Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “In(HO)3”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Testing electron–phonon coupling for the superconductivity in kagome metal CsV 3 Sb 5

In crystalline materials, electron-phonon coupling (EPC) is a ubiquitous many-body interaction that drives conventional Bardeen-Cooper-Schrieffer superconductivity. Recently, in a new kagome metal CsV 3 Sb 5 , superconductivity that possibly intertwines with time-reversal and spatial symmetry-breaking orders is observed. Density functional theory calculations predicted weak EPC strength, λ, supporting an unconventional pairing mechanism in CsV 3 Sb 5 . However, experimental determination of λ is still missing, hindering a microscopic understanding of the intertwined ground state of CsV 3 Sb 5 . Here, using 7-eV laser-based angle-resolved photoemission spectroscopy and Eliashberg function analysis, we determine an intermediate λ=0.45–0.6 at T = 6 K for both Sb 5p and V 3d electronic bands, which can support a conventional superconducting transition temperature on the same magnitude of experimental value in CsV3Sb5. Remarkably, the EPC on the V 3d-band enhances to λ~0.75 as the superconducting transition temperature elevated to 4.4 K in Cs(V 0.93 Nb 0.07 ) 3 Sb 5 . Our results provide an important clue to understand the pairing mechanism in the kagome superconductor CsV 3 Sb 5 .

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Revisiting spin ice physics in the ferromagnetic Ising pyrochlore Pr 2 Sn 2 O 7

Pyrochlore materials are characterized by their hallmark network of corner-sharing rare-earth tetrahedra, which can produce a wide array of complex magnetic ground states. Ferromagnetic Ising pyrochlores often obey the “two-in-two-out” spin ice rules, which can lead to a highly degenerate spin structure. Large moment systems, such as Ho 2 Ti 2 O 7 and Dy 2 Ti 2 O 7 , tend to host a classical spin ice state with low-temperature spin freezing and emergent magnetic monopoles. Systems with smaller effective moments, such as Pr 3+ -based pyrochlores, have been proposed as excellent candidates for hosting a “quantum spin ice” characterized by entanglement and a slew of exotic quasiparticle excitations. However, experimental evidence for a quantum spin ice state has remained elusive. Here, in this work, we show that the low-temperature magnetic properties of Pr 2 Sn 2 O 7 satisfy several important criteria for continued consideration as a quantum spin ice. We find that Pr 2 Sn 2 O 7 exhibits two distinct spin-correlation time scales of τ ≥ 10 –4 and ~10 –10 s in the spin ice regime. Our comprehensive bulk characterization and neutron scattering measurements enable us to map out the magnetic field-temperature phase diagram, producing results consistent with expectations for a ferromagnetic Ising pyrochlore. We identify key hallmarks of spin ice physics and show that the application of small magnetic fields (μ 0 H c ~0.5 T) suppresses the spin ice state and induces a field-polarized, ordered spin-ice phase. Together, our work clarifies the current state of Pr 2 Sn 2 O 7 and encourages future studies aimed at exploring the potential for a quantum spin ice ground state in this system.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiHo(WO4)2 by Materials Project

LiHo(WO4)2 crystallizes in the monoclinic P2/c space group. The structure is three-dimensional. Li1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are two shorter (2.04 Å) and two longer (2.17 Å) Li–O bond lengths. Ho3+ is bonded to six O2- atoms to form distorted HoO6 octahedra that share corners with eight equivalent WO6 octahedra. The corner-sharing octahedra tilt angles range from 47–61°. There are a spread of Ho–O bond distances ranging from 2.23–2.34 Å. W6+ is bonded to six O2- atoms to form distorted WO6 octahedra that share corners with four equivalent HoO6 octahedra and edges with two equivalent WO6 octahedra. The corner-sharing octahedra tilt angles range from 47–61°. There are a spread of W–O bond distances ranging from 1.82–2.21 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ho3+ and one W6+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Ho3+, and one W6+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+ and two equivalent W6+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ho3+ and two equivalent W6+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Effects of isoalcohol blending with gasoline on autoignition behavior in a rapid compression machine: Isopropanol and isobutanol

