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All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Ir–Ru Particles Enable Low-Loading Acidic Oxygen Evolution for Integrated Solar Devices

Integrated photoelectrochemical (PEC) devices for water splitting represent a compelling pathway for sustainable hydrogen production, directly converting solar energy into chemical fuels. While alkaline systems have achieved state-of-the-art solar-to-hydrogen (STH) efficiencies above 20% using earth-abundant catalysts, acidic PEC architectures provide unique advantages for compact device integration, fast proton transport, and stable operation under highly dynamic solar conditions. Proton-exchange membrane (PEM)-based configurations enable high current densities, low gas crossover, and rapid ionic response, making them especially well-suited for intermittent, bias-free PEC operation, despite alkaline electrolysis being more technologically mature. A critical limitation of acidic PEC systems remains, the oxygen evolution reaction (OER), which currently relies on scarce and costly iridium catalysts, restricting scalability. Here, in this study, we report a series of low-iridium mixed-metal oxide catalysts synthesized via a surfactant-assisted borohydride reduction method. An optimized Ir 0.5 Ru 0.5 O x catalyst exhibits exceptional intrinsic activity (>400 A g –1 Ir at 1.55 V vs RHE) in 0.1 M HClO 4 and maintains stable operation for over 10 days in an integrated PEC flow-cell. Sustained hydrogen production is achieved at 1.65 V with a total iridium loading of only 0.1 mg cm –2 , substantially below commercial PEM benchmarks. These results demonstrate a viable pathway toward scalable, high-performance acidic PEC hydrogen technologies.

Acidic electrolysis↗
DOE OSTI2021

Ferrotorryweiserite, Rh 5 Fe 10 S 16 , a New Mineral Species from the Sisim Placer Zone, Eastern Sayans, Russia, and the Torryweiserite–Ferrotorryweiserite Series

Ferrotorryweiserite, Rh 5 Fe 10 S 16 , occurs as small grains (≤20 µm) among droplet-like inclusions (up to 50 μm in diameter) of platinum-group minerals (PGM), in association with oberthürite or Rh-bearing pentlandite, laurite, and a Pt-Pd-Fe alloy (likely isoferroplatinum and Fe-Pd-enriched platinum), hosted by placer grains of Os-Ir alloy (≤0.5 mm) in the River Ko deposit. The latter is a part of the Sisim placer zone, which is likely derived from ultramafic units of the Lysanskiy layered complex, southern Krasnoyarskiy kray, Russia. The mineral is opaque, gray to brownish gray in reflected light, very weakly bireflectant, not pleochroic to weakly pleochroic (grayish to light brown tints), and weakly anisotropic. The calculated density is 5.93 g·cm –3 . Mean results (and ranges) of four WDS analyses are: Ir 18.68 (15.55–21.96), Rh 18.34 (16.32–20.32), Pt 0.64 (0.19–1.14), Ru 0.03 (0.00–0.13), Os 0.07 (0.02–0.17), Fe 14.14 (13.63–14.64), Ni 13.63 (12.58–14.66), Cu 4.97 (3.42–6.41), Co 0.09 (0.07–0.11), S 29.06 (28.48–29.44), and total 99.66 wt.%. They correspond to the following formula calculated for a total of 31 atoms per formula unit: (Rh 3.16 Ir 1.72 Pt 0.06 Ru 0.01 Os 0.01 ) Σ 4.95 (Fe 4.48 Ni 4.11 Cu 1.38 Co 0.03 ) Σ10.00 S 16.05 . The results of synchrotron micro-Laue diffraction studies indicate that ferrotorryweiserite is trigonal; its probable space group is $R\bar{3}m$ (#166) based on its Ni-analog, torryweiserite. The unit-cell parameters refined from 177 reflections are a = 7.069 (2) Å, c = 34.286 (11) Å, V = 1484 (1) Å 3 , and Z = 3. The c:a ratio is 4.8502. The strongest eight peaks in the X-ray diffraction pattern derived from results of micro-Laue diffraction study [d in Å(hkil)(I)] are 2.7950 ($20\bar{2}5$) (100); 5.7143 (0006) (60); 1.7671 ($22\bar{4}0$) (44.4); 3.0486 ($20\bar{2}1$) (39.4); 5.7650 ($10\bar{1}2$) (38.6); 2.5956 ($20\bar{2}7$) (37.8); 3.0058 ($11\bar{2}6$) (36.5); and 1.5029 ($4\bar{2}\bar{2}12$) (35.3). Ferrotorryweiserite and the associated PGM crystallized from microvolumes of residual melt at late stages of crystallization of grains of Os- and Ir-dominant alloys occurred in lode zones of chromitites of the Lysanskiy layered complex. In a particular case, the residual melt is disposed peripherally around a core containing a disequilibrium association of magnesian olivine (Fo 72.9–75.6 ) and albite (Ab 81.6–86.4 ), with the development of skeletal crystals of titaniferous augite: Wo 40.8–43.2 En 26.5–29.3 Fs 20.3–22.6 Aeg 6.9–9.5 (2.82–3.12 wt.% TiO 2 ). Ferrotorryweiserite represents the Fe-dominant analog of torryweiserite. We also report occurrences of ferrotorryweiserite in the Marathon deposit, Coldwell Complex, Ontario, Canada, and infer the existence of the torryweiserite–ferrotorryweiserite solid solution in other deposits and complexes.

