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At least 1,279 records · Page 71
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DOE OSTI2020

Materials Data on Ba3TmRu2O9 by Materials Project

Ba3TmRu2O9 is (Cubic) Perovskite-derived structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent RuO6 octahedra, faces with seven BaO12 cuboctahedra, faces with three equivalent TmO6 octahedra, and faces with four equivalent RuO6 octahedra. The corner-sharing octahedral tilt angles are 13°. There are a spread of Ba–O bond distances ranging from 2.92–3.08 Å. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve BaO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, faces with two equivalent TmO6 octahedra, and faces with six equivalent RuO6 octahedra. All Ba–O bond lengths are 2.97 Å. Tm3+ is bonded to six equivalent O2- atoms to form TmO6 octahedra that share corners with six equivalent RuO6 octahedra and faces with eight BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 1°. All Tm–O bond lengths are 2.20 Å. Ru+4.50+ is bonded to six O2- atoms to form RuO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent TmO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one RuO6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are three shorter (1.97 Å) and three longer (2.04 Å) Ru–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to four Ba2+ and two equivalent Ru+4.50+ atoms. In the second O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Tm3+, and one Ru+4.50+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Co3Ru by Materials Project

Co3Ru is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ru is bonded to twelve Co atoms to form RuCo12 cuboctahedra that share corners with six equivalent RuCo12 cuboctahedra, corners with twelve equivalent CoCo8Ru4 cuboctahedra, edges with eighteen CoCo8Ru4 cuboctahedra, faces with eight equivalent RuCo12 cuboctahedra, and faces with twelve CoCo8Ru4 cuboctahedra. There are six shorter (2.53 Å) and six longer (2.56 Å) Ru–Co bond lengths. There are two inequivalent Co sites. In the first Co site, Co is bonded to four equivalent Ru and eight Co atoms to form distorted CoCo8Ru4 cuboctahedra that share corners with four equivalent RuCo12 cuboctahedra, corners with fourteen CoCo8Ru4 cuboctahedra, edges with six equivalent RuCo12 cuboctahedra, edges with twelve CoCo8Ru4 cuboctahedra, faces with four equivalent RuCo12 cuboctahedra, and faces with sixteen CoCo8Ru4 cuboctahedra. There are a spread of Co–Co bond distances ranging from 2.50–2.60 Å. In the second Co site, Co is bonded to four equivalent Ru and eight equivalent Co atoms to form distorted CoCo8Ru4 cuboctahedra that share corners with four equivalent RuCo12 cuboctahedra, corners with fourteen CoCo8Ru4 cuboctahedra, edges with six equivalent RuCo12 cuboctahedra, edges with twelve equivalent CoCo8Ru4 cuboctahedra, faces with four equivalent RuCo12 cuboctahedra, and faces with sixteen CoCo8Ru4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba3FeRu2O9 by Materials Project

Ba3FeRu2O9 is (Cubic) Perovskite-derived structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent RuO6 octahedra, faces with seven BaO12 cuboctahedra, faces with three equivalent FeO6 octahedra, and faces with four equivalent RuO6 octahedra. The corner-sharing octahedral tilt angles are 14°. There are a spread of Ba–O bond distances ranging from 2.88–2.94 Å. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve BaO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, faces with two equivalent FeO6 octahedra, and faces with six equivalent RuO6 octahedra. There are six shorter (2.91 Å) and six longer (2.92 Å) Ba–O bond lengths. Ru+4.50+ is bonded to six O2- atoms to form RuO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent FeO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one RuO6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are three shorter (1.99 Å) and three longer (2.03 Å) Ru–O bond lengths. Fe3+ is bonded to six equivalent O2- atoms to form FeO6 octahedra that share corners with six equivalent RuO6 octahedra and faces with eight BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 1°. All Fe–O bond lengths are 2.06 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Ru+4.50+, and one Fe3+ atom. In the second O2- site, O2- is bonded in a 6-coordinate geometry to four Ba2+ and two equivalent Ru+4.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Al3Ru2 by Materials Project

Al3Ru2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ru is bonded in a 8-coordinate geometry to nine Al atoms. There are a spread of Ru–Al bond distances ranging from 2.53–2.87 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded in a body-centered cubic geometry to eight equivalent Ru atoms. In the second Al site, Al is bonded in a 4-coordinate geometry to five equivalent Ru atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ge2RuC4(Cl3O2)2 by Materials Project