Alcohols, and particularly isoalcohols, are potentially advantageous blendstocks towards achieving efficient, low-carbon intensity internal combustion engines. Their use in advanced configurations, such as boosted spark-ignition or spark-assisted compression ignition, requires a comprehensive understanding of their blending effects on the low- and intermediate-temperature autoignition behavior of petroleum-derived gasoline. This work reports an experimental and modeling study of such autoignition characteristics quantified in a twin-piston rapid compression machine. Isopropanol and isobutanol are blended into a research-grade gasoline (FACE-F) at oxygenate blend levels of 0 to 30% vol/vol, with tests conducted at pressures of 20 and 40 bar, temperatures from 700 to 1000 K, and dilute stoichiometric fuel loadings. Changes to overall reactivity, including first-stage and main ignition times, and preliminary exothermicity are established, with comparisons made to previous measurements with ethanol-blended FACE-F gasoline. Furthermore, it is found that at low-temperature/NTC conditions (700–860 K) the isoalcohols suppress first-stage reactivity and associated heat release while main ignition times are extended. At NTC/intermediate-temperature (860–1000 K) conditions changes to fuel reactivity are less significant with isopropanol slightly suppressing reactivity and isobutanol promoting ignition. Detailed chemical kinetic modeling is used to interpret the experimental measurements. Overall trends of suppression or promotion in the blending behavior are reasonably captured by the model. Sensitivity and rate of production analyses indicate that at lower temperatures H-atom abstraction reactions from the surrogate fuel molecules (e.g., cyclopentane, isooctane) and the isoalcohols via OH are important leading to TC 3 H 6 OH and IC 4 H 8 OH–C radicals, for isopropanol and isobutanol respectively, which act as scavengers in the system. At higher temperatures, similar chemistries are dominant, but there is an increasing importance of abstraction by HO 2 . The kinetic modeling also indicates that the promoting effect of isobutanol at higher temperatures is due to the increased abstractions at the γ-sites, while at lower temperatures abstraction at the α-site leads to greater reactivity suppression.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsHo(WO4)2 by Materials Project

CsHo(WO4)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Cs1+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Cs–O bond distances ranging from 2.97–3.49 Å. Ho3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ho–O bond distances ranging from 2.28–2.35 Å. W6+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing WO6 octahedra. The corner-sharing octahedral tilt angles are 41°. There are a spread of W–O bond distances ranging from 1.85–2.18 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Cs1+ and two equivalent W6+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+, one Ho3+, and one W6+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Cs1+, one Ho3+, and two equivalent W6+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Cs1+, one Ho3+, and one W6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Effect of f -element complexation on the radiolysis of 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP])

A systematic study of the impact on the chemical reactivity of the oxidising n-dodecane radical cation (RH˙ + ) with f-element complexed 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) has been undertaken utilizing time-resolved electron pulse radiolysis/transient absorption spectroscopy and high-level quantum mechanical calculations. Lanthanide ion complexed species, [Ln((HEH[EHP]) 2 ) 3 ], exhibited vastly increased reactivity (over 10× faster) in comparison to the non-complexed ligand in n-dodecane solvent, whose rate coefficient was k = (4.66 ± 0.22) × 10 9 M -1 s -1 . Similar reactivity enhancement was also observed for the corresponding americium ion complex, k = (5.58 ± 0.30) × 10 10 M -1 s -1 . The vastly increased reactivity of these f-element complexes was not due to simple increased diffusion-control of these reactions; rather, enhanced hole transfer mechanisms for the complexes were calculated to become energetically more favourable. Interestingly, the observed reactivity trend with lanthanide ion size was not linear; instead, the rate coefficients showed an initial increase (Lu to Yb) followed by a decrease (Tm to Ho), followed by another increase (Dy to La). This behaviour was excellently predicted by the calculated reaction volumes of these complexes. In conclusion, complementary cobalt-60 gamma irradiations for select lanthanide complexes demonstrated that the measured kinetic differences translated to increased ligand degradation at steady-state timescales, affording ~38% increase in ligand loss of a 1:1 [La((HEH[EHP]) 2 ) 3 ]: HEH[EHP] ratio system.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

Materials Data on Ho2CoTe2(SO7)2 by Materials Project

Ho2CoTe2(SO7)2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.26–2.57 Å. Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with two equivalent SO4 tetrahedra. There are a spread of Co–O bond distances ranging from 2.05–2.13 Å. Te4+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Te–O bond distances ranging from 1.90–1.92 Å. S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share a cornercorner with one CoO6 octahedra. The corner-sharing octahedral tilt angles are 45°. There are a spread of S–O bond distances ranging from 1.48–1.51 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to one Ho3+ and one S6+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Co2+ and one S6+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ho3+ and one S6+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ho3+ and one S6+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two equivalent Ho3+ and one Te4+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ho3+, one Co2+, and one Te4+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Ho3+, one Co2+, and one Te4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ho6Pb2Se11 by Materials Project