58 GEOSCIENCES↗
DOE OSTI2020

Materials Data on B8Ru11 by Materials Project

Ru11B8 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. there are six inequivalent Ru+2.18+ sites. In the first Ru+2.18+ site, Ru+2.18+ is bonded in a 5-coordinate geometry to five B3- atoms. There are a spread of Ru–B bond distances ranging from 2.23–2.76 Å. In the second Ru+2.18+ site, Ru+2.18+ is bonded in a square co-planar geometry to four equivalent B3- atoms. All Ru–B bond lengths are 2.25 Å. In the third Ru+2.18+ site, Ru+2.18+ is bonded in a 6-coordinate geometry to six B3- atoms. There are two shorter (2.29 Å) and four longer (2.32 Å) Ru–B bond lengths. In the fourth Ru+2.18+ site, Ru+2.18+ is bonded in a trigonal non-coplanar geometry to three B3- atoms. There are two shorter (2.12 Å) and one longer (2.19 Å) Ru–B bond lengths. In the fifth Ru+2.18+ site, Ru+2.18+ is bonded in a 7-coordinate geometry to seven B3- atoms. There are a spread of Ru–B bond distances ranging from 2.21–2.46 Å. In the sixth Ru+2.18+ site, Ru+2.18+ is bonded in a 4-coordinate geometry to four B3- atoms. There are a spread of Ru–B bond distances ranging from 2.15–2.53 Å. There are four inequivalent B3- sites. In the first B3- site, B3- is bonded in a 7-coordinate geometry to seven Ru+2.18+ atoms. In the second B3- site, B3- is bonded in a 7-coordinate geometry to six Ru+2.18+ and two equivalent B3- atoms. Both B–B bond lengths are 1.80 Å. In the third B3- site, B3- is bonded in a 2-coordinate geometry to eight Ru+2.18+ and one B3- atom. The B–B bond length is 2.01 Å. In the fourth B3- site, B3- is bonded in a 9-coordinate geometry to six Ru+2.18+ and three B3- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr8Fe2Ru2O13 by Materials Project

Sr8Ru2Fe2O13 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to seven O2- atoms to form distorted SrO7 pentagonal bipyramids that share corners with three equivalent SrO7 pentagonal bipyramids, a cornercorner with one FeO5 square pyramid, edges with three equivalent SrO7 pentagonal bipyramids, an edgeedge with one FeO5 square pyramid, and a faceface with one SrO7 pentagonal bipyramid. There are a spread of Sr–O bond distances ranging from 2.48–2.76 Å. In the second Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.53–2.84 Å. Ru2+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Ru–O bond distances ranging from 1.90–2.07 Å. Fe3+ is bonded to five O2- atoms to form FeO5 square pyramids that share corners with two equivalent SrO7 pentagonal bipyramids, corners with two equivalent FeO5 square pyramids, and edges with two equivalent SrO7 pentagonal bipyramids. There are a spread of Fe–O bond distances ranging from 1.89–2.04 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Sr2+ and two equivalent Ru2+ atoms to form distorted OSr4Ru2 octahedra that share corners with fourteen OSr5Fe octahedra, edges with two equivalent OSr4FeRu octahedra, and faces with four equivalent OSr5Ru octahedra. The corner-sharing octahedra tilt angles range from 4–63°. In the second O2- site, O2- is bonded to four Sr2+, one Ru2+, and one Fe3+ atom to form distorted OSr4FeRu octahedra that share corners with fourteen OSr4Ru2 octahedra, edges with two OSr4Ru2 octahedra, and faces with five OSr5Fe octahedra. The corner-sharing octahedra tilt angles range from 4–61°. In the third O2- site, O2- is bonded to four equivalent Sr2+ and two equivalent Fe3+ atoms to form distorted OSr4Fe2 octahedra that share corners with fourteen OSr5Fe octahedra, edges with two equivalent OSr4FeRu octahedra, and faces with six OSr5Fe octahedra. The corner-sharing octahedra tilt angles range from 4–58°. In the fourth O2- site, O2- is bonded to four equivalent Sr2+ and two equivalent Fe3+ atoms to form a mixture of distorted corner and face-sharing OSr4Fe2 octahedra. The corner-sharing octahedra tilt angles range from 46–55°. In the fifth O2- site, O2- is bonded to five Sr2+ and one Fe3+ atom to form distorted OSr5Fe octahedra that share corners with twelve OSr4Ru2 octahedra, edges with eight OSr5Fe octahedra, and faces with three OSr4FeRu octahedra. The corner-sharing octahedra tilt angles range from 6–63°. In the sixth O2- site, O2- is bonded to five Sr2+ and one Ru2+ atom to form OSr5Ru octahedra that share corners with thirteen OSr4Ru2 octahedra, edges with eight OSr5Fe octahedra, and faces with two OSr4Ru2 octahedra. The corner-sharing octahedra tilt angles range from 3–61°.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Optimizing feed modulation for coupled methane and NO x conversion over Pd-Pt/Mn 0.5 Fe 2.5 O 4 /Al 2 O 3 monolith catalyst

