Browse
Submit Data
Databases
API
Help

Dataset Information

26 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Rare-earth metal catalysts for high-pressure synthesis of rare diamonds.

ABSTRACT: The combination of the unique properties of diamond and the prospects for its high-technology applications urges the search for new solvents-catalysts for the synthesis of diamonds with rare and unusual properties. Here we report the synthesis of diamond from melts of 15 rare-earth metals (REM) at 7.8 GPa and 1800-2100 °C. The boundary conditions for diamond crystallization and the optimal parameters for single crystal diamond synthesis are determined. Depending on the REM catalyst, diamond crystallizes in the form of cube-octahedrons, octahedrons and specific crystals bound by tetragon-trioctahedron and trigon-trioctahedron faces. The synthesized diamonds are nitrogen-free and belong to the rare type II, indicating that the rare-earth metals act as both solvent-catalysts and nitrogen getters. It is found that the REM catalysts enable synthesis of diamond doped with group IV elements with formation of impurity-vacancy color centers, promising for the emerging quantum technologies. Our study demonstrates a new field of application of rare-earth metals.

SUBMITTER: Palyanov YN

PROVIDER: S-EPMC8055970 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Heteroatom-assisted olefin polymerization by rare-earth metal catalysts.

Project description:Heteroatom-functionalized polyolefins are of fundamental interest and practical importance. This has spurred investigations of the copolymerization of polar and nonpolar olefins. We report the first syndiospecific polymerization of a series of heteroatom-containing α-olefins and their copolymerization with ethylene catalyzed by half-sandwich rare-earth complexes. We have found that the interaction between a heteroatom in a functional α-olefin monomer and a rare-earth metal catalyst can significantly raise the olefin polymerization activity and thereby promote its copolymerization with ethylene. By using this heteroatom-assisted olefin polymerization (HOP) strategy, we have successfully synthesized a series of heteroatom (O, S, Se, N, and P)-functionalized polyolefins with high molecular weights and controllable functional monomer contents. The mechanistic aspect of the HOP process has been elucidated by computational studies. We expect that our findings will guide the design of new catalyst systems for the synthesis of various desired functional polyolefins.

| S-EPMC5521993 | biostudies-literature

Molten salt synthesis of carbon-supported Pt-rare earth metal nanoalloy catalysts for oxygen reduction reaction.

Project description:The synthesis of nano-sized alloys of Pt and rare earth (RE) metal catalysts has been a huge challenge due to a significantly large standard reduction potential difference of Pt and RE metals and the high synthesis temperature. Pt x Y/C catalysts with an average particle size of around 21 nm, were synthesized by mixing K2PtCl4 with Y2O3 (a molar ratio of Pt : Y = 1 : 1) with a carbon support in a molten LiCl-CaH2 system by a one-step molten salt synthesis method at 600 °C. The synthesis processes of the Pt x Y/C alloys are proposed as follows: Pt nanoparticles were first obtained by the reaction of K2PtCl4 and CaH2 at 210 °C, then Y ions were preferentially reduced on the Pt nanoparticle surface by the reduction of CaH2, followed by Pt x Y alloy formation in the molten LiCl-CaH2 system at 600 °C. Molten LiCl provides a strong reducing environment and lowers the formation temperature of alloys. Pt2Gd/C and Pt2La/C were also obtained with Gd2O3 and La2O3 as the starting raw materials, respectively by using the same process. When investigated as an electrocatalyst for the oxygen reduction reaction (ORR), the half-wave potentials of Pt x RE/Cs are all more positive than that of commercial Pt/C catalyst (e.g., 0.905 V for Pt x Y/C while 0.880 V for JM Pt/C), and the nano-sized Pt x Y/C alloy shows higher electrocatalytic activity toward the ORR and preferable catalytic durability with respect to JM Pt/C catalysts. This facile synthesis method provides an effective strategy for the preparation of Pt-RE based multicomponent nanoalloys, especially in large-scale production.

| S-EPMC8981501 | biostudies-literature

Synthesis of rare-earth metal and rare-earth metal-fluoride nanoparticles in ionic liquids and propylene carbonate.

