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RuNCl2N2(NO)2NCl crystallizes in the orthorhombic Pna2_1 space group. The structure is zero-dimensional and consists of four chloramine molecules, four dichloro(imino)ruthenium molecules, four nitrogen molecules, and eight nitroxyl molecules.
(Ru)5NiCOC(CO)15 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of thirty formaldehyde molecules; two methane molecules; two nickel, hydroxymethyl- molecules; and ten ruthenium molecules.
SrRuO3 crystallizes in the orthorhombic Pnma space group. The structure is zero-dimensional and consists of four hydrogen peroxide molecules, four ruthenium molecules, four strontium molecules, and four water molecules.
KTb(CN)6Ru(O2)2 crystallizes in the orthorhombic Cmcm space group. The structure is two-dimensional and consists of four 1,2,3,4-tetraoxacyclobutane molecules; four ruthenium molecules; and two KTb(CN)6 sheets oriented in the (0, 0, 1) direction. In each KTb(CN)6 sheet, K1+ is bonded in a 6-coordinate geometry to six N3- atoms. There are two shorter (2.88 Å) and four longer (2.97 Å) K–N bond lengths. Tb3+ is bonded in a distorted pentagonal pyramidal geometry to six N3- atoms. There are four shorter (2.37 Å) and two longer (2.46 Å) Tb–N bond lengths. There are two inequivalent C+2.67+ sites. In the first C+2.67+ site, C+2.67+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. In the second C+2.67+ site, C+2.67+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a 2-coordinate geometry to one K1+, one Tb3+, and one C+2.67+ atom. In the second N3- site, N3- is bonded in a distorted linear geometry to one K1+, one Tb3+, and one C+2.67+ atom.
Ru(Ru(NO)2)2(N2Cl)2(N2OCl3)2 crystallizes in the orthorhombic Immm space group. The structure is one-dimensional and consists of two ruthenium molecules; four N2Cl clusters; four Ru(NO)2 clusters; and two N2OCl3 ribbons oriented in the (1, 0, 0) direction. In each N2Cl cluster, N+0.33+ is bonded in a single-bond geometry to one Cl1- atom. The N–Cl bond length is 1.57 Å. Cl1- is bonded in a distorted bent 120 degrees geometry to two equivalent N+0.33+ atoms. In each Ru(NO)2 cluster, Ru+5.33+ is bonded in a distorted tetrahedral geometry to two equivalent N+0.33+ and two equivalent O2- atoms. Both Ru–N bond lengths are 1.72 Å. Both Ru–O bond lengths are 1.82 Å. N+0.33+ is bonded in a distorted single-bond geometry to one Ru+5.33+ atom. O2- is bonded in a single-bond geometry to one Ru+5.33+ atom. In each N2OCl3 ribbon, N+0.33+ is bonded in an L-shaped geometry to two equivalent Cl1- atoms. Both N–Cl bond lengths are 1.80 Å. O2- is bonded in a distorted single-bond geometry to one O2- and four Cl1- atoms. The O–O bond length is 1.22 Å. There are two shorter (2.93 Å) and two longer (2.94 Å) O–Cl bond lengths. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a distorted L-shaped geometry to two equivalent N+0.33+ and one O2- atom. In the second Cl1- site, Cl1- is bonded in a distorted bent 150 degrees geometry to two equivalent O2- atoms.
