RHENIUM CARBIDES PREPARED BY THERMOBARIC TREATMENT OF NANOSIZED PRECURSORS

PACS 61.05.cp; 61.50.Ks The products of thermobaric treatment (P = 6 GPa; T = 1800 • C) of mechanical mixtures of nanosized rhenium powder and sibunit have been studied. The formation of high-temperature phases with composition Re 2 C has been revealed

First hexagonal close packed high-entropy alloy with outstanding stability under extreme conditions and electrocatalytic activity for methanol oxidation

High-entropy alloys containing 5 and 6 platinum group metals have been prepared by thermal decomposition of single-source precursors non requiring high temperature or mechanical alloying. The prepared Ir0.19Os0.22Re0.21Rh0.20Ru0.19 alloy is the first example of a single-phase hexagonal high-entropy alloy. Heat treatment up to 1500 K and compression up to 45 GPa do not result in phase changes, a record temperature and pressure stability for a single-phase high-entropy alloy. The alloys show pronounced electrocatalytic activity in methanol oxidation, which opens a route for the use of high-entropy alloys as materials for sustainable energy conversion

Thin films of unsubstituted and fluorinated palladium phthalocyanines: structure and sensor response toward ammonia and hydrogen

In the present work, we study and compare the structure and sensing properties of thin films of unsubstituted palladium phthalocyanine (PdPc) and hexadecafluorosubstituted palladium phthalocyanine (PdPcF16). Thin films of PdPc and PdPcF16 were obtained by the method of organic molecular beam deposition and their structure was studied using UV-visible spectroscopy, X-ray diffraction and atomic force microscopy techniques. The electrical sensor response of PdPc films toward ammonia and hydrogen was investigated and compared with that of PdPcF16 films. The nature of interaction between the phthalocyanines films and some gaseous analyte molecules has been clarified using Quantum chemical (DFT) calculations

Effect of fluorosubstitution on the structure of single crystals, thin films and spectral properties of palladium phthalocyanines

In this work, the crystalline structure of single crystals grown by vacuum sublimation of unsubstituted palladium phthalocyanines (PdPc), its tetrafluorinated (PdPcF4) and hexadecafluorinated (PdPcF16) derivatives have been investigated using X-ray diffraction measurements. Two crystalline phases have been identified for PdPc; the molecules in both phases crystallize in stacks with herringbone arrangement in the monoclinic space groups (C2/c for -PdPc; P21/n for -PdPc). Both PdPcF4 and PdPcF16 crystallize in the triclinic P-1 space group, forming stacks of molecules in columnar arrangement with molecules in adjacent columns are aligned parallel to one another. X-ray diffraction measurements have also been used to elucidate the structural features and molecular orientation of thin films of PdPc, PdPcF4 and PdPcF16, grown by organic molecular beam deposition at different substrate temperatures. The effect of fluorosubstitution on UV-visible optical absorption and vibrational spectra of palladium phthalocyanine derivatives is also discussed

Ir–Re binary alloys under extreme conditions and their electrocatalytic activity in methanol oxidation

The formation of the hcp-Ir0.70Re0.30 alloy from the single-source precursor (NH4)2[Ir0.70Re0.30Cl6] upon heating in hydrogen atmosphere can be associated with the formation of two intermediates: a crystalline iridium-based intermediate and a fcc-structured alloy. Ir–Re alloys show lower thermal expansion coefficients and smaller compressibility in comparison with individual metals. The high-temperature high-pressure treatment of hcp-Ir0.70Re0.30 alloy enable us to probe the Ir–Re pressure dependent phase diagram. The miscibility gap between hcp and fcc alloys slightly shifts towards the rhenium side below 4 GPa. Above 4 GPa, the miscibility gap does not drift with pressure and narrows with compression. The electrocatalytic activity of Ir–Re alloys has been tested for methanol oxidation in acidic water solution. Ir–Re alloys show higher electrocatalytic activity in comparison with pure Ir and Re, which makes them perspective candidates for fuel cells application. The highest electrocatalytic activity has been obtained for the two-phase Ir0.85Re0.15 composition