Here the impacts of feed modulation (frequency, amplitude) and catalyst design (composition and architecture) parameters are reported for the conversion of methane and NO x over a dual-layer Pt+Pd/Al 2 O 3 + Mn 0.5 Fe 2.5 O 4 /Al 2 O 3 monolith. CH 4 and NO x conversion data show that the dual-layer catalyst outperforms single-layer samples having the same catalyst loadings, with and without spinel. Close proximity of the PGM and MFO functions in the mixed-layer catalyst lowers the CH 4 conversion at high temperature while separating the PGM and spinel layers with an intermediate Al 2 O 3 layer does not. Methane conversion enhancement is linked to its nonmonotonic dependence on O 2 . The performance gains are tied to a transient activity spike that occurs during the lean-to-rich feed transition when water is present in the feed. The transient spike is attributed to the removal of CO and H 2 products via reactions with stored O 2 in the spinel, eliminating inhibition of methane steam reforming.

03 NATURAL GAS↗
DOE OSTI2020

Materials Data on Er17(TeRu2)3 by Materials Project

Er17Ru6Te3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are eighteen inequivalent Er sites. In the first Er site, Er is bonded in a 4-coordinate geometry to three equivalent Ru and one Te atom. There are two shorter (2.80 Å) and one longer (3.30 Å) Er–Ru bond lengths. The Er–Te bond length is 3.13 Å. In the second Er site, Er is bonded in a 5-coordinate geometry to three Ru and two equivalent Te atoms. There are two shorter (2.93 Å) and one longer (3.21 Å) Er–Ru bond lengths. Both Er–Te bond lengths are 3.48 Å. In the third Er site, Er is bonded in a 2-coordinate geometry to three equivalent Ru and two equivalent Te atoms. There are two shorter (2.90 Å) and one longer (3.53 Å) Er–Ru bond lengths. Both Er–Te bond lengths are 3.44 Å. In the fourth Er site, Er is bonded to three Ru and one Te atom to form a mixture of distorted edge and corner-sharing ErTeRu3 tetrahedra. There are two shorter (2.83 Å) and one longer (2.99 Å) Er–Ru bond lengths. The Er–Te bond length is 3.12 Å. In the fifth Er site, Er is bonded in a 2-coordinate geometry to three Ru and two equivalent Te atoms. There are two shorter (2.83 Å) and one longer (3.43 Å) Er–Ru bond lengths. Both Er–Te bond lengths are 3.40 Å. In the sixth Er site, Er is bonded in a 4-coordinate geometry to three Ru and one Te atom. There are two shorter (2.85 Å) and one longer (3.15 Å) Er–Ru bond lengths. The Er–Te bond length is 3.12 Å. In the seventh Er site, Er is bonded in a 6-coordinate geometry to four Ru and two equivalent Te atoms. There are two shorter (2.87 Å) and two longer (3.07 Å) Er–Ru bond lengths. Both Er–Te bond lengths are 3.30 Å. In the eighth Er site, Er is bonded in a 2-coordinate geometry to three Ru and two equivalent Te atoms. There are two shorter (2.81 Å) and one longer (3.43 Å) Er–Ru bond lengths. Both Er–Te bond lengths are 3.34 Å. In the ninth Er site, Er is bonded in a 2-coordinate geometry to three Ru and two equivalent Te atoms. There are two shorter (2.79 Å) and one longer (3.55 Å) Er–Ru bond lengths. Both Er–Te bond lengths are 3.35 Å. In the tenth Er site, Er is bonded to three Ru and one Te atom to form distorted corner-sharing ErTeRu3 tetrahedra. There are two shorter (2.86 Å) and one longer (2.92 Å) Er–Ru bond lengths. The Er–Te bond length is 3.12 Å. In the eleventh Er site, Er is bonded to three Ru and one Te atom to form a mixture of distorted edge and corner-sharing ErTeRu3 tetrahedra. There are two shorter (2.84 Å) and one longer (2.87 Å) Er–Ru bond lengths. The Er–Te bond length is 3.14 Å. In the twelfth Er site, Er is bonded in a 5-coordinate geometry to three Ru and two equivalent Te atoms. There are two shorter (2.91 Å) and one longer (3.25 Å) Er–Ru bond lengths. Both Er–Te bond lengths are 3.37 Å. In the thirteenth Er site, Er is bonded in a 6-coordinate geometry to four Ru and two equivalent Te atoms. There are two shorter (2.87 Å) and two longer (3.08 Å) Er–Ru bond lengths. Both Er–Te bond lengths are 3.31 Å. In the fourteenth Er site, Er is bonded in a 4-coordinate geometry to three Ru and one Te atom. There are two shorter (2.81 Å) and one longer (3.19 Å) Er–Ru bond lengths. The Er–Te bond length is 3.09 Å. In the fifteenth Er site, Er is bonded in a 5-coordinate geometry to three Ru and two equivalent Te atoms. There are two shorter (2.91 Å) and one longer (3.25 Å) Er–Ru bond lengths. Both Er–Te bond lengths are 3.37 Å. In the sixteenth Er site, Er is bonded to three Ru and one Te atom to form a mixture of distorted edge and corner-sharing ErTeRu3 tetrahedra. There are two shorter (2.79 Å) and one longer (3.02 Å) Er–Ru bond lengths. The Er–Te bond length is 3.10 Å. In the seventeenth Er site, Er is bonded in a square co-planar geometry to two equivalent Ru and two equivalent Te atoms. Both Er–Ru bond lengths are 3.11 Å. Both Er–Te bond lengths are 3.23 Å. In the eighteenth Er site, Er is bonded in a square co-planar geometry to two equivalent Ru and two equivalent Te atoms. Both Er–Ru bond lengths are 3.18 Å. Both Er–Te bond lengths are 3.15 Å. There are six inequivalent Ru sites. In the first Ru site, Ru is bonded in a 9-coordinate geometry to eight Er atoms. In the second Ru site, Ru is bonded in a 9-coordinate geometry to nine Er atoms. In the third Ru site, Ru is bonded in a 9-coordinate geometry to eight Er atoms. In the fourth Ru site, Ru is bonded in a 9-coordinate geometry to nine Er atoms. In the fifth Ru site, Ru is bonded in a 9-coordinate geometry to nine Er atoms. In the sixth Ru site, Ru is bonded in a 9-coordinate geometry to nine Er atoms. There are three inequivalent Te sites. In the first Te site, Te is bonded in a 9-coordinate geometry to nine Er atoms. In the second Te site, Te is bonded in a 9-coordinate geometry to nine Er atoms. In the third Te site, Te is bonded in a 9-coordinate geometry to nine Er atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Layered Double Hydroxide Derivatives for Polyolefin Upcycling

