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NASA NTRS1983

The Correlation of Structural, Chemical, and Electronic Properties of Small Metal Particles and Their Alloys

The low pressure interaction of CO with small Ru particles supported on ultrahigh vacuum (UHV) cleaved mica was studied using flash thermal desorption, Auger electron microscopy, transmission electron microscopy, and transmission electron diffraction. Average particle sizes for these experiments varied between 1.2 and 16 nm. A careful search for CO decomposition on the Ru particles revealed no evidence of dissociaiton over a temperature range and pressure range of 300 to 550 C and 10 to the minus 11th power to 10 to the minus 6th millibar, respectively. Cas and heat treatments caused significant morphological changes and dispersion in the Ru particles, which affected CO desorptiom These effects were dependent on the particle size.

Source record↗

NASA NTRS1986

The barium iron ruthenium oxide system

In the system BaFe(1-x)Ru(x)O(3-y), three phases, separated by immiscibility gaps, are present: an Fe-rich phase (x = 0 to 0.75) with hexagonal BaTiO3 structure (6H; sequence (hcc)2), a Ru-rich phase (x = 0.9) of hexagonal 4H-type (sequence (hc)2), and the pure Ru compounds BaRuO3 with rhombohedral 9R structure (sequence (hhc)3). By vibrational spectroscopic investigations in the 6H phase a transition from n-type semiconduction (Fe-rich compounds with complete O lattice) can be detected. The 4H and 9R stacking polytypes are good, metal-like conductors. The lattice parameters are given.

Kemmler-Sack, S.↗

NASA NTRS1987

The applicability of the catalytic wet-oxidation to CELSS

The wet oxidation catalysis of Au, Pd, Pt, Rh or Ru on a ceramic honeycomb carrier was traced in detail by 16 to 20 repetitive batch tests each. As a result, Pt or Pd on a honeycomb carrier was shown to catalyze complete nitrogen gasification as N2. Though the catalysts which realize both complete nitrogen gasification and complete oxidation could not be found, the Ru+Rh catalyst was found to be most promising. Ru honeycomb catalyzed both nitrification and nitrogen gasification.

Takahashi, Y.↗

NASA NTRS1992

Catalysts for ultrahigh current density oxygen cathodes for space fuel cell applications

The objective was to identify promising electrocatalyst/support systems for oxygen cathodes capable of operating at ultrahigh current densities in alkaline fuel cells. Such cells will require operation at relatively high temperatures and O2 pressures. A number of materials were prepared, including Pb-Ru and Pb-Ir pyrochlores, RuO2 and Pt-doped RuO2, lithiated NiO and La-Ni perovskites. Several of these materials were prepared using techniques that had not been previously used to prepare them. Particularly interesting was the use of the alkaline solution technique to prepare Pt-doped and Pb-Ru pyrochlores in high area form. Also interesting was the use of the fusion (melt) method for preparing the Pb-Ru pyrochlore. Several of the materials were also deposited with platinum. Well-crystallized Pb2Ru2O(7-y) was used to fabricate very high performance O2 cathodes with good stability in room temperature KOH. This material was also found to be stable over a useful potential range at approx. 140 C in concentrated KOH. For some of the samples, fabrication of the gas-fed electrodes could not be fully optimized during this project period. Future work may be directed at this problem. Pyrochlores that were not well-crystallized were found to be unstable in alkaline solution. Very good O2 reduction performance and stability were observed with Pb2RuO(7-y) in a carbon-based gas-fed electrode with an anion-conducting membrane placed on the electrolyte side of the electrode. The performance came within a factor of about two of that observed without carbon. High area platinum and gold supported on several conductive metal oxide supports were examined. Only small improvements in O2 reduction performance at room temperature were observed for Pb2Ru2O(7-y) as a support because of the high intrinsic activity of the pyrochlore. In contrast, a large improvement was observed for Li-doped NiO as a support for Pt. Very poor performance was observed for Au deposited on Li-NiO at approx. 150 C. Nearly reversible behavior was observed for the O2/OH(-) couple for Li-doped NiO at approx. 200 C. The temperature dependence for the O2 reduction was examined.