Ho6Pb2Se11 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. there are six inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded to six Se2- atoms to form HoSe6 octahedra that share corners with three HoSe6 octahedra, corners with two equivalent PbSe7 pentagonal bipyramids, and edges with five HoSe6 octahedra. The corner-sharing octahedra tilt angles range from 9–43°. There are a spread of Ho–Se bond distances ranging from 2.81–2.89 Å. In the second Ho3+ site, Ho3+ is bonded to six Se2- atoms to form HoSe6 octahedra that share corners with three HoSe6 octahedra, corners with two equivalent HoSe7 pentagonal bipyramids, and edges with five HoSe6 octahedra. The corner-sharing octahedra tilt angles range from 7–43°. There are a spread of Ho–Se bond distances ranging from 2.80–2.97 Å. In the third Ho3+ site, Ho3+ is bonded to six Se2- atoms to form HoSe6 octahedra that share corners with three HoSe6 octahedra, corners with four equivalent PbSe7 pentagonal bipyramids, edges with five HoSe6 octahedra, and an edgeedge with one PbSe7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 9–48°. There are a spread of Ho–Se bond distances ranging from 2.81–2.92 Å. In the fourth Ho3+ site, Ho3+ is bonded to six Se2- atoms to form HoSe6 octahedra that share corners with three HoSe6 octahedra, corners with four equivalent HoSe7 pentagonal bipyramids, edges with five HoSe6 octahedra, and an edgeedge with one HoSe7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 7–57°. There are a spread of Ho–Se bond distances ranging from 2.82–2.89 Å. In the fifth Ho3+ site, Ho3+ is bonded to six Se2- atoms to form HoSe6 octahedra that share corners with two HoSe6 octahedra, corners with two equivalent HoSe7 pentagonal bipyramids, corners with two equivalent PbSe7 pentagonal bipyramids, edges with two equivalent HoSe6 octahedra, edges with three equivalent HoSe7 pentagonal bipyramids, and edges with three equivalent PbSe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 48–57°. There are a spread of Ho–Se bond distances ranging from 2.80–2.92 Å. In the sixth Ho3+ site, Ho3+ is bonded to seven Se2- atoms to form distorted HoSe7 pentagonal bipyramids that share corners with eight HoSe6 octahedra, edges with four HoSe6 octahedra, edges with two equivalent PbSe7 pentagonal bipyramids, and faces with two equivalent HoSe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 17–67°. There are a spread of Ho–Se bond distances ranging from 2.86–3.23 Å. There are two inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Pb–Se bond distances ranging from 2.91–3.65 Å. In the second Pb2+ site, Pb2+ is bonded to seven Se2- atoms to form distorted PbSe7 pentagonal bipyramids that share corners with eight HoSe6 octahedra, edges with four HoSe6 octahedra, edges with two equivalent HoSe7 pentagonal bipyramids, and faces with two equivalent PbSe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 24–68°. There are a spread of Pb–Se bond distances ranging from 2.95–3.36 Å. There are eleven inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to three Ho3+ and two equivalent Pb2+ atoms. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ho3+ and two equivalent Pb2+ atoms. In the third Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to two Ho3+ and two equivalent Pb2+ atoms. In the fourth Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to four Ho3+ atoms. In the fifth Se2- site, Se2- is bonded in a 4-coordinate geometry to two Ho3+ and two equivalent Pb2+ atoms. In the sixth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to four Ho3+ and one Pb2+ atom. In the seventh Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to four Ho3+ and one Pb2+ atom. In the eighth Se2- site, Se2- is bonded in a 5-coordinate geometry to three Ho3+ and two equivalent Pb2+ atoms. In the ninth Se2- site, Se2- is bonded in a 5-coordinate geometry to four Ho3+ and one Pb2+ atom. In the tenth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ho3+ and two equivalent Pb2+ atoms. In the eleventh Se2- site, Se2- is bonded to five Ho3+ atoms to form distorted edge-sharing SeHo5 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HoAl3(BO3)4 by Materials Project

HoAl3(BO3)4 is Calcite-derived structured and crystallizes in the trigonal R32 space group. The structure is three-dimensional. Ho3+ is bonded in a 6-coordinate geometry to six equivalent O2- atoms. All Ho–O bond lengths are 2.33 Å. Al3+ is bonded to six O2- atoms to form edge-sharing AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–1.95 Å. There are two inequivalent B3+ sites. In the first B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.38 Å) and one longer (1.39 Å) B–O bond length. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All B–O bond lengths are 1.39 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Al3+ and one B3+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ho3+, one Al3+, and one B3+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Al3+ and one B3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ho2Si2O7 by Materials Project