While Ru-catalyzed hydrogenolysis holds significant promise in converting waste polyolefins into value-added alkane fuels, a major constraint is the high cost of noble metal catalysts. Here, in this work, we propose, for the first time, that Co-based catalysts derived from CoAl-layered double hydroxide (LDH) are alternatives for efficient polyolefin hydrogenolysis. Leveraging the chemical flexibility of the LDH platform, we reveal that metallic Co species serve as highly efficient active sites for polyolefin hydrogenolysis. Furthermore, we introduced Ni into the Co framework to tackle the issue of restricted hydrogenation ability associated with contiguous Co-Co sites. In-situ analysis indicates that the integration of Ni induces electron transfer and facilitates hydrogen spillover. This dual effect synergistically enhances the hydrogenation/desorption of olefin intermediates, resulting in a significant reduction in the yield of low-value CH 4 from 27.1 to 12.6%. Through leveraging the unique properties of LDH, we have developed efficient and cost-effective catalysts for the sustainable recycling and valorization of waste polyolefin materials.

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

Materials Data on Ru3C9Se2O9 by Materials Project

Ru3Se2(CO)9 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of eighteen formaldehyde molecules and two Ru3Se2 clusters. In each Ru3Se2 cluster, there are three inequivalent Ru+3.33+ sites. In the first Ru+3.33+ site, Ru+3.33+ is bonded in a 5-coordinate geometry to two Se2- atoms. There are one shorter (2.55 Å) and one longer (2.56 Å) Ru–Se bond lengths. In the second Ru+3.33+ site, Ru+3.33+ is bonded in a 5-coordinate geometry to two Se2- atoms. There are one shorter (2.52 Å) and one longer (2.53 Å) Ru–Se bond lengths. In the third Ru+3.33+ site, Ru+3.33+ is bonded in a 5-coordinate geometry to two Se2- atoms. There are one shorter (2.51 Å) and one longer (2.53 Å) Ru–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 4-coordinate geometry to three Ru+3.33+ atoms. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ru+3.33+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Data-Driven Discovery of Bimetallic Nanoparticles Catalysts for the Hydrogenolysis of Polyethylene