Tryk, Donald A.↗

NASA NTRS1994

Concurrent X-ray and optical observations of two dwarf novae during eruption

The dwarf novae SU UMa and RU Peg were each observed with the ROSAT Observatory during outburst. SU UMa was also observed twice between outbursts. The spectrum of SU UMa during quiescence is well fitted by a 2.1 keV thermal bremsstrahlung model with a Gaussian line at 0.97 keV absorbed by a column density of 1.4 x 10(exp 20)/sq cm. During the outburst the X-ray count rate dropped by a factor of 3. The outburst spectrum is well fitted to a similar spectrum with a significantly larger absorption. In outburst the mass transfer rate, dot-M, approaches the critical value for the optically thin/thick transition predicted by theoretical models of the boundary layer while the X-ray emission remains optically thin. The best-fit model to the outburst spectrum of RU Peg is a 4.9 keV thermal bremsstrahlung plus a line at 0.89 keV absorbed by a column density of 2.8 x 10(exp 20)/sq cm. The column density is consistent with the upper limit determined for interstellar absorption. The boundary layer at outburst is expected to be optically thick based on the value of dot-M determined from the IUE spectra. There are no ROSAT observations of RU Peg between outbursts, but the flux detected by ROSAT is a factor of 10 lower than that seen with the Einstein Observatory, probably during quiescence. For both CVs the X-ray flux from the boundary layer significantly decreases at the same time that the optical-UV flux greatly increases. We suggest that during outburst most of the boundary layer energy is carried away as kinetic energy of the wind.

Silber, A.↗

NASA NTRS2005

Osmium Isotope Evidence for an S-Process Carrier in Primitive Chondrites

The degree of isotopic mixing in the solar nebula and the nature of pre-solar components that have contributed to our solar system remain subjects of vigorous debate. Isotopic anomalies have been identified in Ca-Al inclusions in chondrites [1-4]. This indicates that refractory pre-solar components were not completely homogenized or processed away at the high temperatures experienced by CAIs. Pre-solar grains (SiC, C, etc.) are prevalent in primitive chondrites, and preserve isotopic heterogeneity resulting from the nucleosynthetic processes occurring in the stars from which these grains formed [2,4]. Several recent studies employing precise techniques for measuring Ru, Mo and Zr isotopes in bulk meteorites, have come up with varying conclusions on the degree of effectiveness of nebular mixing on the scale of bulk meteorite material. Some of these studies have reported isotopic anomalies in Mo and Ru [3,5-7], while others have not observed anomalies in Mo, Ru, or Zr [8-10]. Debate over the quality of the data, the normalization techniques employed, the absence or presence of isobaric interferences during the measurements on different types of instruments (e.g. TIMS versus ICP-MS), and other factors, has ensued [11,12].

Brandon, A. D.↗

NASA NTRS2005

The Palladium Isotopic Composition in Iron Meteorites

Ru, Mo and Pd are very useful indicators for the identification of nucleosynthetic components. We have developed techniques for Pd isotopes, in an effort to check the extent of isotopic effects in this mass region and for a Pt-group element which is less refractory than Ru. Stable Pd isotopes are produced by the process only (102Pd), the s-process only (104Pd), the process only (Pd-110) and by both the r- and s-processes (Pd-105, Pd-106, Pd-108). Kelly and Wasserburg reported a hint of a shift in 102Pd (approx. 25(epsilon)u; 1(epsilon)u (triple bonds) 0.01%) in Santa Clara. Earlier searches for Mo and Ru isotopic anomalies were either positive or negative.