Ho2Si2O7 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ho3+ is bonded to seven O2- atoms to form distorted HoO7 pentagonal bipyramids that share corners with three equivalent HoO7 pentagonal bipyramids, corners with four SiO4 tetrahedra, edges with two equivalent HoO7 pentagonal bipyramids, and edges with two SiO4 tetrahedra. There are a spread of Ho–O bond distances ranging from 2.22–2.49 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four equivalent HoO7 pentagonal bipyramids, a cornercorner with one SiO4 tetrahedra, and edges with two equivalent HoO7 pentagonal bipyramids. There is three shorter (1.63 Å) and one longer (1.70 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four equivalent HoO7 pentagonal bipyramids, a cornercorner with one SiO4 tetrahedra, and edges with two equivalent HoO7 pentagonal bipyramids. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ho3+ and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ho3+ and one Si4+ atom. In the third O2- site, O2- is bonded in a trigonal planar geometry to two equivalent Ho3+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ho3+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ho3+ and two Si4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HoCuPbS3 by Materials Project

HoCuPbS3 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with two equivalent HoS6 octahedra, edges with two equivalent HoS6 octahedra, and edges with four equivalent CuS4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. There are four shorter (2.73 Å) and two longer (2.78 Å) Ho–S bond lengths. Cu1+ is bonded to four S2- atoms to form CuS4 tetrahedra that share corners with two equivalent CuS4 tetrahedra and edges with four equivalent HoS6 octahedra. There are a spread of Cu–S bond distances ranging from 2.32–2.42 Å. Pb2+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Pb–S bond distances ranging from 2.99–3.32 Å. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a 6-coordinate geometry to two equivalent Ho3+, two equivalent Cu1+, and two equivalent Pb2+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to two equivalent Ho3+, one Cu1+, and three equivalent Pb2+ atoms. In the third S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent Ho3+, one Cu1+, and two equivalent Pb2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Yb Substitution and Ultralow Thermal Conductivity of the Ca 3– x Yb x AlSb 3 (0 ≤ x ≤ 0.81(1)) System

Here, a series of Yb-substituted Zintl phases in the Ca 3–x Yb x AlSb 3 (0 ≤ x ≤ 0.81(1)) system has been synthesized by initial arc melting and post-heat treatment, and their isotypic crystal structures were characterized by both powder and single crystal X-ray diffraction analysis. All four title compounds adopted the Ca 3 AlAs 3 -type structure (space group Pnma, Pearson code oP28, Z = 4). The overall structure can be described as a combination of the 1-dimensional (1D) infinite chain of ∞ 1 [Al(Sb 2 Sb 2/2 )] formed by two vertices sharing [AlSb 4 ] tetrahedral moieties and three Ca 2+ /Yb 2+ mixed sites located in between these 1D chains. The charge balance and the resultant independency of the 1D chains in the title system were explained by the Zintl-Klemm formalism [Ca 2+ /Yb 2+ ] 3 [(4b-Al 1– )(1b-Sb 2– ) 2 (2b-Sb 1– ) 2/2 ]. A series of DFT calculations proved that (1) the band overlap between the d-orbital states from two types of cations and the p-orbital states from Sb at the high symmetry Γ point implied a heavily doped degenerate semiconducting behavior of the quaternary Ca 2 YbAlSb 3 model and (2) the site preference of Yb for the M1 site was due to the electronic-factor criterion based on the Q values of each atomic site. The electron localization function calculations also proved that the two different shapes of lone pairs of the Sb atoms—the “umbrella-shape” and the “C-shape”—are determined by local geometry and the coordination environment on the anionic frameworks. Thermoelectric measurements of the quaternary title compound Ca 2.19(1) Yb 0.81 AlSb 3 showed an approximately two times larger ZT value than that of ternary Ca 3 AlSb 3 at 623 K due to increased electrical conductivity and ultralow thermal conductivity originated from Yb substitution for Ca.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on HoAl3(BO3)4 by Materials Project

HoAl3(BO3)4 is Calcite-derived structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ho3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are four shorter (2.33 Å) and two longer (2.34 Å) Ho–O bond lengths. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form edge-sharing AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–1.95 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form edge-sharing AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–1.95 Å. There are two inequivalent B3+ sites. In the first B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.37–1.39 Å. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.38 Å) and two longer (1.39 Å) B–O bond length. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Ho3+, one Al3+, and one B3+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Al3+ and one B3+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Ho3+, one Al3+, and one B3+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Al3+ and one B3+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Ho3+, one Al3+, and one B3+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Al3+ and one B3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2021

