda)(thd)2 they were 10–24nm and 100–380nm, respectively. The dependences of films thicknesses as a function of substrate temperatures have shown that complex Ni(pda)(hfac)2 is more stable in the gas phase than Ni(pda)(thd)2. [Copyright &y& Elsevier]

Perforation of graphite is carried out by treating the graphite oxide with a boiling mineral acid H2SO4 or H3PO4. High-resolution transmission electron microscopy shows formation of a large number of vacancy defects (holes) in the graphene sheets, which are caused more likely by the CO2 liberation during the reduction process. The characteristic size of the holes is about 2 nm. The obtained materials are comparatively examined by X-ray diffraction, Raman and IR-absorption spectroscopy, X-ray photoelectron and near-edge X-ray absorption fine structure spectroscopy. It is found that the products obtained using a strong acid H2SO4 and a weak acid H3PO4 are different in the concentration and electronic state of oxygen and the mean distance between defects. [ABSTRACT FROM AUTHOR]

Abstract: Bimetallic alumina and ceria supported Pt–Co catalysts were prepared via the decomposition of a [Co(H2O)6][Pt(NO2)4]·2H2O double complex salt. Catalysts were tested in CO preferential oxidation (PROX). PtCo/Al2O3 catalyst exhibited high activity and selectivity. It provided the CO conversion higher than 80% and selectivity above 60% in the temperature interval 90–165°C at WHSV of 260,000cm3 g−1 h−1 and O2/CO ratio of 0.6. XRD and TEM analysis indicated the formation of a platinum-rich Pt–Co alloy nanoparticles supported over alumina surface. [Copyright &y& Elsevier]

Abstract: Ni(pda)(hfac)2 (1) and Ni(pda)(thd)2 ( 2 ) were synthesized and studied as new potential precursors for Metal-Organic Chemical Vapor Deposition (MOCVD). Both crystal structures have been determined by single-crystal X-ray diffraction: compounds are triclinic, space group P, compound (1) has crystal parameters a = 8.5379(4), b = 10.4994(4), c = 11.4186(4) Å, α = 112.091(1), β = 98.385(1), γ = 92.937(1); compound (2) has crystal parameters a = 9.4622(3), b = 11.8986(5), c = 14.1575(6) Å, α = 71.600(1), β = 71.279(1), γ = 88.505(1). These are neutral complexes. Thermal gravimetric analyses (TG/DTA) have shown that both complexes sublime practically without decomposition. Thermodynamic parameters (Δ mpH, Δ mpS) and T mp of the complexes were determined by differential scanning calorimetry. MOCVD test experiments were carried out at lower pressure using Ni(pda)(hfac)2(1) and Ni(pda)(thd)2 ( 2 ) as precursors. The films were grown on Ta/Si substrate and investigated by XRD and SEM. [Copyright &y& Elsevier]

Abstract: Nitrogen-doped carbon (CN x ) nanotubes have been synthesized by acetonitrile vapor decomposition over catalyst nanoparticles produced in the result of thermolysis of solid solutions of Fe and Ni bimaleates. X-ray photoelectron spectroscopy revealed the nitrogen content in CN x nanotubes grows from 0.4 to 1.2at%, when Ni portion in catalyst increases. Nitrogen doping level of sample produced using bimaleates of Fe and Ni taken in a ratio of 7:3 is deviated from this dependence due to formation of two phases of metallic catalyst. N 1s-edge X-ray absorption spectra of samples showed three peaks, which by results of quantum-chemical calculation on nitrogen-containing carbon nanotube (CNT) model were assigned to pyridinic, graphitic, and molecular forms of nitrogen. Measurements of current–voltage characteristics of the samples found the electron emission threshold is reduced with amount of nitrogen incorporated into CN x nanotubes. [Copyright &y& Elsevier]

Abstract: Double complex salts [M(NH3)4][M′(Ox)2(H2O)2]·2H2O (M=Pd, Pt, M′=Ni, Zn) were synthesized by combination of solutions containing corresponding cations [M(NH3)4]2+ and anions [M′(Ox)2(H2O)2]2−. The salts obtained were characterized by IR spectroscopy, thermal analysis, powder and single crystal X-ray diffraction. The prepared compounds are isostructural and crystallize in the orthorhombic crystal system (space group I222, Z =2). Thermal decomposition of the salts in helium or hydrogen atmosphere at 200–400°C results in formation of nano-sized bimetallic powders. Depending on the phase diagram of the respective bimetallic system and temperature conditions, they can be single phase or multiphase products. In particular, thermal decomposition of double complex salts [M(NH3)4][Zn(Ox)2(H2O)2]·2H2O (M=Pd, Pt) results in formation of PdZn and PtZn intermetallic compounds, correspondingly. Decomposition of [Pd(NH3)4][Ni(Ox)2(H2O)2]·2H2O affords a disordered solid solution Pd0.5Ni0.5. Disordered Pt0.5Ni0.5 was obtained from [Pt(NH3)4][Ni(Ox)2(H2O)2]·2H2O in helium atmosphere, while in hydrogen atmosphere – a two-phase mixture of disordered Pt0.5Ni0.5 and ordered PtNi. In all cases crystallite sizes of bimetallic particles varied within 50–250Å. [Copyright &y& Elsevier]