Chen, J. H.↗

NASA NTRS2005

Isotopic And Geochemical Investigations Of Meteorites

The primary goals of our research over the past four years are to constrain the timing of certain early planetary accretion/differentiation events, and to constrain the proportions and provenance of materials involved in these processes. This work was achieved via the analysis and interpretation of long- and short-lived isotope systems, and the study of certain trace elements. Our research targeted these goals primarily via the application of the Re-187, Os-187, Pt-190 Os-186 Tc-98 Ru-99 and Tc-99 Ru-99 isotopic systems, and the determination/modeling of abundances of the highly siderophile elements (HSE; including Re, Os, Ir, Ru, Pd, Pt, and maybe Tc). The specific events we examined include the segregation and crystallization histories of asteroidal cores, the accretion and metamorphic histories of chondrites and chondrite components, and the accretionary and differentiation histories of Mars and the Moon.

Walker, Richard J.↗

DOE OSTI2022

Electrocatalyst comprising a crumpled transition metal dichalcogenide support loaded with monodispersed metal nanoparticles

An electrocatalyst comprises a crumpled transition metal dichalcogenide support loaded with catalytic metal nanoparticles through spontaneous reduction reactions. The support can be prepared by hydrothermal conversion of 2D nanosheets to 3D hierarchically crumpled sheets. As an example, using crumpled MoS 2 as a support, highly tunable Ru loadings were obtained using the electrostatic interaction between MoS 2 and RuCl 3 in solution. Control over Ru loading was leveraged to produce Ru—MoS 2 electrocatalysts that demonstrate different nitrogen reduction reaction activities, and which show varying resistance to electrochemical sintering and deactivation. Further, these high surface area materials can be utilized for many applications, including electrocatalysts, supercapacitors, and batteries.

Percival, Stephen↗

DOE OSTI2023

On the Operando Structure of Ruthenium Oxides during the Oxygen Evolution Reaction in Acidic Media

In the search for rational design strategies for oxygen evolution reaction (OER) catalysts, linking the catalyst structure to activity and stability is key. However, highly active catalysts such as IrO x and RuO x undergo structural changes under OER conditions, and hence, structure–activity–stability relationships need to take into account the operando structure of the catalyst. Under the highly anodic conditions of the oxygen evolution reaction (OER), electrocatalysts are often converted into an active form. Here, we studied this activation for amorphous and crystalline ruthenium oxide using X-ray absorption spectroscopy (XAS) and electrochemical scanning electron microscopy (EC-SEM). We tracked the evolution of surface oxygen species in ruthenium oxides while in parallel mapping the oxidation state of the Ru atoms to draw a complete picture of the oxidation events that lead to the OER active structure. Our data show that a large fraction of the OH groups in the oxide are deprotonated under OER conditions, leading to a highly oxidized active material. The oxidation is centered not only on the Ru atoms but also on the oxygen lattice. This oxygen lattice activation is particularly strong for amorphous RuO x . We propose that this property is key for the high activity and low stability observed for amorphous ruthenium oxide.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Microwave-assisted ammonia synthesis over Ru/MgO catalysts at ambient pressure

Here, in this work, a fixed frequency (2.45 GHz) microwave (MW) was used to synthesis ammonia over Ru/MgO catalysts under ambient atmospheric pressure at 320 °C. The loading of Ru catalyst over MgO was varied at 4% and 10 wt %. The metal support interaction was found to play an important role not only catalytically but also altering the microwave-catalyst interaction affecting the ammonia formation rate. The higher metal loading (10 wt%) produced the most activity, stability, and energy efficiency. It was found the Ru was better dispersed at higher loading which decreased the sintering of the catalyst due to lower microwave energy needed to maintain the reaction temperature. Additional effects from the microwave can include enhanced electron movement and/or electric fields formed between the metal sites of the catalyst. The microwave reactor offers a quick on/off catalyst recovery, within 11 min, compared to thermal convectional Haber Bosch (HB) technology.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Materials Data on SiRu2 by Materials Project