Ru(CO)4(GeCl3)2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four trichlorogermane molecules and two Ru(CO)4 clusters. In each Ru(CO)4 cluster, Ru6+ is bonded in a square co-planar geometry to four equivalent C atoms. There is two shorter (1.97 Å) and two longer (1.98 Å) Ru–C bond length. C is bonded in a linear geometry to one Ru6+ and one O2- atom. The C–O bond length is 1.15 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one C atom. In the second O2- site, O2- is bonded in a single-bond geometry to one C atom. The O–C bond length is 1.15 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba12SrCa3(Ru2O9)4 by Materials Project

Ba12SrCa3(Ru2O9)4 crystallizes in the trigonal P-3 space group. The structure is three-dimensional. there are six inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a distorted q6 geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.86–3.04 Å. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form distorted BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent RuO6 octahedra, faces with seven BaO12 cuboctahedra, faces with three equivalent CaO6 octahedra, and faces with four equivalent RuO6 octahedra. The corner-sharing octahedral tilt angles are 8°. There are a spread of Ba–O bond distances ranging from 2.95–3.31 Å. In the third Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form distorted BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent RuO6 octahedra, faces with six BaO12 cuboctahedra, faces with three equivalent CaO6 octahedra, and faces with four RuO6 octahedra. The corner-sharing octahedral tilt angles are 8°. There are a spread of Ba–O bond distances ranging from 2.92–3.29 Å. In the fourth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent RuO6 octahedra, faces with seven BaO12 cuboctahedra, faces with three equivalent CaO6 octahedra, and faces with four RuO6 octahedra. The corner-sharing octahedral tilt angles are 8°. There are a spread of Ba–O bond distances ranging from 2.95–3.28 Å. In the fifth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, faces with three equivalent BaO12 cuboctahedra, a faceface with one SrO6 octahedra, a faceface with one CaO6 octahedra, and faces with six RuO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.98–3.02 Å. In the sixth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve BaO12 cuboctahedra, faces with six BaO12 cuboctahedra, faces with two CaO6 octahedra, and faces with six RuO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.98–3.02 Å. Sr2+ is bonded to six equivalent O2- atoms to form SrO6 octahedra that share corners with six equivalent RuO6 octahedra and faces with two equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 8°. All Sr–O bond lengths are 2.37 Å. There are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six equivalent O2- atoms to form CaO6 octahedra that share corners with six equivalent RuO6 octahedra and faces with eight BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 6°. All Ca–O bond lengths are 2.28 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six RuO6 octahedra and faces with eight BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 5°. There are three shorter (2.27 Å) and three longer (2.28 Å) Ca–O bond lengths. There are four inequivalent Ru5+ sites. In the first Ru5+ site, Ru5+ is bonded to six O2- atoms to form RuO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent SrO6 octahedra, faces with three equivalent BaO12 cuboctahedra, and a faceface with one RuO6 octahedra. The corner-sharing octahedral tilt angles are 8°. There is three shorter (1.89 Å) and three longer (2.10 Å) Ru–O bond length. In the second Ru5+ site, Ru5+ is bonded to six O2- atoms to form RuO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent CaO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one RuO6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are three shorter (1.91 Å) and three longer (2.09 Å) Ru–O bond lengths. In the third Ru5+ site, Ru5+ is bonded to six O2- atoms to form RuO6 octahedra that share corners with three equivalent CaO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one RuO6 octahedra. The corner-sharing octahedral tilt angles are 5°. There are three shorter (1.91 Å) and three longer (2.09 Å) Ru–O bond lengths. In the fourth Ru5+ site, Ru5+ is bonded to six O2- atoms to form RuO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent CaO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one RuO6 octahedra. The corner-sharing octahedral tilt angles are 5°. There are three shorter (1.91 Å) and three longer (2.09 Å) Ru–O bond lengths. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to three Ba2+, one Sr2+, and one Ru5+ atom. In the second O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Ca2+, and one Ru5+ atom. In the third O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Ca2+, and one Ru5+ atom. In the fourth O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Ca2+, and one Ru5+ atom. In the fifth O2- site, O2- is bonded to four Ba2+ and two Ru5+ atoms to form a mixture of distorted face and corner-sharing OBa4Ru2 octahedra. The corner-sharing octahedra tilt angles range from 6–60°. In the sixth O2- site, O2- is bonded to four Ba2+ and two Ru5+ atoms to form a mixture of distorted face and corner-sharing OBa4Ru2 octahedra. The corner-sharing octahedra tilt angles range from 6–60°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr3Ca3(Ru2O7)2 by Materials Project