Supported platinum nanoparticles are known to convert polyolefins to high-quality liquid hydrocarbons with hydrogen under relatively mild conditions. However, no systematic study has been undertaken using bimetallic catalysts for polyethylene upcycling. Specifically, a total of 98 monometallic and bimetallic combinations (Ag, Cr, Co, Cu, Fe, Ga, In, Mn, Ni, Pd, Pt, Rh, Ru, Zr) on alumina were synthesized utilizing surface organometallic chemistry (SOMC) technique via robotic platform. These were investigated at a small scale (10 mg of catalyst and 50 mg of polyethylene) for their activity for the hydrogenolysis of polyethylene in a high-throughput batch reactor. Combinations of Ni and Co were selected as candidates with high activity toward conversion into paraffin oils. Reaction conditions were optimized with Ni/Co/Al 2 O 3 catalyst at a larger scale (300 mg catalyst and 3 g polyethylene) to obtain a high yield (93.1%) of paraffin wax with desired properties (M n = 380 Da) and low polydispersity (Đ = 1.2). Ni/Co/Al 2 O 3 was compared against Co/Ni/Al 2 O 3 to understand the role of the deposition sequence. When Co is deposited before Ni, a layer of cobalt aluminate is formed upon reduction, stabilizing the deposition of 5 nm metallic Ni particles. When nickel is deposited before Co, particles are larger (average >20 nm) and more oxidized (Ni δ+ in NiAl 2 O 4 ), decreasing the availability of the catalytically active metallic Ni. In conclusion, the difference in electronic environments was also described by DFT calculations, which revealed that smaller 3D clusters of Ni are preferred on CoAl2O4 over the 3D clusters on NiAl 2 O 4 and that these smaller clusters are more reducible, as confirmed experimentally.

Polymer↗
DOE OSTI2020

Materials Data on Gd5(RuO7)2 by Materials Project

Gd5(RuO7)2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Gd sites. In the first Gd site, Gd is bonded to seven O atoms to form distorted GdO7 pentagonal bipyramids that share corners with two RuO6 octahedra, corners with three equivalent GdO7 pentagonal bipyramids, edges with two RuO6 octahedra, and edges with two equivalent GdO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 30–37°. There are a spread of Gd–O bond distances ranging from 2.21–2.51 Å. In the second Gd site, Gd is bonded in a distorted square co-planar geometry to eight O atoms. There are four shorter (2.25 Å) and four longer (2.82 Å) Gd–O bond lengths. There are two inequivalent Ru sites. In the first Ru site, Ru is bonded to six O atoms to form RuO6 octahedra that share corners with two equivalent RuO6 octahedra, corners with four equivalent GdO7 pentagonal bipyramids, and edges with four equivalent GdO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 39°. There is four shorter (1.91 Å) and two longer (2.02 Å) Ru–O bond length. In the second Ru site, Ru is bonded to six O atoms to form RuO6 octahedra that share corners with two equivalent RuO6 octahedra, corners with four equivalent GdO7 pentagonal bipyramids, and edges with four equivalent GdO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 39°. There is four shorter (1.90 Å) and two longer (2.00 Å) Ru–O bond length. There are four inequivalent O sites. In the first O site, O is bonded in a trigonal planar geometry to three Gd atoms. In the second O site, O is bonded in a 4-coordinate geometry to three Gd and one Ru atom. In the third O site, O is bonded in a 3-coordinate geometry to two equivalent Gd and one Ru atom. In the fourth O site, O is bonded to two equivalent Gd and two Ru atoms to form distorted corner-sharing OGd2Ru2 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2022

CH 4 steam reforming on Pt + Pd/Al 2 O 3 monolith: impact of Mn 0.5 Fe 2.5 O 4 spinel addition

The performance of Pt + Pd/Al 2 O 3 monolith catalysts was analyzed under a feed (H 2 + CO + CH 4 + NO + O 2 + H 2 O + CO 2 ) simulating the exhaust gas of stoichiometric natural gas vehicles (NGVs). The flow reactor results show enhanced low temperature (<400 °C) CH 4 oxidation activity under cyclic lean/rich feed modulation and with Mn 0.5 Fe 2.5 O 4 (MFO) spinel addition to the platinum group metal (PGM) catalyst. In the absence of the MFO spinel, the PGM catalyst can achieve full CH 4 conversion, but the presence of spinel in the catalyst limits the high temperature (>500 °C) CH 4 conversion. The depletion of gas phase O 2 , as indicated by the detection of products CO and H 2 in the reactor effluent at higher temperature and CH 4 conversion, portends the emergence of steam reforming of CH 4 (SRM). To investigate the cause of the detrimental impact of spinel under the high temperature, net rich regime, we show through a combination of SRM experiments and post-reaction catalyst characterization that SRM is negatively impacted by the accumulation of Mn and Fe spinel species on the PGM catalyst. This is due to the migration of the base metal species and potential encapsulation and blockage of PGM active sites. The latter is supported by density functional theory (DFT) calculations that indicate favorable metal oxide decoration of active Pt step sites. Lastly, a zoned catalyst design is developed that mitigates the detrimental metals migration while exploiting the methane conversion enhancement afforded by spinel oxides under oxygen rich conditions.