Ru2Si is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Ru2+ sites. In the first Ru2+ site, Ru2+ is bonded in a 5-coordinate geometry to five equivalent Si4- atoms. There are a spread of Ru–Si bond distances ranging from 2.47–2.88 Å. In the second Ru2+ site, Ru2+ is bonded in a 5-coordinate geometry to five equivalent Si4- atoms. There are a spread of Ru–Si bond distances ranging from 2.45–2.86 Å. Si4- is bonded in a 10-coordinate geometry to ten Ru2+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on TiSiRu by Materials Project

TiRuSi crystallizes in the orthorhombic Ima2 space group. The structure is three-dimensional. there are three inequivalent Ti2+ sites. In the first Ti2+ site, Ti2+ is bonded to five Si4- atoms to form TiSi5 trigonal bipyramids that share corners with five equivalent TiSi5 square pyramids, corners with six RuSi4 tetrahedra, edges with two equivalent TiSi5 square pyramids, edges with six RuSi4 tetrahedra, and edges with two equivalent TiSi5 trigonal bipyramids. There are a spread of Ti–Si bond distances ranging from 2.63–2.68 Å. In the second Ti2+ site, Ti2+ is bonded to five Si4- atoms to form distorted TiSi5 square pyramids that share corners with six RuSi4 tetrahedra, corners with five equivalent TiSi5 trigonal bipyramids, edges with two equivalent TiSi5 square pyramids, edges with six RuSi4 tetrahedra, and edges with two equivalent TiSi5 trigonal bipyramids. There are two shorter (2.63 Å) and three longer (2.64 Å) Ti–Si bond lengths. In the third Ti2+ site, Ti2+ is bonded in a 5-coordinate geometry to five Si4- atoms. There are a spread of Ti–Si bond distances ranging from 2.63–2.88 Å. There are two inequivalent Ru2+ sites. In the first Ru2+ site, Ru2+ is bonded to four Si4- atoms to form RuSi4 tetrahedra that share corners with two equivalent TiSi5 square pyramids, corners with ten RuSi4 tetrahedra, corners with two equivalent TiSi5 trigonal bipyramids, edges with two equivalent TiSi5 square pyramids, edges with two equivalent RuSi4 tetrahedra, and edges with two equivalent TiSi5 trigonal bipyramids. There are two shorter (2.48 Å) and two longer (2.49 Å) Ru–Si bond lengths. In the second Ru2+ site, Ru2+ is bonded to four Si4- atoms to form RuSi4 tetrahedra that share corners with two equivalent TiSi5 square pyramids, corners with ten RuSi4 tetrahedra, corners with two equivalent TiSi5 trigonal bipyramids, edges with two equivalent TiSi5 square pyramids, edges with two RuSi4 tetrahedra, and edges with two equivalent TiSi5 trigonal bipyramids. There are a spread of Ru–Si bond distances ranging from 2.41–2.46 Å. There are two inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 10-coordinate geometry to three Ti2+ and six Ru2+ atoms. In the second Si4- site, Si4- is bonded in a 9-coordinate geometry to six Ti2+ and three Ru2+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on PRu by Materials Project

Ru(P) is Modderite structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ru3+ is bonded to six equivalent P3- atoms to form a mixture of distorted corner, edge, and face-sharing RuP6 octahedra. The corner-sharing octahedra tilt angles range from 43–59°. There are a spread of Ru–P bond distances ranging from 2.35–2.54 Å. P3- is bonded in a 8-coordinate geometry to six equivalent Ru3+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Tb2Si5Ru3 by Materials Project