Sr3Ca3(Ru2O7)2 is Orthorhombic Perovskite-derived structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are three inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Sr–O bond distances ranging from 2.48–3.08 Å. In the second Sr2+ site, Sr2+ is bonded in a 11-coordinate geometry to eleven O2- atoms. There are a spread of Sr–O bond distances ranging from 2.47–3.18 Å. In the third Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.38–3.06 Å. There are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.30–2.68 Å. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.32–2.73 Å. In the third Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.31–2.74 Å. There are four inequivalent Ru4+ sites. In the first Ru4+ site, Ru4+ is bonded to six O2- atoms to form corner-sharing RuO6 octahedra. The corner-sharing octahedra tilt angles range from 17–27°. There are a spread of Ru–O bond distances ranging from 2.00–2.05 Å. In the second Ru4+ site, Ru4+ is bonded to six O2- atoms to form corner-sharing RuO6 octahedra. The corner-sharing octahedra tilt angles range from 17–28°. There are a spread of Ru–O bond distances ranging from 2.02–2.04 Å. In the third Ru4+ site, Ru4+ is bonded to six O2- atoms to form corner-sharing RuO6 octahedra. The corner-sharing octahedra tilt angles range from 17–28°. There are a spread of Ru–O bond distances ranging from 1.98–2.04 Å. In the fourth Ru4+ site, Ru4+ is bonded to six O2- atoms to form corner-sharing RuO6 octahedra. The corner-sharing octahedra tilt angles range from 17–27°. There are a spread of Ru–O bond distances ranging from 1.99–2.04 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted see-saw-like geometry to one Sr2+, two Ca2+, and one Ru4+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Sr2+, two Ca2+, and one Ru4+ atom. In the third O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Sr2+, two Ca2+, and one Ru4+ atom. In the fourth O2- site, O2- is bonded in a distorted see-saw-like geometry to three Ca2+ and one Ru4+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to four Sr2+ and two Ru4+ atoms. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to four Sr2+ and two Ru4+ atoms. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to two Sr2+, one Ca2+, and two Ru4+ atoms. In the eighth O2- site, O2- is bonded in a 5-coordinate geometry to three Sr2+, one Ca2+, and two Ru4+ atoms. In the ninth O2- site, O2- is bonded in a 5-coordinate geometry to three Sr2+ and two Ru4+ atoms. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to two Sr2+, one Ca2+, and two Ru4+ atoms. In the eleventh O2- site, O2- is bonded in a 5-coordinate geometry to one Sr2+, two Ca2+, and two Ru4+ atoms. In the twelfth O2- site, O2- is bonded in a 5-coordinate geometry to three Sr2+, one Ca2+, and two Ru4+ atoms. In the thirteenth O2- site, O2- is bonded in a 5-coordinate geometry to two Sr2+, one Ca2+, and two Ru4+ atoms. In the fourteenth O2- site, O2- is bonded in a 5-coordinate geometry to one Sr2+, two Ca2+, and two Ru4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ReRu2(NCl)10 by Materials Project

ReCl6(RuN3Cl2)2(N2)2 crystallizes in the monoclinic C2/m space group. The structure is one-dimensional and consists of two hexachlororhenium molecules; four nitrogen molecules; and two RuN3Cl2 ribbons oriented in the (0, 1, 0) direction. In each RuN3Cl2 ribbon, Ru+4.50+ is bonded in a trigonal non-coplanar geometry to three N+0.60- atoms. There is two shorter (1.71 Å) and one longer (1.82 Å) Ru–N bond length. There are two inequivalent N+0.60- sites. In the first N+0.60- site, N+0.60- is bonded in a single-bond geometry to one Ru+4.50+ and one Cl1- atom. The N–Cl bond length is 3.32 Å. In the second N+0.60- site, N+0.60- is bonded in a bent 150 degrees geometry to one Ru+4.50+ and one Cl1- atom. The N–Cl bond length is 1.60 Å. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 1-coordinate geometry to two equivalent N+0.60- and one Cl1- atom. The Cl–Cl bond length is 1.99 Å. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one N+0.60- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Facile Synthesis of Palladium-Based Nanocrystals with Different Crystal Phases and a Comparison of Their Catalytic Properties