03 NATURAL GAS↗
DOE OSTI2021

Simultaneous electrocatalytic hydrogenation of aldehydes and phenol over carbon-supported metals

Electrocatalytic hydrogenation of furfural, benzaldehyde, and phenol was studied on carbon-supported Rh, Ru, Pd, and Cu catalysts. All metals were active for hydrogenation of the carbonyl group in furfural and benzaldehyde, but only Rh/C was active for phenol hydrogenation. The intrinsic activities for furfural and benzaldehyde conversion were Pd/C < Ru/C ? Rh/C < Cu/C and Ru/C < Rh/C < Pd/C < Cu/C, respectively. While the trend in furfural hydrogenation remained the same in the presence of phenol, the trend in benzaldehyde hydrogenation in the presence of phenol changed to Rh/C < Ru/C < Pd/C < Cu/C. The Faradaic efficiencies for hydrogenation of both furfural (in the 10–40% range) and benzaldehyde (in the 45–100% range) followed the trend: Cu/C < Rh/C < Ru/C < Pd/C. When phenol and an aldehyde were present in the reactant solution, phenol hydrogenation (only observed on Rh) was suppressed. In contrast, enhancements in the rates of carbonyl reduction were observed for both aldehydes in presence of phenol. Such enhancements depend on both the aldehyde and the metal catalyst. The enhancing factors for hydrogenation of furfural and benzaldehyde were in the 1.5–2 and 2–4 ranges, respectively. We conclude that intermolecular interactions between adsorbed phenol and the aldehydes is a general phenomenon that can potentially enhance the rates of carbonyl hydrogenation. This work highlights co-adsorption effects that pose both challenges and advantages for electrocatalytic reduction of organic compounds.

Electrocatalytic hydrogenation, metal catalysts, p↗
DOE OSTI2020

Materials Data on Ba2CoRuO6 by Materials Project

Ba2CoRuO6 is (Cubic) Perovskite-derived structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are six inequivalent Ba2+ sites. In the first 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 three equivalent RuO6 octahedra, and faces with five CoO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.84–2.97 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 BaO12 cuboctahedra, faces with two CoO6 octahedra, and faces with six RuO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.87–2.93 Å. In the third 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 RuO6 octahedra, and faces with four CoO6 octahedra. The corner-sharing octahedral tilt angles are 15°. There are a spread of Ba–O bond distances ranging from 2.88–2.94 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, a faceface with one RuO6 octahedra, and faces with six CoO6 octahedra. The corner-sharing octahedra tilt angles range from 11–12°. There are a spread of Ba–O bond distances ranging from 2.88–3.02 Å. In the fifth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent CoO6 octahedra, faces with seven BaO12 cuboctahedra, faces with three equivalent CoO6 octahedra, and faces with four RuO6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are a spread of Ba–O bond distances ranging from 2.87–3.00 Å. In the sixth 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 CoO6 octahedra, and faces with four RuO6 octahedra. The corner-sharing octahedral tilt angles are 14°. There are a spread of Ba–O bond distances ranging from 2.89–2.92 Å. There are three inequivalent Ru6+ sites. In the first Ru6+ site, Ru6+ is bonded to six O2- atoms to form RuO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent CoO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one RuO6 octahedra. The corner-sharing octahedra tilt angles range from 3–4°. There is three shorter (1.94 Å) and three longer (2.05 Å) Ru–O bond length. In the second Ru6+ site, Ru6+ is bonded to six O2- atoms to form RuO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent CoO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one RuO6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are a spread of Ru–O bond distances ranging from 1.94–2.04 Å. In the third Ru6+ site, Ru6+ is bonded to six O2- atoms to form RuO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent CoO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one CoO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Ru–O bond distances ranging from 1.95–1.97 Å. There are three inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with three equivalent RuO6 octahedra, corners with three equivalent CoO6 octahedra, and faces with eight BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 3–6°. There are a spread of Co–O bond distances ranging from 2.01–2.17 Å. In the second Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six RuO6 octahedra and faces with eight BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Co–O bond distances ranging from 2.06–2.14 Å. In the third Co2+ site, Co2+ is bonded to six O2- atoms to form distorted CoO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent CoO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one RuO6 octahedra. The corner-sharing octahedra tilt angles range from 5–6°. There are a spread of Co–O bond distances ranging from 1.86–2.12 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Ru6+, and one Co2+ atom. In the second O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Ru6+, and one Co2+ atom. In the third O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Ru6+, and one Co2+ atom. In the fourth O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Ru6+, and one Co2+ atom. In the fifth O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Ru6+, and one Co2+ atom. In the sixth O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Ru6+, and one Co2+ atom. In the seventh O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two Co2+ atoms. In the eighth O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two Co2+ atoms. In the ninth O2- site, O2- is bonded in a 6-coordinate geometry to four Ba2+, one Ru6+, and one Co2+ atom. In the tenth O2- site, O2- is bonded to four Ba2+, one Ru6+, and one Co2+ atom to form distorted corner-sharing OBa4CoRu octahedra. The corner-sharing octahedral tilt angles are 7°. In the eleventh O2- site, O2- is bonded in a 6-coordinate geometry to four Ba2+ and two Ru6+ atoms. In the twelfth O2- site, O2- is bonded in a 6-coordinate geometry to four Ba2+ and two Ru6+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H15PdRuN9O11 by Materials Project