RuNa4N6O13 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional and consists of four ruthenium molecules and one Na4N6O13 framework. In the Na4N6O13 framework, there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form distorted NaO6 pentagonal pyramids that share corners with two equivalent NaO7 pentagonal bipyramids, a cornercorner with one NaO6 pentagonal pyramid, and edges with two equivalent NaO7 pentagonal bipyramids. There are a spread of Na–O bond distances ranging from 2.35–2.57 Å. In the second Na1+ site, Na1+ is bonded to seven O2- atoms to form distorted NaO7 pentagonal bipyramids that share corners with two equivalent NaO6 pentagonal pyramids, an edgeedge with one NaO7 pentagonal bipyramid, and edges with two equivalent NaO6 pentagonal pyramids. There are a spread of Na–O bond distances ranging from 2.39–2.54 Å. There are three inequivalent N3+ sites. In the first N3+ site, N3+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.25 Å) and one longer (1.27 Å) N–O bond length. In the second N3+ site, N3+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both N–O bond lengths are 1.26 Å. In the third N3+ site, N3+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.25 Å) and one longer (1.27 Å) N–O bond length. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two Na1+ and one N3+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Na1+ and one N3+ atom. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent Na1+ atoms. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+ and one N3+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Na1+ and one N3+ atom. In the sixth O2- site, O2- is bonded in a trigonal planar geometry to two Na1+ and one N3+ atom. In the seventh O2- site, O2- is bonded to three Na1+ and one N3+ atom to form distorted edge-sharing ONa3N trigonal pyramids.
RuTeTe5Br8 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four ruthenium molecules, four tellurium molecules, and four Te5Br8 clusters. In each Te5Br8 cluster, there are five inequivalent Te1+ sites. In the first Te1+ site, Te1+ is bonded in a single-bond geometry to one Br1- atom. The Te–Br bond length is 3.16 Å. In the second Te1+ site, Te1+ is bonded in a single-bond geometry to one Br1- atom. The Te–Br bond length is 3.04 Å. In the third Te1+ site, Te1+ is bonded in a rectangular see-saw-like geometry to four Br1- atoms. There are a spread of Te–Br bond distances ranging from 2.59–3.05 Å. In the fourth Te1+ site, Te1+ is bonded in a distorted rectangular see-saw-like geometry to four Br1- atoms. There are a spread of Te–Br bond distances ranging from 2.56–3.34 Å. In the fifth Te1+ site, Te1+ is bonded in a T-shaped geometry to three Br1- atoms. There are a spread of Te–Br bond distances ranging from 2.59–2.78 Å. There are eight inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a single-bond geometry to one Te1+ atom. In the second Br1- site, Br1- is bonded in an L-shaped geometry to two Te1+ atoms. In the third Br1- site, Br1- is bonded in a single-bond geometry to one Te1+ atom. In the fourth Br1- site, Br1- is bonded in a distorted L-shaped geometry to two Te1+ atoms. In the fifth Br1- site, Br1- is bonded in a distorted single-bond geometry to two Te1+ atoms. In the sixth Br1- site, Br1- is bonded in a single-bond geometry to one Te1+ atom. In the seventh Br1- site, Br1- is bonded in a 2-coordinate geometry to two Te1+ atoms. In the eighth Br1- site, Br1- is bonded in a 2-coordinate geometry to two Te1+ atoms.
(Li(H2O)4)3RuCl6 is Tungsten Carbide-like structured and crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of four ruthenium(6+) hexachloride molecules and four Li(H2O)4 clusters. In each Li(H2O)4 cluster, there are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to six O2- atoms to form face-sharing LiO6 octahedra. There are a spread of Li–O bond distances ranging from 2.16–2.19 Å. In the second Li1+ site, Li1+ is bonded to six O2- atoms to form face-sharing LiO6 octahedra. There are two shorter (2.14 Å) and four longer (2.16 Å) Li–O bond lengths. There are twelve 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 0.98 Å. In the third 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 fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fifth 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 sixth 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 seventh 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 eighth 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 ninth 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 tenth 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 eleventh 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 twelfth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to one Li1+ and two H1+ atoms. In the second O2- site, O2- is bonded in a distorted water-like geometry to one Li1+ and two H1+ atoms. In the third O2- site, O2- is bonded in a distorted water-like geometry to one Li1+ and two H1+ atoms. In the fourth O2- site, O2- is bonded in a distorted water-like geometry to two Li1+ and two H1+ atoms. In the fifth O2- site, O2- is bonded in a distorted water-like geometry to two Li1+ and two H1+ atoms. In the sixth O2- site, O2- is bonded in a distorted water-like geometry to two Li1+ and two H1+ atoms.
