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

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At least 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

A Molecular Compound for Highly Selective Purification of Ethylene

Purification of C 2 H 4 from an C 2 H 4 /C 2 H 6 mixture is one of the most challenging separation processes, which is achieved mainly through energy-intensive, cryogenic distillation in industry. Sustainable, non-distillation methods are highly desired as alternatives. We discovered that the fluorinated bis(pyrazolyl)borate ligand supported copper(I) complex {[(CF 3 ) 2 Bp]Cu} 3 has features very desirable in an olefin–paraffin separation material. It binds ethylene exclusively over ethane generating [(CF 3 ) 2 Bp]Cu(C 2 H 4 ). This molecular compound exhibits extremely high and record ideal adsorbed solution theory (IAST) C 2 H 4 /C 2 H 6 gas separation selectivity, affording high purity (>99.5 %) ethylene that can be readily desorbed from separation columns. In-situ PXRD provides a “live” picture of the reversible conversion between [(CF 3 ) 2 Bp]Cu(C 2 H 4 ) and the ethylene-free sorbent in the solid-state, driven by the presence or removal of C 2 H 4 . As a result, molecular structures of trinuclear {[(CF 3 ) 2 Bp]Cu} 3 and mononuclear [(CF 3 ) 2 Bp]Cu(C 2 H 4 ) are also presented.

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

Predicting the Solubility of Inorganic Ion Pairs in Water

Polyoxometalates (POMs), ranging in size from 1 to 10’s of nanometers, resemble building blocks of inorganic materials. Elucidating their complex solubility behavior with alkali-counterions can inform natural and synthetic aqueous processes. Here in the study of POMs ([Nb 24 O 72 H 9 ] 15- , Nb 24 ) we discovered an unusual solubility trend (termed anomalous solubility) of alkali-POMs, in which Nb 24 is most soluble with the smallest (Li + ) and largest (Rb/Cs + ) alkalis, and least soluble with Na/K + . Via computation, we define a descriptor (σ-profile) and use an artificial neural network (ANN) to predict all three described alkali-anion solubility trends: amphoteric, normal (Li + >Na + >K + >Rb + >Cs + ), and anomalous (Cs + >Rb + >K + >Na + >Li + ). Testing predicted amphoteric solubility affirmed the accuracy of the descriptor, provided solution-phase snapshots of alkali–POM interactions, yielded a new POM formulated [Ti 6 Nb 14 O 54 ] 14- , and provides guidelines to exploit alkali–POM interactions for new POMs discovery.

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

Programmable 3D Hexagonal Geometry of DNA Tensegrity Triangles

Non-canonical interactions in DNA remain under-explored in DNA nanotechnology. Recently, many structures with non-canonical motifs have been discovered, notably a hexagonal arrangement of typically rhombohedral DNA tensegrity triangles that forms through non-canonical sticky end interactions. Here, in this study, we find a series of mechanisms to program a hexagonal arrangement using: the sticky end sequence; triangle edge torsional stress; and crystallization condition. We showcase cross-talking between Watson–Crick and non-canonical sticky ends in which the ratio between the two dictates segregation by crystal forms or combination into composite crystals. Finally, we develop a method for reconfiguring the long-range geometry of formed crystals from rhombohedral to hexagonal and vice versa. These data demonstrate fine control over non-canonical motifs and their topological self-assembly. This will vastly increase the programmability, functionality, and versatility of rationally designed DNA constructs.

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

Assembling Phenothiazine into a Porous Coordination Cage to Improve Its Photocatalytic Efficiency for Organic Transformations

Abstract Photo‐catalysis by small‐molecules is often limited by catalyst degradation and low electron‐transfer efficiency. Herein we report a stable N‐phenyl‐phenothiazine (PTH)‐derived porous coordination cage (PCC) as a highly efficient photocatalyst. By the incorporation of the photocatalytic PTH moiety into a PCC, aggregation‐induced quenching (AIQ) was shown to be reduced. An improvement in catalyst stability was discovered, ascribed to the synergistic effects of the PTH moieties. The catalyst, operating through a photolytic single‐electron transfer, was utilized for photo‐catalyzed dehalogenation and borylation. Evaluation of the catalytic mechanism in the borylation reaction showed that the improved performance results from the more efficient formation of the electron donor‐acceptor (EDA) complex with the cage. This discovery provides a potential strategy to improve the photophysical properties and stabilities of small‐molecule organic photocatalysts via supramolecular chemistry.