Pd(NO2)4RuN5H13O2H2O crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of two water molecules, two Pd(NO2)4 clusters, and two RuN5H13O2 clusters. In one of the Pd(NO2)4 clusters, Pd4+ is bonded in a square co-planar geometry to four N+0.33- atoms. There are two shorter (2.05 Å) and two longer (2.06 Å) Pd–N bond lengths. There are two inequivalent N+0.33- sites. In the first N+0.33- site, N+0.33- is bonded in a trigonal planar geometry to one Pd4+ and two O2- atoms. There is one shorter (1.24 Å) and one longer (1.26 Å) N–O bond length. In the second N+0.33- site, N+0.33- is bonded in a trigonal planar geometry to one Pd4+ and two O2- atoms. Both N–O bond lengths are 1.25 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one N+0.33- atom. In the second O2- site, O2- is bonded in a single-bond geometry to one N+0.33- atom. In the third O2- site, O2- is bonded in a single-bond geometry to one N+0.33- atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one N+0.33- atom. In one of the Pd(NO2)4 clusters, Pd4+ is bonded in a square co-planar geometry to four N+0.33- atoms. There are two shorter (2.05 Å) and two longer (2.06 Å) Pd–N bond lengths. There are two inequivalent N+0.33- sites. In the first N+0.33- site, N+0.33- is bonded in a trigonal planar geometry to one Pd4+ and two O2- atoms. Both N–O bond lengths are 1.25 Å. In the second N+0.33- site, N+0.33- is bonded in a trigonal planar geometry to one Pd4+ and two O2- atoms. There is one shorter (1.25 Å) and one longer (1.26 Å) N–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one N+0.33- atom. In the second O2- site, O2- is bonded in a single-bond geometry to one N+0.33- atom. In the third O2- site, O2- is bonded in a single-bond geometry to one N+0.33- atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one N+0.33- atom. In each RuN5H13O2 cluster, Ru6+ is bonded in an octahedral geometry to five N+0.33- and one O2- atom. There is one shorter (1.75 Å) and four longer (2.13 Å) Ru–N bond length. The Ru–O bond length is 1.99 Å. There are five inequivalent N+0.33- sites. In the first N+0.33- site, N+0.33- is bonded in a linear geometry to one Ru6+ and one O2- atom. The N–O bond length is 1.17 Å. In the second N+0.33- site, N+0.33- is bonded in a trigonal non-coplanar geometry to one Ru6+ and three H1+ atoms. All N–H bond lengths are 1.03 Å. In the third N+0.33- site, N+0.33- is bonded in a distorted trigonal non-coplanar geometry to one Ru6+ and three H1+ atoms. All N–H bond lengths are 1.03 Å. In the fourth N+0.33- site, N+0.33- is bonded in a distorted trigonal non-coplanar geometry to one Ru6+ and three H1+ atoms. There is one shorter (1.02 Å) and two longer (1.03 Å) N–H bond length. In the fifth N+0.33- site, N+0.33- is bonded in a trigonal non-coplanar geometry to one Ru6+ and three H1+ atoms. All N–H bond lengths are 1.03 Å. There are thirteen inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N+0.33- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one N+0.33- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one N+0.33- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one N+0.33- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one N+0.33- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one N+0.33- atom. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one N+0.33- atom. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one N+0.33- atom. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one N+0.33- atom. In the eleventh H1+ site, H1+ is bonded in a single-bond geometry to one N+0.33- atom. In the twelfth H1+ site, H1+ is bonded in a single-bond geometry to one N+0.33- atom. In the thirteenth H1+ site, H1+ is bonded in a single-bond geometry to one N+0.33- atom. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one Ru6+ and one H1+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one N+0.33- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Post-irradiation examination of commercial tantalum alloys following neutron irradiation

Post irradiation examination of two commercial tantalum alloys (based on Ta-8 %W) revealed significant irradiation hardening following neutron irradiation in the High Flux Isotope Reactor at Oak Ridge National Laboratory. Tensile samples of commercial Ta alloys T-111 and ASTAR-811C were irradiated to a total neutron fluence (E > 0.1 MeV) in the range (2–4)x10 21 n/cm 2 (0.39–0.75 dpa) at an irradiation temperature near 900 °C. Tensile testing conducted at room temperature and at 800 °C revealed significant irradiation hardening under all test conditions. Samples that were tensile tested at room temperature exhibited brittle failure, whereas ductility was maintained for elevated temperature testing. The irradiation hardening and embrittlement noted for both alloys was attributed to irradiation-induced dislocation loop formation as confirmed through scanning transmission electron microscopy analysis. Corresponding energy dispersive x-ray spectroscopy revealed radiation-induced segregation of Hf in these loop populations. This Hf enrichment is shown to result in eventual co-precipitation of elongated (Hf,O)-rich precipitates along the dislocation loops. Further, these results show that irradiation hardening is enhanced via irradiation-enhanced precipitation at elevated irradiation temperatures. Consequently, the minimum recommended operating temperature window for Ta alloys should be increased to account for observed hardening/embrittlement at irradiation temperatures as high as 900 °C (1,173 K).