Tb2Ru3Si5 crystallizes in the orthorhombic Ibam space group. The structure is three-dimensional. Tb3+ is bonded in a 10-coordinate geometry to ten Si+2.40- atoms. There are a spread of Tb–Si bond distances ranging from 2.96–3.33 Å. There are two inequivalent Ru2+ sites. In the first Ru2+ site, Ru2+ is bonded to five Si+2.40- atoms to form a mixture of distorted corner and edge-sharing RuSi5 trigonal bipyramids. There are a spread of Ru–Si bond distances ranging from 2.38–2.44 Å. In the second Ru2+ site, Ru2+ is bonded in a distorted hexagonal planar geometry to six Si+2.40- atoms. There are four shorter (2.45 Å) and two longer (2.53 Å) Ru–Si bond lengths. There are three inequivalent Si+2.40- sites. In the first Si+2.40- site, Si+2.40- is bonded in a 4-coordinate geometry to four equivalent Tb3+ and four equivalent Ru2+ atoms. In the second Si+2.40- site, Si+2.40- is bonded in a 11-coordinate geometry to four equivalent Tb3+, three Ru2+, and four Si+2.40- atoms. There are two shorter (2.55 Å) and two longer (2.81 Å) Si–Si bond lengths. In the third Si+2.40- site, Si+2.40- is bonded in a 6-coordinate geometry to four equivalent Tb3+, three Ru2+, and two equivalent Si+2.40- atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Ba4Ru3O10 by Materials Project

Ba4Ru3O10 crystallizes in the orthorhombic Cmce space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Ba–O bond distances ranging from 2.63–2.99 Å. In the second Ba2+ site, Ba2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Ba–O bond distances ranging from 2.75–3.15 Å. There are two inequivalent Ru4+ sites. In the first Ru4+ site, Ru4+ is bonded to six O2- atoms to form a mixture of face and corner-sharing RuO6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are a spread of Ru–O bond distances ranging from 1.95–2.13 Å. In the second Ru4+ site, Ru4+ is bonded to six O2- atoms to form face-sharing RuO6 octahedra. All Ru–O bond lengths are 2.05 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to four Ba2+ and two Ru4+ atoms. In the second O2- site, O2- is bonded to four Ba2+ and two Ru4+ atoms to form a mixture of distorted edge and corner-sharing OBa4Ru2 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. In the third O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two equivalent Ru4+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+ and one Ru4+ atom.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on P4Ru by Materials Project

RuP4 is Hausmannite-like structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Ru4+ sites. In the first Ru4+ site, Ru4+ is bonded to six P1- atoms to form RuP6 octahedra that share corners with two equivalent RuP6 octahedra, corners with fourteen PP3Ru tetrahedra, and an edgeedge with one RuP6 octahedra. The corner-sharing octahedra tilt angles range from 53–56°. There are a spread of Ru–P bond distances ranging from 2.33–2.42 Å. In the second Ru4+ site, Ru4+ is bonded to six P1- atoms to form RuP6 octahedra that share corners with four equivalent RuP6 octahedra and corners with fourteen PP3Ru tetrahedra. The corner-sharing octahedra tilt angles range from 53–56°. There are a spread of Ru–P bond distances ranging from 2.37–2.40 Å. There are six inequivalent P1- sites. In the first P1- site, P1- is bonded to one Ru4+ and three P1- atoms to form PP3Ru tetrahedra that share corners with five RuP6 octahedra and corners with nine PP3Ru tetrahedra. The corner-sharing octahedra tilt angles range from 60–80°. There are a spread of P–P bond distances ranging from 2.17–2.31 Å. In the second P1- site, P1- is bonded to two Ru4+ and two P1- atoms to form PP2Ru2 tetrahedra that share corners with two RuP6 octahedra and corners with fourteen PP3Ru tetrahedra. The corner-sharing octahedra tilt angles range from 65–72°. The P–P bond length is 2.19 Å. In the third P1- site, P1- is bonded to one Ru4+ and three P1- atoms to form PP3Ru tetrahedra that share corners with five RuP6 octahedra and corners with nine PP3Ru tetrahedra. The corner-sharing octahedra tilt angles range from 51–79°. There are one shorter (2.22 Å) and one longer (2.31 Å) P–P bond lengths. In the fourth P1- site, P1- is bonded to two Ru4+ and two P1- atoms to form PP2Ru2 tetrahedra that share corners with two equivalent RuP6 octahedra and corners with fourteen PP3Ru tetrahedra. The corner-sharing octahedra tilt angles range from 54–65°. The P–P bond length is 2.23 Å. In the fifth P1- site, P1- is bonded to two equivalent Ru4+ and two P1- atoms to form PP2Ru2 tetrahedra that share corners with three RuP6 octahedra, corners with eleven PP3Ru tetrahedra, and an edgeedge with one PP2Ru2 tetrahedra. The corner-sharing octahedra tilt angles range from 60–71°. The P–P bond length is 2.21 Å. In the sixth P1- site, P1- is bonded to one Ru4+ and three P1- atoms to form PP3Ru tetrahedra that share corners with four RuP6 octahedra and corners with ten PP3Ru tetrahedra. The corner-sharing octahedra tilt angles range from 44–78°. The P–P bond length is 2.22 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on P3Ru by Materials Project