Nuclei with equal number of baryons but varying proton number (isobars) have many commonalities, but differ in both electric charge and nuclear structure. Relativistic collisions of such isobars provide unique opportunities to study the variation of the magnetic field, provided the nuclear structure is well understood. In this work we simulate collisions using several state-of-the-art parametrizations of the ^{96}_{40} 40 96 Zr and ^{96}_{44} 44 96 Ru isobars and show that a comparison with the exciting STAR measurement [arXiv:2109.00131] of ultrarelativistic collisions can uniquely identify the structure of both isobars. This not only provides an urgently needed understanding of the structure of the Zirconium and Ruthenium isobars, but also paves the way for more detailed studies of nuclear structure using relativistic heavy ion collisions.
The Defense Waste Processing Facility (DWPF) began processing Sludge Batch 7b (SB7b), also referred to as Macrobatch 9 (MB9), in January 2012. SB7b is a blend of the heel of Tank 40 from Sludge Batch 7a (SB7a) and the SB7b material that was transferred to Tank 40 from Tank 51. SB7b was processed using Frit 418. During processing of each sludge batch, the DWPF is required to take at least one glass sample to meet the objectives of the Glass Product Control Program (GPCP), which is governed by the DWPF Waste Form Compliance Plan, and to complete the necessary Production Records so that the final glass product may be disposed of at a Federal Repository. Two pour stream glass samples were collected while processing SB7b. The samples were transferred to the Savannah River National Laboratory (SRNL) where one was analyzed and the other was archived. The following conclusions were drawn from the analytical results provided in this report: The sum of oxides for the official SB7b pour stream glass is within the Product Composition Control System (PCCS) limits (95-105 wt%); The average calculated Waste Dilution Factor (WDF) for SB7b is 2.3. In general, the measured radionuclide content of the official SB7b pour stream glass is in good agreement with the calculated values from the Tank 40 dried sludge results from the SB7b Waste Acceptance Program Specification (WAPS) sample; As in previous pour stream samples, ruthenium and rhodium inclusions were detected by Scanning Electron Microscopy-Electron Dispersive Spectroscopy (SEM-EDS) in the SB7b pour stream sample; The Product Consistency Test (PCT) results indicate that the official SB7b pour stream glass meets the waste acceptance criteria for durability with a normalized boron release of 0.8 g/L, which is an order of magnitude less than the Environmental Assessment (EA) glass; The measured density of the SB7b pour stream glass was 2.70 g/cm 3 ; The Fe 2+ /ΣFe ratio of the SB7b pour stream samples was 0.07.
The conversions of nitrite to nitrate, the destruction of glycolate, and the conversion of glycolate to formate and oxalate were modeled for the Nitric-Glycolic flowsheet using data from Chemical Process Cell (CPC) simulant runs conducted by Savannah River National Laboratory (SRNL) from 2011 to 2016. The goal of this work was to develop empirical correlation models to predict these values from measurable variables from the chemical process so that these quantities could be predicted a-priori from the sludge or simulant composition and measurable processing variables. The need for these predictions arises from the need to predict the REDuction/OXidation (REDOX) state of the glass from the Defense Waste Processing Facility (DWPF) melter. This report summarizes the work on these correlations based on the aforementioned data. Previous work on these correlations was documented in a technical report covering data from 2011-2015. This current report supersedes this previous report. Further refinement of the models as additional data are collected is recommended. The glass REDOX depends on the concentrations of nitrate and manganese (oxidants), and of glycolate, formate, oxalate, carbon, and antifoam (reductants) in the melter feed. The waste sludge contains nitrite, nitrate, manganese (Mn), and oxalate. Virtually all of the nitrite is converted to nitrate or NO+NO 2 +N 2 O gases in the CPC. The portion of the nitrite converted to nitrate increases the amount of nitrate in the sludge. The amount of glycolate in the final melter feed depends on the amount of the glycolic acid feed that is destroyed. Similarly, the amounts of formate and oxalate formed during the decomposition of glycolic acid are required. The material balance on carbon was found to not close in most cases. Generally, there was less carbon at the end of testing compared to the inputs. The most uncertain product variable was glycolate, so material balances were performed where the glycolate concentration was adjusted, usually