A relatively unexplored aspect of noble-metal nanomaterials is polymorphism, or their ability to crystallize in different crystal phases. Here, in this work, a method is reported for the facile synthesis of Ru@Pd core–shell nanocrystals featuring polymorphism, with the core made of hexagonally close-packed (hcp)-Ru while the Pd shell takes either an hcp or face-centered cubic (fcc) phase. The polymorphism shows a dependence on the shell thickness, with shells thinner than ≈1.4 nm taking the hcp phase whereas the thicker ones revert to fcc. The injection rate provides an experimental knob for controlling the phase, with one-shot and drop-wise injection of the Pd precursor corresponding to fcc-Pd and hcp-Pd shells, respectively. When these nanocrystals are tested as catalysts toward formic acid oxidation, the Ru@Pd hcp nanocrystals outperform Ru@Pd fcc in terms of both specific activity and peak potential. Density functional theory calculations are also performed to elucidate the origin of this performance enhancement.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Partial-Single-Atom, Partial-Nanoparticle Composites Enhance Water Dissociation for Hydrogen Evolution

The development of an efficient electrocatalyst toward the hydrogen evolution reaction (HER) is of significant importance in transforming renewable electricity to pure and clean hydrogen by water splitting. However, the construction of an active electrocatalyst with multiple sites that can promote the dissociation of water molecules still remains a great challenge. Herein, a partial-single-atom, partial-nanoparticle composite consisting of nanosized ruthenium (Ru) nanoparticles (NPs) and individual Ru atoms as an energy-efficient HER catalyst in alkaline medium is reported. The formation of this unique composite mainly results from the dispersion of Ru NPs to small-size NPs and single atoms (SAs) on the Fe/N codoped carbon (Fe–N–C) substrate due to the thermodynamic stability. The optimal catalyst exhibits an outstanding HER activity with an ultralow overpotential (9 mV) at 10 mA cm -2 (η 10 ), a high turnover frequency (8.9 H 2 s -1 at 50 mV overpotential), and nearly 100% Faraday efficiency, outperforming the state-of-the-art commercial Pt/C and other reported HER electrocatalysts in alkaline condition. Both experimental and theoretical calculations reveal that the coexistence of Ru NPs and SAs can improve the hydride coupling and water dissociation kinetics, thus synergistically enhancing alkaline hydrogen evolution performance.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Single Atoms Anchored in Hexagonal Boron Nitride for Propane Dehydrogenation from First Principles

We report single-atom catalysts embedded in N-doped graphene have attracted great interest recently, but the hexagonal boron nitride (h-BN) is much less explored as a support. Using first principles density function theory and molecular dynamics, here we investigate the stability of Pt, Au, and Ru single atoms anchored at B and N vacancies on h-BN. We find that Pt and Ru single atoms are much more stable than Au on h-BN. We further examine propane dehydrogenation on these single-atom catalysts and find that Pt 1 at the B vacancy in h-BN and Ru 1 at the N vacancy in h-BN show excellent activity for propane dehydrogenation, as evidenced by low energy barriers for both dehydrogenation steps. Our work suggests that Pt and Ru single atoms anchored at vacancy sites in h-BN could be promising for propane dehydrogenation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Facile Synthesis of Rhodium‐Based Nanocrystals in a Metastable Phase and Evaluation of Their Thermal and Catalytic Properties

Abstract Controlling the polymorphism of metal nanocrystals is a promising strategy for enhancing properties and discovering new phenomena. However, previous studies on Rh nanocrystals have focused on their thermodynamically stable face‐centered‐cubic (fcc) phase. Herein, a facile synthesis of Rh‐based nanocrystals featuring the metastable hexagonal close‐packed (hcp) phase is reported by using Ru seeds in their native hcp phase to template the deposition of Rh atoms. The success of such phase‐controlled synthesis relies on the templating effect promoted by the small lattice mismatch between Ru and Rh and the slow dropwise titration of the precursor at an elevated temperature, ensuring the layer‐by‐layer growth mode and thus the formation of a conformal hcp‐Rh shell. Faster injection rate of Rh(III) precursor leads to the formation of a rough Rh shell in the conventional fcc phase due to accelerated reaction kinetics. Considering both thermodynamic and kinetic aspects of this system, the hcp‐Rh phase is favored when the low surface energy from smooth overlayers balances the high bulk energy of the metastable phase, achieved through tight control of reaction rates and deposition patterns. These Ru hcp @Rh hcp core–shell nanocrystals demonstrate thermal stability up to 400 °C, while exhibiting higher catalytic activity toward ethanol oxidation reaction compared to Ru hcp @Rh fcc counterparts.