RuP3 is Hausmannite-like structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Ru2+ sites. In the first Ru2+ site, Ru2+ is bonded to six P+0.67- atoms to form RuP6 octahedra that share corners with five equivalent RuP6 octahedra, corners with nine PP3Ru tetrahedra, and edges with two equivalent RuP6 octahedra. The corner-sharing octahedra tilt angles range from 41–63°. There are a spread of Ru–P bond distances ranging from 2.36–2.42 Å. In the second Ru2+ site, Ru2+ is bonded to six P+0.67- atoms to form RuP6 octahedra that share corners with five equivalent RuP6 octahedra, corners with eleven PPRu3 tetrahedra, and an edgeedge with one RuP6 octahedra. The corner-sharing octahedra tilt angles range from 41–63°. There are a spread of Ru–P bond distances ranging from 2.31–2.42 Å. There are six inequivalent P+0.67- sites. In the first P+0.67- site, P+0.67- is bonded to three Ru2+ and one P+0.67- atom to form distorted PPRu3 tetrahedra that share a cornercorner with one RuP6 octahedra, corners with fifteen PP3Ru tetrahedra, and an edgeedge with one PPRu3 tetrahedra. The corner-sharing octahedral tilt angles are 70°. The P–P bond length is 2.22 Å. In the second P+0.67- site, P+0.67- is bonded to one Ru2+ and three P+0.67- atoms to form distorted PP3Ru tetrahedra that share corners with five RuP6 octahedra and corners with nine PPRu3 tetrahedra. The corner-sharing octahedra tilt angles range from 58–72°. There are a spread of P–P bond distances ranging from 2.21–2.24 Å. In the third P+0.67- site, P+0.67- is bonded to one Ru2+ and three P+0.67- atoms to form PP3Ru tetrahedra that share corners with six RuP6 octahedra and corners with eight PPRu3 tetrahedra. The corner-sharing octahedra tilt angles range from 54–82°. The P–P bond length is 2.22 Å. In the fourth P+0.67- site, P+0.67- is bonded to three Ru2+ and one P+0.67- atom to form PPRu3 tetrahedra that share a cornercorner with one RuP6 octahedra, corners with fifteen PPRu3 tetrahedra, and an edgeedge with one PPRu3 tetrahedra. The corner-sharing octahedral tilt angles are 60°. In the fifth P+0.67- site, P+0.67- is bonded to two Ru2+ and two P+0.67- atoms to form PP2Ru2 tetrahedra that share corners with four RuP6 octahedra and corners with twelve PPRu3 tetrahedra. The corner-sharing octahedra tilt angles range from 66–77°. There are one shorter (2.20 Å) and one longer (2.22 Å) P–P bond lengths. In the sixth P+0.67- site, P+0.67- is bonded to two equivalent Ru2+ and two P+0.67- atoms to form PP2Ru2 tetrahedra that share corners with three RuP6 octahedra, corners with eleven PPRu3 tetrahedra, and an edgeedge with one PP2Ru2 tetrahedra. The corner-sharing octahedra tilt angles range from 68–73°.

36 MATERIALS SCIENCE↗