upward, to close the balance. Correlation versus the original, as-measured, data was generally poor, but correlation against the material balance adjusted values was greatly improved. It was also shown that the correlation of the measured REDOX versus the predicted REDOX was much better when the material balance adjusted glycolate values were used. Three data series were primarily used during the regressions of the data; these series were 1) Sludge Batch 9 NG flowsheet simulant runs NG51-62 (SB9-NG); 2) Scaled Runs + Bounding Hydrogen Runs (SR+BH); and 3) Runs GN43-50 and 57 (43-50,57). The glycolate destruction was found to correlate with acid stoichiometry (AS), percent reducing acid (PRA), and for some data series, headspace to simulant volume ratio (HSV), mercury (Hg), and nitrate. Although glycolate destruction for pairs of data series (e.g., [SB9-NG] and [SR+BH]) were found to depend on HSV, the combination of all three data series was not found to have significant dependence on this variable. The best model for glycolate destruction depended on AS, nitrate, and Hg. This model predicted the product glycolate compositions of the data to within 92-106%. The conversion of glycolate to formate was high when noble metals and Hg were not present, with values up to 100%. When noble metals and Hg were present, this conversion ranged from zero to 7%, and was dependent on AS. Lower AS gave higher conversions to formate. The conversion to oxalate was found to depend on the AS and the initial concentration of nitrite. An alternative fit versus AS and the form of ruthenium (Ru) used is a possible alternative. This fit was somewhat less statistically significant. This second model predicts that more oxalate is formed when Ru-nitrosyl nitrate is used rather than Ru chloride. The conversion of glycolate to oxalate ranged from zero to 6%. The conversion of nitrite to nitrate depended primarily on AS and PRA, with HSV and Hg being significant when these variables were varied. For multiple series of data, nitrite was also needed to SRNL-STI-2017-00172 5HYLVLRQ viL distinguish between data series, and the effect of HSV became insignificant. The best model for nitrite to nitrate conversion depended on AS, PRA, nitrite, and Hg. The 95% confidence intervals on the predicted values of glycolate destruction, glycolate to oxalate conversion, and nitrite to nitrate conversion were used to determine the uncertainty in the predicted REDOX when starting with only the composition of the sludge, AS, and PRA. Using the 95% confidences on an individual value (that is the confidence in getting a particular value for one single test as opposed to what the mean would be for multiple tests), the uncertainty in the predicted REDOX was calculated. The uncertainty in the actual product composition glycolate, oxalate, formate, and nitrate concentrations translated to an uncertainty in the REDOX value of ±0.1,which is approximately the uncertainty claimed in the REDOX model itself.
Recent advancements in carbon nanotube (CNT) research have enabled lightweight, conductive wires as a transformative technology. Metal-carbon nanotube (CNT) hybrid conductors aim to combine the high conductivity of traditional metals with the low mass and temperature coefficient of resistance (TCR) of carbon nanotubes. The high conductivity of copper makes it a promising candidate to combine with CNTs in a hybrid structure, but there is limited physical and electrical interaction between copper and CNTs. The use of an interfacial layer offers one method of improving the interconnection of a Cu-CNT hybrid conductor. Over the course of this grant, a joule heating-driven chemical vapor deposition (CVD) technique was developed to deposit nanometal seeds throughout a porous, low-density (0.12 g/cm 3 , ~10 tex or mg/m) CNT roving template. Modification of the applied current to the CNT roving allows for the tuning of depositions towards either hot-spot site-specificity or overall uniformity. The effects of temperature, pressure, precursor mass, and the interval of applied current were investigated, demonstrating nanometal depositions ranging from less than 5 % w/w to over 85 % w/w. The versatility of CVD allows for a wide variety of metals to be deposited including copper, titanium, nickel, silver, tungsten, palladium, platinum, ruthenium, rhodium, and iridium. One preferred demonstration involved using platinum depositions to improve the electrical properties of metal-seeded CNTs across all mass loadings studied. Moreover, when the metal-seeded CNT wires were electroplated with copper, densified, and annealed under hydrogen/argon; the result was a Cu-CNT hybrid conductor with the highest conductivities reported to date. The good interconnection of the metal and CNT portions results in a stable conductor. An electrical conductivity