Project description:Decomposition of rare-earth tris(N,N'-diisopropyl-2-methylamidinato)metal(III) complexes [RE{MeC(N(iPr)2)}3] (RE(amd)3; RE = Pr(III), Gd(III), Er(III)) and tris(2,2,6,6-tetramethyl-3,5-heptanedionato)europium(III) (Eu(dpm)3) induced by microwave heating in the ionic liquids (ILs) 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIm][NTf2]) and in propylene carbonate (PC) yield oxide-free rare-earth metal nanoparticles (RE-NPs) in [BMIm][NTf2] and PC for RE = Pr, Gd and Er or rare-earth metal-fluoride nanoparticles (REF3-NPs) in the fluoride-donating IL [BMIm][BF4] for RE = Pr, Eu, Gd and Er. The crystalline phases and the absence of significant oxide impurities in RE-NPs and REF3-NPs were verified by powder X-ray diffraction (PXRD), selected area electron diffraction (SAED) and high-resolution X-ray photoelectron spectroscopy (XPS). The size distributions of the nanoparticles were determined by transmission electron microscopy (TEM) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) to an average diameter of (11 ± 6) to (38 ± 17) nm for the REF3-NPs from [BMIm][BF4]. The RE-NPs from [BMIm][NTf2] or PC showed diameters of (1.5 ± 0.5) to (5 ± 1) nm. The characterization was completed by energy-dispersive X-ray spectroscopy (EDX).

| S-EPMC6036975 | biostudies-literature

Liquid-Phase Synthesis of Highly Reactive Rare-Earth Metal Nanoparticles.

Project description:The first liquid-phase synthesis of high-quality, small-sized rare-earth metal nanoparticles (1-3 nm)-ranging from lanthanum as one of the largest (187 pm) to scandium as the smallest (161 pm) rare-earth metal-is shown. Size, oxidation state, and reactivity of the nanoparticles are examined (e.g., electron microscopy, electron spectroscopy, X-ray absorption spectroscopy, selected reactions). Whereas the nanoparticles are highly reactive (e.g. in contact to air and water), they are chemically stable as THF suspensions and powders under inert conditions. The reactivity can be controlled to obtain inorganic and metal-organic compounds at room temperature.

| S-EPMC8361762 | biostudies-literature

Properties of Alkaline-Earth-Metal Polynitrogen Ternary Materials at High Pressure.

Project description:We report the formation of cubic and tetragonal BaSrN3 at 100 GPa using an ab initio structure search method. Pressure ramping to 0 GPa reveals a reaction pressure threshold of 4.92 and 7.23 GPa for the cubic and tetragonal BaSrN3, respectively. The cubic phase is stabilized by coulombic interaction between the ions. Meanwhile, tetragonal BaSrN3 is stabilized through an expansion of the d-orbital in Ba and Sr atoms that is compensated by delocalization of π-electrons in N through reduction of π overlap. Elastic properties analysis suggests that both phases are mechanically stable. The structures also have high melting points as predicted using an empirical model, and all imaginary modes vanishes at about 2000 K. These results have significant implication for the design of cleaner and environmentally friendly high energy density materials.

| S-EPMC7581264 | biostudies-literature

Synthesis and Thermal Decomposition of High-Entropy Layered Rare Earth Hydroxychlorides.

Project description:The synthesis of multicomponent and high-entropy compounds has become a rapidly developing field in advanced inorganic chemistry, making it possible to combine the properties of multiple elements in a single phase. This paper reports on the synthesis of a series of novel high-entropy layered rare earth hydroxychlorides, namely, (Sm,Eu,Gd,Y,Er)2(OH)5Cl, (Eu,Gd,Tb,Y,Er)2(OH)5Cl, (Eu,Gd,Dy,Y,Er)2(OH)5Cl, and (Eu,Gd,Y,Er,Yb)2(OH)5Cl, using a homogeneous hydrolysis technique under hydrothermal conditions. Elemental mapping proved the even distribution of rare earth elements, while luminescence spectroscopy confirmed efficient energy transfer between europium and other rare earth cations, thus providing additional evidence of the homogeneous distribution of rare earth elements within the crystal lattice. The average rare earth cation radii correlated linearly with the unit cell parameters (0.868 < R2 < 0.982) of the high-entropy layered rare earth hydroxychlorides. The thermal stability of the high-entropy layered rare earth hydroxychlorides was similar to that of individual hydroxychlorides and their binary solid solutions.

| S-EPMC11013826 | biostudies-literature

Emerging superconductivity rules in rare-earth and alkaline-earth metal hydrides.