Abstract: Dimethylgold(III) carboxylates of general formula [(CH3)2Au(OOCR)]2 (R = methyl, or tert-butyl) were synthesized with high yields. The products are stable to air and moisture and soluble in most common organic solvents. An elemental analysis, X-ray, mass-spectrometry, IR, and 1H NMR spectroscopy were used for characterization of prepared compounds. The thermal properties of gold compounds in solid state were investigated by the TG method. The temperature dependences of saturated vapor pressure were studied by the Knudsen effusion method. The thermodynamic parameters of the sublimation process ▵H°Т and ▵S°Т were calculated. Thermal decomposition of the vapor of gold complexes was studied by means of high temperature mass spectrometry in vacuum, and by-products of decomposition were determined. The CVD processes of gold film deposition were carried out at atmospheric pressure. Silicon was used as a substrate. The evaporation temperature was varied from 95 to 120 °C. The substrate temperature was 210 °C. The gold film samples were investigated by means of SEM and X-ray diffraction analysis. [Copyright &y& Elsevier]

Synthesis and investigation of a binary complex salt [Cr(NH3)5Cl][PdCl4]·H2O is reported. The compound is isostructural with [Rh(NH3)5Cl][PdCl4]·H2O studied earlier; it was characterized by element analysis and powder and single crystal X-ray diffraction. Crystal data for H17Cl5N5OPdCr:a= 7.8668(12) Å,b= 10.9703(16) Å,c= 16.048(2) Å, ß = 102.469(3)°, space groupP21/c,Z=4,V=1352.3(3)Å3,dcalc = 2.155 g/cm3. [ABSTRACT FROM AUTHOR]

• The counter precipitation method was used to synthesise composite catalysts Pd/CeO 2 -SnO 2 • The calcination at 800−1000 °C results in strong enhancement of low-temperature CO oxidation • Pd/CeO 2 -SnO 2 catalysts are thermally stable up 1100 °C due to formation of nanoheterogeneous structure • SnO 2 nanoparticles serve as stabilisers of Pd x Ce 1-x O 2- δ nanoparticles • Pd/CeO 2 -SnO 2 catalysts are characterized by high water resistance in CO oxidation In this work, the counter precipitation method was used to synthesise Pd/CeO 2 -SnO 2 catalysts, which possess excellent low-temperature activity and high thermal stability. It was revealed that calcination of Pd/CeO 2 -SnO 2 catalysts at 800−1000 °C induces significant growth of catalytic activity in CO oxidation at T<150 °C. This effect of thermal activation for Pd/CeO 2 -SnO 2 catalysts was enhanced when water was admitted to the reaction mixture. In the presence of water the T 50 value for the Pd/CeO 2 -SnO 2 catalyst calcined at 900 °C becomes 45 °C lower than for the Pd/CeO 2 catalyst. It was found that calcination of the catalysts at T<600 °C leads to the formation of solid solutions based on the fluorite and rutile structures. As the calcination temperature is raised above 600 °C, the solid solutions decompose with formation of catalytically active Pd x Ce 1-x O 2- δ dispersed phase on the surface of SnO 2 nanoparticles. The formed nanoheterogeneous structure provides both high thermal stability and high water resistance of Pd/CeO 2 -SnO 2 catalysts. [ABSTRACT FROM AUTHOR]

Abstract: HfO2 layers were grown on silicon by metalorganic chemical vapor deposition using (C5H5)2Hf(CH3)2, (C5H5)2Hf(N(C2H5)2)2 and Hf(dpm)4 as volatile precursors and were characterized by IR, XP, ED-spectroscopy, X-ray diffraction, ellipsometry and electrophysical methods. The films were shown to consist of monoclinic HfO2 and to contain hafnium silicide and silicate at the HfO2/Si interface. The presence of hafnium silicide was attributed to oxygen deficiency induced by argon ion sputtering of the film during XPS analysis. Hafnium silicate was formed as a result of the reaction between hafnia and silicon oxides during annealing. Current–voltage and capacitance–voltage measurements on Al/HfO2/Si test structures were used to determine the dielectric permittivity and electrical resistivity of the films: k=15–20, ρ=1015 Ωcm. [Copyright &y& Elsevier]