Effect of fluorosubstitution on the structure of single crystals, Effect of fluorosubstitution on the structure of single crystals,thin films and spectral properties of palladium phthalocyanines

In this work, the crystalline structure of single crystals grown by vacuum sublimation of unsubstituted palladium phthalocyanines (PdPc), its tetrafluorinated (PdPcF4) and hexadecafluorinated (PdPcF16) derivatives have been investigated using X-ray diffraction measurements. Two crystalline phases have been identified for PdPc; the molecules in both phases crystallize in stacks with herringbone arrangement in the monoclinic space groups (C2/c for -PdPc; P21/n for -PdPc). Both PdPcF4 and PdPcF16 crystallize in the triclinic P-1 space group, forming stacks of molecules in columnar arrangement with molecules in adjacent columns are aligned parallel to one another. X-ray diffraction measurements have also been used to elucidate the structural features and molecular orientation of thin films of PdPc, PdPcF4 and PdPcF16, grown by organic molecular beam deposition at different substrate temperatures. The effect of fluorosubstitution on UV-visible optical absorption and vibrational spectra of palladium phthalocyanine derivatives is also discussed

О фосфатных производных соли Чугаева

Pt(IV) chloropentaammine phosphate was studied in details using IR and UV-Vis spectroscopy, X-ray powder diffraction, differential thermal and elemental analysis. Crystal structure of the complex was solved from powder diffraction data. 195Pt and 14N NMR spectra of [Pt(NH3)5Cl]3+cation were obtained and interpreted for the first time.С использованием методов ИК и электронной спектроскопии, РФА, ДТА и элементного анализа детально изучены фосфорнокислые соли хлоропентаммина Pt(IV). Разрешена кристаллическая структура солей. Впервые для хлоропентаммина Pt(IV) получены спектры ЯМР на ядрах 195Pt и 14N

Thin Layers XRD Study Technique on an Example of Cobalt Tetrafluoro Phthalocyanine

Thin layers X-ray diffraction study technique utilizing single-crystal X-ray diffractometer equipped with microfocus X-ray tube is described. It is shown that the layers of the tetra-fluorinated cobalt phthalocyanine (CoPcF₄), deposited by thermal evaporation in vacuum on a polished surface of the substrate (glass, quartz), have a highly oriented polycrystalline structure. All the crystallites have the (00l) plane oriented along the surface of the substrate. CoPcF₄ X-ray diffraction pattern indexing was conducted and unit cell parameters were determined. It is shown that crystal phase of both polycrystalline powder and thin layers of CoPcF₄ are isostructural to that of α -CoPc

Thin layers XRD study technique on an example of cobalt tetrafluoro phthalocyanine

Thin layers X-ray diffraction study technique utilizing single-crystal X-ray diffractometer equipped with microfocus X-ray tube is described. It is shown that the layers of the tetra-fluorinated cobalt phthalocyanine (CoPcF₄), deposited by thermal evaporation in vacuum on a polished surface of the substrate (glass, quartz), have a highly oriented polycrystalline structure. All the crystallites have the (00l) plane oriented along the surface of the substrate. CoPcF₄ X-ray diffraction pattern indexing was conducted and unit cell parameters were determined. It is shown that crystal phase of both polycrystalline powder and thin layers of CoPcF₄ are isostructural to that of α -CoPc

Thin Layers XRD Study Technique on an Example of Cobalt Tetrafluoro Phthalocyanine

Thin layers X-ray diffraction study technique utilizing single-crystal X-ray diffractometer equipped with microfocus X-ray tube is described. It is shown that the layers of the tetra-fluorinated cobalt phthalocyanine (CoPcF4), deposited by thermal evaporation in vacuum on a polished surface of the substrate (glass, quartz), have a highly oriented polycrystalline structure. All the crystallites have the (00l) plane oriented along the surface of the substrate. CoPcF4 X-ray diffraction pattern indexing was conducted and unit cell parameters were determined. It is shown that crystal phase of both polycrystalline powder and thin layers of CoPcF4 are isostructural to that of α-CoPc