Project description:Hydrides of alkaline-earth and rare-earth metals have garnered significant interest in high-temperature superconductor research due to their excellent electron-phonon coupling and high T c upon pressurization. This study explores the electronic structures and electron-phonon coupling of metal hydrides XHn (n = 4,6), where X includes Ca, Mg, Sc, and Y. The involvement of d-orbital electrons alters the Fermi surface, leading to saddle-point nesting and a charge density wave (CDW) phase transition, which opens the superconducting gap. For instance, in YH6, the exchange coupling between Y-4d and H-1s holes in the phonon softening region results in T c values up to 230 K. The study suggests that factors, such as the origin of the CDW order, hydrogen concentration, and d-orbital contributions are crucial to superconductivity. This work proposes a new rule for high T c superconductors, emphasizing the importance of double gaps and electron-phonon interactions at exchange coupling sites, and predicts potential high-quality superconductors among rare-earth hydrides.

| S-EPMC11342274 | biostudies-literature

Chemoselective single-site Earth-abundant metal catalysts at metal-organic framework nodes.

Project description:Earth-abundant metal catalysts are critically needed for sustainable chemical synthesis. Here we report a simple, cheap and effective strategy of producing novel earth-abundant metal catalysts at metal-organic framework (MOF) nodes for broad-scope organic transformations. The straightforward metalation of MOF secondary building units (SBUs) with cobalt and iron salts affords highly active and reusable single-site solid catalysts for a range of organic reactions, including chemoselective borylation, silylation and amination of benzylic C-H bonds, as well as hydrogenation and hydroboration of alkenes and ketones. Our structural, spectroscopic and kinetic studies suggest that chemoselective organic transformations occur on site-isolated, electron-deficient and coordinatively unsaturated metal centres at the SBUs via ?-bond metathesis pathways and as a result of the steric environment around the catalytic site. MOFs thus provide a novel platform for the development of highly active and affordable base metal catalysts for the sustainable synthesis of fine chemicals.

| S-EPMC5013626 | biostudies-literature

Chemical looping of metal nitride catalysts: low-pressure ammonia synthesis for energy storage.

Project description:The activity of many heterogeneous catalysts is limited by strong correlations between activation energies and adsorption energies of reaction intermediates. Although the reaction is thermodynamically favourable at ambient temperature and pressure, the catalytic synthesis of ammonia (NH3), a fertilizer and chemical fuel, from N2 and H2 requires some of the most extreme conditions of the chemical industry. We demonstrate how ammonia can be produced at ambient pressure from air, water, and concentrated sunlight as renewable source of process heat via nitrogen reduction with a looped metal nitride, followed by separate hydrogenation of the lattice nitrogen into ammonia. Separating ammonia synthesis into two reaction steps introduces an additional degree of freedom when designing catalysts with desirable activation and adsorption energies. We discuss the hydrogenation of alkali and alkaline earth metal nitrides and the reduction of transition metal nitrides to outline a promoting role of lattice hydrogen in ammonia evolution. This is rationalized via electronic structure calculations with the activity of nitrogen vacancies controlling the redox-intercalation of hydrogen and the formation and hydrogenation of adsorbed nitrogen species. The predicted trends are confirmed experimentally with evolution of 56.3, 80.7, and 128 ?mol NH3 per mol metal per min at 1 bar and above 550 °C via reduction of Mn6N2.58 to Mn4N and hydrogenation of Ca3N2 and Sr2N to Ca2NH and SrH2, respectively.

| S-EPMC5707470 | biostudies-other

Structurally triggered metal-insulator transition in rare-earth nickelates.

Project description:Rare-earth nickelates form an intriguing series of correlated perovskite oxides. Apart from LaNiO3, they exhibit on cooling a sharp metal-insulator electronic phase transition, a concurrent structural phase transition, and a magnetic phase transition toward an unusual antiferromagnetic spin order. Appealing for various applications, full exploitation of these compounds is still hampered by the lack of global understanding of the interplay between their electronic, structural, and magnetic properties. Here we show from first-principles calculations that the metal-insulator transition of nickelates arises from the softening of an oxygen-breathing distortion, structurally triggered by oxygen-octahedra rotation motions. The origin of such a rare triggered mechanism is traced back in their electronic and magnetic properties, providing a united picture. We further develop a Landau model accounting for the metal-insulator transition evolution in terms of the rare-earth cations and rationalizing how to tune this transition by acting on oxygen rotation motions.

| S-EPMC5700091 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data