of 16-20 MS/m was achieved for multiple Cu-CNT hybrid conductors at 150 °C, which exceeds the program goal for conductivity of greater than 15 MS/m for a 1 m long CNT wire. Overall, the research outcomes from the project showed improvements in CNT wire fabrication from roll-to-roll CVD grown carbon nanotube wires using nanometal interconnects to bridge CNT-to-CNT junctions, thus mitigating network contact resistances. Advanced nanometal interconnected carbon conductors (NICCs) were developed as a means to achieve novel light-weight wiring appropriate for applications that require the conductivity of metallic (i.e., Cu, Al, etc.) wires at elevated temperatures. High conductivity, low TCR electrical conductors such as the nanometal interconnected Cu-CNT hybrids have numerous future applications towards high efficiency motors, generators, and transformers. Specifically, the advanced wires have the ability to operate at lower resistance during conditions for standard electric motors at 150 °C, which would improve the electrical efficiency while lowering energy needs.
To fulfill the design and licensing requirements for advanced reactors, the U.S. Department of Energy (DOE) is specifically interested in targeted research to quantify the mechanisms of fission product transport and retention in graphitic grades that will likely be used in next-generation very/high temperature reactors, fluoride salt-cooled high temperature reactors and molten salt reactors. We have examined an integrated experimental-computational approach to determine the diffusivities of selected fission products – ruthenium (Ru) and silver (Ag) in five nuclear graphite grades – POCO AXF-5Q, POCO ZXF-5Q, PCEA, IG110, and NBG-18. Experimental investigation for diffusion of other fission products (iodine, cesium, and krypton) in graphite could not be carried out due to extreme evaporation due to high vapor pressure, despite several attempts incorporating various experimental schemes. Experimental investigation with irradiated graphite could not be carried out because necessary approval to transport irradiated graphite could not be obtained due to procedural reasons at ORNL and national policy change in UK. An effort was made to “produce” by ion sputtering, but it was discontinued because the outcome did not adequately represent irradiated graphite. Thin film and “cup-and-cap” methods were employed to deposit fission products, diffusion annealed were carried out in an argon atmosphere, and concentration profiles were determined by dynamic secondary ion mass spectroscopy depth profiling technique. Regardless of graphite type, anomalous diffusion behavior of Ru (i.e., lower than expected based on Arrhenius temperature dependence) at an intermediate temperature, around 600 to 700 °C, was observed. Diffusion behavior of silver on the other hand agreed well to the Arrhenius temperature dependence although the excessive evaporation of silver hampered the accurate determination of diffusivities at temperature higher than 900 °C. In general, silver was observed to diffuse faster than Ru in the temperature range compared from 500 to 900 °C, had consistently had higher pre-exponential factor corresponding to higher jump frequency. To understand the abnormal diffusional behavior of Ru in graphite in intermediate temperature range, a detailed microstructural analysis was carried out. Clustering of Ru into particles on the surface of graphite was observed around 700 °C corresponding to de-wetting and spheroidization. This change would influence the boundary condition of diffusion, although features of clustering was much smaller (<1 mm) than the SIMS raster size (120 x 120 mm). Raman spectroscopy also demonstrated that Raman peak intensity for Ru decreased significantly for samples annealed higher than 700 °C and presence of Ru in graphite altered the crystallinity of graphite. To further elucidate the abnormal diffusion behavior observed in intermediate temperature investigated, the vibrational properties of graphene, bilayer graphene and Kr atoms in bilayer graphene were investigated with molecular dynamics. Krypton, which is a fission product, was introduced between a bilayer graphene system to evaluate (i) whether the phonon dispersion curves change with high temperature in bilayer graphene (ii) whether the addition of Kr atoms between the bilayer introduces any significant change in the vibrational properties, and (iii) whether any change in the vibrational properties can be correlated to the diffusive behavior of Kr atoms. The results show that the Kr atoms indeed exhibit an anomalous diffusive behavior at 550°C. Phonon analysis shows that a few phonon frequencies are enhanced as much as 20 to 30 % with the addition of just 0.2 at.% Kr. So, this may explain the unexpected self-diffusivity of fission products.