New sterically hindered polyvinylamine-containing membranes for CO 2 capture from flue gas

Amine-containing facilitated transport membranes can have both high permeability and selectivity due to the reversible reaction between CO 2 and amino groups for effective carbon capture from flue gas. In this study, we have developed an improved method for the synthesis of high-molecular-weight sterically hindered polyvinylamine (PVAm) as the new fixed-site carrier in thin-film composite membranes for CO 2 capture. Commercially available PVAm was N-monomethylated into poly-N-methyl-N-vinylamine (PVAm-CH 3 ) using the stepwise reductive amination with a highly polar fluorinated alcohol as the solvent to enhance the equilibrium shift to the formation of the imine intermediate. The method prevented over-alkylation, resulting in the increased yield of the target product. PVAm-CH 3 exhibited excellent CO 2 facilitation with a CO 2 permeability of 445.7 Barrer (1 Barrer = 3.349 x 10 –16 mol m m –2 s –1 Pa –1 ) and a CO 2 /N 2 selectivity of 70.3, which are above the Robeson 2008 upper bound. The PVAm-CH 3 solution retained a sufficiently high viscosity after incorporating the aminoacid salt, 2-(1-piperazinyl)ethylamine sarcosinate (PZEA-Sar), as the mobile carrier for the membrane coating on nanoporous polyethersulfone (PES) substrates without any penetration issues. The resultant thin-film composite PVAm-CH3/PZEA-Sar membrane with a thickness of approximately 170 nm exhibited a superior CO 2 performance of 1071 GPU (1 GPU = 3.349 x 10 –10 mol m –2 s –1 Pa –1 ) and a CO 2 /N 2 selectivity of 183 at 57°C and a feed gas pressure of 111.64 kPa (1.5 psig). This PVAm-CH 3 /PZEA-Sar membrane surpassed the latest redefined 2019 CO 2 /N 2 upper bound and outperformed other polymer-based membranes. Density functional theory calculations also demonstrated that PVAm-CH 3 showed a stronger preference, relative to PVAm, toward the more efficient bicarbonate pathway. Thus, the steric hindrance effect of PVAm-CH 3 enhanced the solubility of CO 2 in the polymer matrix and resulted in the higher CO 2 permeance.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on HoTl(WO4)2 by Materials Project

HoTl(WO4)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ho3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ho–O bond distances ranging from 2.27–2.32 Å. W6+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing WO6 octahedra. The corner-sharing octahedral tilt angles are 44°. There are a spread of W–O bond distances ranging from 1.83–2.14 Å. Tl1+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Tl–O bond distances ranging from 2.88–3.14 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent W6+ and two equivalent Tl1+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Ho3+, one W6+, and one Tl1+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Ho3+, two equivalent W6+, and one Tl1+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ho3+, one W6+, and one Tl1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiHo3Ge2(O4F)2 by Materials Project

LiHo3(GeO4)2F2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Li1+ is bonded in a square co-planar geometry to four O2- atoms. All Li–O bond lengths are 2.12 Å. There are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded to six O2- and one F1- atom to form distorted HoO6F pentagonal bipyramids that share corners with two equivalent HoO6F pentagonal bipyramids, corners with four equivalent GeO4 tetrahedra, an edgeedge with one HoO6F pentagonal bipyramid, and an edgeedge with one GeO4 tetrahedra. There are a spread of Ho–O bond distances ranging from 2.29–2.44 Å. The Ho–F bond length is 2.23 Å. In the second Ho3+ site, Ho3+ is bonded in a 8-coordinate geometry to six O2- and two equivalent F1- atoms. There are a spread of Ho–O bond distances ranging from 2.29–2.56 Å. Both Ho–F bond lengths are 2.24 Å. Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with four equivalent HoO6F pentagonal bipyramids and an edgeedge with one HoO6F pentagonal bipyramid. There are a spread of Ge–O bond distances ranging from 1.76–1.81 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ho3+ and one Ge4+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to one Li1+, two Ho3+, and one Ge4+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to three Ho3+ and one Ge4+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to one Li1+, two Ho3+, and one Ge4+ atom. F1- is bonded in a bent 150 degrees geometry to two Ho3+ atoms.

36 MATERIALS SCIENCE↗