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CoHRu3(CO)13 by Materials Project

RuRu2HCo(CO)4(CO)9 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of thirty-six formaldehyde molecules, four ruthenium molecules, four Co(CO)4 clusters, and four Ru2H clusters. In each Co(CO)4 cluster, Co2+ is bonded in a distorted trigonal pyramidal geometry to four C+0.92+ atoms. There are a spread of Co–C bond distances ranging from 1.75–1.89 Å. There are four inequivalent C+0.92+ sites. In the first C+0.92+ site, C+0.92+ is bonded in a distorted bent 150 degrees geometry to one Co2+ and one O2- atom. The C–O bond length is 1.18 Å. In the second C+0.92+ site, C+0.92+ is bonded in a linear geometry to one Co2+ and one O2- atom. The C–O bond length is 1.16 Å. In the third C+0.92+ site, C+0.92+ is bonded in a distorted single-bond geometry to one Co2+ and one O2- atom. The C–O bond length is 1.18 Å. In the fourth C+0.92+ site, C+0.92+ is bonded in a distorted single-bond geometry to one Co2+ and one O2- atom. The C–O bond length is 1.18 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one C+0.92+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one C+0.92+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one C+0.92+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one C+0.92+ atom. In each Ru2H cluster, Ru+3.67+ is bonded in a 1-coordinate geometry to one H1+ atom. The Ru–H bond length is 1.80 Å. H1+ is bonded in a bent 120 degrees geometry to two equivalent Ru+3.67+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H2Ru6C18SO20 by Materials Project

(Ru)2Ru4H2SO2(CO)18 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of thirty-six formaldehyde molecules, four ruthenium molecules, and two Ru4H2SO2 clusters. In each Ru4H2SO2 cluster, there are four inequivalent Ru+2.67+ sites. In the first Ru+2.67+ site, Ru+2.67+ is bonded in a distorted single-bond geometry to one S2- and one O2- atom. The Ru–S bond length is 2.49 Å. The Ru–O bond length is 2.17 Å. In the second Ru+2.67+ site, Ru+2.67+ is bonded in a distorted L-shaped geometry to one S2- and one O2- atom. The Ru–S bond length is 2.51 Å. The Ru–O bond length is 2.15 Å. In the third Ru+2.67+ site, Ru+2.67+ is bonded in a distorted single-bond geometry to one S2- and one O2- atom. The Ru–S bond length is 2.48 Å. The Ru–O bond length is 2.17 Å. In the fourth Ru+2.67+ site, Ru+2.67+ is bonded in a distorted L-shaped geometry to one S2- and one O2- atom. The Ru–S bond length is 2.52 Å. The Ru–O bond length is 2.15 Å. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. S2- is bonded in a 4-coordinate geometry to four Ru+2.67+ atoms. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to two Ru+2.67+ and one H1+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two Ru+2.67+ and one H1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Computational Investigations of the Reactivity of Metalloporphyrins for Ammonia Oxidation

Density functional theory and molecular dynamics simulations were used to assess the ability of tetraphenylporphyrin (TPP)M complexes (where M = Cr, Mn, Fe, Co, Ni, Mo, Ru, W, and Os) to coordinate and weaken the N-H bonds of ammonia, as well as their reactivity towards N-N bond formation for N 2 generation. Compared to other metalloporphyrins, bis-ammonia complexes (TPP)Mo(NH 3 ) 2 and (TPP)W(NH 3 ) 2 exhibit low and level N-H BDFEs due to a stabilized (TPP)M(NH 3 )(NH) intermediate by multiple metal-ligand bonding. These results resemble those previously obtained for polypyridyl metal complexes, suggesting that broad trends in reactivity towards N-H bond cleavage are more metal-dependent rather than ligand-dependent for a metal in a nitrogen pseudo-octahedral environment. We investigated N-N bond formation via NH 3 nucleophilic attack on M-NH and M-N intermediates, compared to bimolecular coupling of M-NH x intermediates. We evaluated the reactivity of (TPP)Fe(NH 3 ) 2 towards N-N bond formation via a hydrazine pathway, and found amide-amide coupling to form a bridged hydrazido complex to be the most favorable pathway for N-N bond formation. Further investigation of possible N-N bond formation pathways by reaction with NH 3 led us to identify a possible Fe III -•NH species with significant aminyl character that bypasses the nucleophilic attack of NH 3 and that promotes homolytic N-H bond cleavage of ammonia. This reaction forms a Fe-NH 2 moiety and a transient •NH 2 radical that subsequently forms an N-N bond with the Fe-NH 2 moiety to form a (TPP)Fe(NH 3 )(N 2 H 4 ) species. Furthermore, these results indicate the need to evaluate the radical character of imido species and their reactivity towards N-H bond cleavage of ammonia.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