The central goal of this proposal was to directly visualize and quantify how electronic correlations, vibronic couplings, and local solute-solvent interactions control intramolecular electron motion on the femtosecond time scale. The proposed research program focused on solvated Ruthenium (Ru) based mixed-valence complexes, a prototypical class of transition-metal complexes, which are of significant interest for their potential applications in photochemical energy conversion. Electron movements following photochemical excitation are closely coupled with atomic/vibrational and solvent motion. To disentangle these various components requires tools designed to directly probe electron correlations and vibronic coupling (coherently coupled motions of electronic and vibrational coordinates) on the timescale of electron motion in the solution phase.
Ammonia (NH 3 ), as a promising carbon neutral liquid fuel (CNLF) and an effective H 2 source, can be synthesized from air and water (N 2 extracted from air and H 2 from water) using renewable energy sources. To produce H 2 as an intermediate, it is essential to develop effective and economic NH 3 decomposition technologies. We have been developing an innovative hollow fiber membrane reactor for high purity H 2 generation from thermal catalytic NH 3 decomposition. The objective of the proposed research is to fabricate a compact and robust prototype with high energy efficiency (>80%) to deliver high purity (>99%) H2 at high rate per volume (>0.15 g H 2 /h/cm 3 ) from NH3 decomposition at low temperature (<450 °C) and high conversion (>99%). Our overall technical approach is to effectively combine an active catalyst for NH 3 decomposition with a selective H 2 membrane separation process in a novel, compact modular system to generate high purity H 2 and simultaneously achieve high NH 3 conversion and optimize the entire system energy efficiency. This novel integrated membrane reactor design, together with low-cost, highly active Ru-based catalyst, makes it most appropriate for the project objective. The proposed applied research and development work, therefore, represents an innovative and transformational solution to H 2 generation from thermal catalytic NH 3 decomposition. During the course of our research we i) synthesized and characterized ruthenium(Ru)-based catalysts, evaluated their catalytic performance for NH 3 decomposition and optimized the catalyst composition and performance based on machine learning, ii) prepared SAPO-34, MFI membranes on α-alumina hollow fibers and measured their performance for H 2 /N 2 , H 2 /N 2 /NH 3 separation and evaluated carbon molecular sieve (CMS) and Pd/Ag membranes for H 2 /N 2 , H 2 /N 2 /NH 3 separation at different conditions, iii) designed and evaluated several types of membrane reactors for H 2 production from NH 3 decomposition, and iv) evaluated the H 2 delivery cost base on catalysts development, membrane development and membrane reactor. For 3,1,12 RuYK catalyst, H 2 productivity of 6.35 mmol/min/gcat with NH 3 conversion of 95~98% was achieved at 5 bar and 400 °C; for SAPO-34 membrane, the best membrane showed H 2 permeance of 7.56×10 -7 mol/(m 2 ∙s∙Pa) and H 2 /N 2 selectivity of 23.1 at 20 °C; For CMS and Pd/Ag membranes, both showed superior stability for 71%H 2 /24%N 2 /5%NH 3 mixture separation at 450 °C and 7 bar for over 120 h; for the membrane reactor, high H 2 purity of >99.99% with NH 3 conversion of >99.4% were achieved in Pd/Ag membrane reactor at 450 °C, and the NH 3 concentration was always below 10 ppb in H 2 product. The H 2 generation rate was calculated to be as high as 0.47 g/h/cm 3 and the energy efficiency was calculated to be 88%. The membrane reactor showed superior stability for over 370 h and high H 2 purity, H 2 production rate and NH 3 conversion. Based on calculation, the H 2 delivery cost can be as low as $3.66/kg.