Nguyen, Quynh N.↗
DOE OSTI2021

Methods for a blind analysis of isobar data collected by the STAR collaboration

In 2018, the STAR collaboration collected data from $_{44}^{96}{\mathrm{Ru}}+_{44}^{96}{\mathrm{Ru}}$ and $_{40}^{96}{\mathrm{Zr}}+_{40}^{96}{\mathrm{Zr}}$ at $\sqrt{s_\text {NN}}=200$ GeV to search for the presence of the chiral magnetic effect in collisions of nuclei. The isobar collision species alternated frequently between $_{44}^{96}{\mathrm{Ru}}+_{44}^{96}{\mathrm{Ru}}$ and $_{40}^{96}{\mathrm{Zr}}+_{40}^{96}{\mathrm{Zr}}$ . In order to conduct blind analyses of studies related to the chiral magnetic effect in these isobar data, STAR developed a three-step blind analysis procedure. Analysts are initially provided a “reference sample” of data, comprised of a mix of events from the two species, the order of which respects time-dependent changes in run conditions. After tuning analysis codes and performing time-dependent quality assurance on the reference sample, analysts are provided a species-blind sample suitable for calculating efficiencies and corrections for individual $\approx 30$-min data-taking runs. For this sample, species-specific information is disguised, but individual output files contain data from a single isobar species. Only run-by-run corrections and code alteration subsequent to these corrections are allowed at this stage. Following these modifications, the “frozen” code is passed over the fully un-blind data, completing the blind analysis. As a check of the feasibility of the blind analysis procedure, analysts completed a “mock data challenge,” analyzing data from Au + Au collisions at $\sqrt{s_\text {NN}}=27$ GeV, collected in 2018. The Au + Au data were prepared in the same manner intended for the isobar blind data. Finally, the details of the blind analysis procedure and results from the mock data challenge are presented.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2023

Influence of residual chlorine on Ru/TiO 2 active sites during CO 2 methanation

Titania-supported ruthenium (Ru/TiO 2 ) is an established catalyst for the hydrogenation of carbon dioxide to methane (Sabatier reaction). Chlorine contamination, owed to the RuCl 3 precursor, is demonstrated to have a detrimental impact on methanation activity. After calcination and reduction the catalyst contains residual chlorine, shown by XPS. An aqueous ammonia wash removes Cl without leaching Ru. The washed catalysts exhibit improvements in CH 4 site-time yields. Low Ru loading catalysts encounter the greatest activity enhancements after washing (~4.5-fold). DFT calculations indicate that chlorine and CO 2 directly compete for adsorption on Ru step sites, with Cl impeding the adsorption of CO 2 at under-coordinated sites and at higher Cl coverages. H 2 -chemisorption/TPR show that Cl removal lowers the onset of low temperature H 2 dissociation on Ru. Finally, DRIFTS provide evidence that the removal of Cl facilitates low temperature dissociative binding of CO 2 , indicated by the formation of surface bound linear CO species.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

A general strategy and a consolidated mechanism for low-methane hydrogenolysis of polyethylene over ruthenium

Polyethylene (PE) is one of the most environment-threatening plastic waste. Its Ru-catalyzed hydrogenolysis is rapid but produces too much methane. Here, in this study, low-density PE hydrogenolysis is performed at mild conditions and short times over Ru-doped zirconia catalysts (Ru-XZr, X = Ti, Nb, Ce, W, V, Mo, Fe) to determine low-methane catalysts. Methane is produced via direct terminal C-C scission and surface cascade of consecutive C-C scissions, with the latter sensitive to hydrogen availability and dominant in hydrogen-lean conditions. Reactivity studies, characterization and theory reveal that the most effective dopant oxides (W, V, and Mo) are intermediately reducible, as they store and supply extra hydrogen to Ru via reverse hydrogen spillover. This hydrogen readily hydrogenates and desorbs long alkyl surface intermediates that would otherwise produce cascade methane. Our proposed mechanism reconciles the low methane production achieved by increasing the hydrogen pressure or reducing the particle size and exposes the key selectivity descriptors.