This project is focused on the development of novel Mn complexes that will be useful as hydrolysis catalysts for substrates such as nitriles, esters, and amides. This Mn chemistry will provide a useful platform to develop the capabilities that are necessary to synthesize and manipulate air and moisture sensitive compounds while simultaneously exploring the novel chemistry associated a new class of low-valent metal hydroxide complexes. The primary research objective of the proposed Mn chemistry the synthesis of well-defined Mn hydroxide complexes that will use the nucleophilicity of the hydroxide ligand in an anhydrous environment as a catalyst for desirable organic transformations. Several metal-ligand combinations are explored and have been extended to nickel, ruthenium and iron.
Nuclear magnetic resonance spectroscopy (NMR) is a form of spectroscopy that yields detailed mechanistic information about chemical structures, reactions, and processes. Photochemistry has widespread use across many industries and holds excellent utility for additive manufacturing (AM) processes. Here, we use photoNMR to investigate three photochemical processes spanning AM relevant timescales. We first investigate the photodecomposition of a photobase generator on the slow timescale, then the photoactivation of a ruthenium catalyst on the intermediate timescale, and finally the radical polymerization of an acrylate system on the fast timescale. In doing so, we gain fundamental insights to mission relevant photochemistries and develop a new spectroscopic capability at SNL.
Hydrogen utilization at Plug Power sites ranges between 70-93% with the remainder vented and lost to the atmosphere. The goal of this project was to improve hydrogen utilization at Plug Power fulfillment centers via the patented Heisenberg vortex tube (HVT). The HVT combines conventional counterflow vortex tubes with para-orthohydrogen conversion catalyst to allow the cooling of hydrogen flows with no moving parts or external energy inputs. In year 1 of this project the HVT was evaluated to improve hydrogen utilization via the following concepts: 1) increasing liquid hydrogen pump volumetric efficiency by 20% through vapor separation and subcooling of the liquid, 2) reducing liquid hydrogen storage tank boil-off losses by 20% through thermal vapor shielding (TVS), and 3) increase isentropic efficiency of supercritical hydrogen expansion at 40-50 K, from 31% to over 40%. The TVS concept was selected as the most favorable application for further development. While the conceptual analysis was underway, the cryocatalysis hydrogen experiment facility (CHEF) was retrofitted with a new cryocooler, higher pressure condenser tanks, and in-situ fiber-optic Raman probes for ortho-parahydrogen composition analysis at the inlets and outlets of the HVT. To our knowledge this is the first in-situ implementation of cryogenic Raman probes for ortho-parahydrogen analysis. Subsequent testing of catalyzed and non-catalyzed HVT identified a low flow rate, high-conversion efficacy regime well suited for TVS development. Computational fluid dynamics (CFD), Reduced order modeling (ROM), and quantum Monte Carlo atomistic simulations were applied to optimize the design of the HVT implemented for TVS. The simulations and analysis identified a ruthenium-based catalyst as the most optimal for high conversion with little pressure losses and was matched to experimental measurements. These results indicated the design could achieve the 20% boil-off reduction target. An HVT field-trial was designed and constructed by Plug Power and implemented at a customer site. However, budget limitations reduced the amount of catalyst that could be applied to the HVT. With the reduced amount of catalyst, CFD analysis estimated about 3% reduction in boil-off. A similar amount of boil-off reduction was observed during preliminary measurements during tank commissioning. However, the results have a large margin for error and were operated at relatively low tank temperatures when the HVT has the lowest potential for improvement. This project demonstrated the use of para-orthohydrogen catalysis for reducing liquid hydrogen tank boil-off losses. The field trial system is anticipated to provide long-term experimental measurements on tank operational performance that will allow Plug Power to instrument additional tanks in the future. Recommendations for future work include the development of higher activity, lower cost para-orthohydrogen conversion catalyst for use in the HVT. Tank process optimizations could maximize the efficacy of the HVT and further improve hydrogen utilization.