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

Discovery of single-atom alloy catalysts for CO 2 -to-methanol reaction by density functional theory calculations

The transformations of CO 2 molecules into valuable products are of increasing interest due to the negative impact of anthropogenic CO 2 emissions on global warming. The CO 2 -to-methanol hydrogenation is an economically profitable reaction of carbon fixation, but it still steps away from widespread industrialization because of the lack of efficient and selective catalysts. Recently, single-atom alloy (SAA) catalysts have been developed to work remarkably in CO 2 hydrogenation reactions. Doping isolated single atoms into metallic catalyst can dramatically alter the catalytic performance of the host. Here, we have performed a screening discovery on Ru and 6 RuX (X = Fe, Co, Ni, Cu, Ir and Pt) SAAs using density functional theory (DFT) computations. We considered 13 possible elementary reactions in 4 possible reaction pathways on Ru and all RuX surfaces. In the computed mechanisms, we found that the formation of *H 2 COOH and *HCOO intermediates plays a critical role in determining catalysts’ activities. Doping Co and Pt isolated single atoms into Ru surface can thermodynamically and kinetically facilitate these intermediates formation processes, eventually promoting the production of methanol. The combination of weak binding and enhanced charge redistribution on RuCo and RuPt surfaces give them improved catalytic activities over pure Ru. This work will ultimately facilitate the discovery and development of SAAs for CO 2 to methanol, serving as guidance to experiments and theoreticians alike.

25 ENERGY STORAGE↗
DOE OSTI2022

Probing neutron-skin thickness with free spectator neutrons in ultracentral high-energy isobaric collisions

We show that the yield ratio of free spectator neutrons produced in high-energy 96 Zr+ 96 Zr to 96 Ru+ 96 Ru collisions is a clean probe of the neutron-skin thickness of colliding nuclei and the slope parameter L of the symmetry energy. The idea is demonstrated based on the proton and neutron density distributions via a state-of-the-art Skyrme-Hartree-Fock-Bogolyubov calculation. Among spectator nucleons given by the Glauber model, free spectator neutrons include those from direct production that survive from clusterization as well as those from deexcitation of heavy clusters described by the popular GEMINI model. More free neutrons are produced in collisions of 96 Zr nucleus due to its larger neutron skin, compared to those produced in collisions of 96 Ru nucleus with a smaller neutron skin. The difference of the free spectator neutron yield is further increased with the increasing difference of the neutron-skin thickness between 96 Zr and 96 Ru with a larger L value, and the increase in ultracentral collisions is particularly insensitive to model details and experimental uncertainties. Since the production of free spectator neutrons is not affected by the complicated dynamics in the mid-rapidity region, the ratio of their multiplicities in ultracentral isobaric collisions is a robust observable for constraining the neutron skin and L value.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

Capture of volatile RuO 4 from oxidized simulated used nuclear fuel solutions

Ruthenium is a challenging fission product in used nuclear fuel (UNF) reprocessing due to its complex redox chemistry, variable speciation in nitric acid, partial extractability, and volatility. This work presents a strategy for Ru removal based on the volatilization of RuO 4 using the strong oxidant sodium bismuthate, followed by RuO 2 deposition onto various substrates. Among the materials tested, polymer-based substrates such as polyolefin wax film (Parafilm®), exhibited superior performance, achieving up to near-quantitative Ru removal from solution. After dissolution of the substrate, 99.6% of the Ru was recovered as RuO 2 . The deposition mechanism onto the polyolefin wax film involves both physisorption and chemical reaction through oxidative cleavage of olefinic bonds within the polymer. In contrast, on inorganic substrates such as Al foil, RuO 4 undergoes incomplete surface adsorption and reduction, as confirmed by FTIR and XPS analyses. This approach remains effective under conditions of simulated oxidation of UNF solutions, selectively removing Ru while leaving other fission products in solution. As a result, capture of RuO 4 offers a practical and efficient strategy for ruthenium decontamination and recovery, offering a route for integration into existing UNF reprocessing flowsheets to enhance overall process safety and performance.

Ruthenium↗