Chemistry↗
DOE OSTI2023

Single‐Crystal to Single‐Crystal Transformations: Stepwise CO 2 Insertions into Bridging Hydrides of [(NHC)CuH] 2 Complexes

Abstract Mechanistic studies of substrate insertion into dimeric [(NHC)CuH] 2 (NHC=N‐heterocyclic carbene) complexes with two bridging hydrides have been shown to require dimer dissociation to generate transient, highly reactive (NHC)Cu−H monomers in solution. Using single‐crystal to single‐crystal (SC‐SC) transformations, we discovered a new pathway of stepwise insertion of CO 2 into [(NHC)CuH] 2 without complete dissociation of the dimer. The first CO 2 insertion into dimeric [(IPr*OMe)CuH] 2 (IPr*OMe=N,N′‐bis(2,6‐bis(diphenylmethyl)‐4‐methoxy‐phenyl)imidazole‐2‐ylidene) produced a dicopper formate hydride [(IPr*OMe)Cu] 2 (μ‐1,3‐O 2 CH)(μ‐H). A second CO 2 insertion produced a dicopper bis(formate), [(IPr*OMe)Cu] 2 (μ‐1,3‐O 2 CH)(μ‐1,1‐O 2 CH), containing two different bonding modes of the bridging formate. These dicopper formate complexes are inaccessible from solution reactions since the dicopper core cleanly ruptures to monomeric complexes when dissolved in a solvent.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Rational Design and Reticulation of Infinite qbe Rod Secondary Building Units into Metal–Organic Frameworks through a Global Desymmetrization Approach for Inverse C 3 H 8 /C 3 H 6 Separation

Abstract The development of reticular chemistry has enabled the construction of a large array of metal–organic frameworks (MOFs) with diverse net topologies and functions. However, dominating this class of materials are those built from discrete/finite secondary building units (SBUs), yet the designed synthesis of frameworks involving infinite rod‐shaped SBUs remain underdeveloped. Here, by virtue of a global linker desymmetrization approach, we successfully targeted a novel Cu‐MOF (Cu‐ASY) incorporating infinite Cu‐carboxylate rod SBUs with its structure determined by micro electron diffraction (MicroED) crystallography. Interestingly, the rod SBU can be simplified as a unique cylindric sphere packingqbetubule made of [4 3 .6 2 ] tiles, which further connect the tritopic linkers to give a newly discovered 3,5‐connectedgfcnet. Cu‐ASY is a permanent ultramicroporous material featuring 1D channels with highly inert surfaces and shows a preferential adsorption of propane (C 3 H 8 ) over propene (C 3 H 6 ). The efficiency of C 3 H 8 selective Cu‐ASY is validated by multicycle breakthrough experiments, giving C 3 H 6 productivity of 2.2 L/kg. Density functional theory (DFT) calculations reveal that C 3 H 8 molecules form multiple C−H⋅⋅⋅π and atypical C−H⋅⋅⋅ H−C van der Waals interactions with the inner nonpolar surfaces. This work therefore highlights the linker desymmetrization as an encouraging and intriguing strategy for achieving unique MOF structures and properties.

Chemistry↗
DOE OSTI2024

3D Lead-Organoselenide-Halide Perovskites and their Mixed-Chalcogenide and Mixed-Halide Alloys

Here, we incorporate Se into the 3D halide perovskite framework using the zwitterionic ligand: SeCYS ( + NH 3 (CH 2 ) 2 Se - ), which occupies both the X - and A + sites in the prototypical ABX 3 perovskite. The new organoselenide-halide perovskites: (SeCYS)PbX 2 (X=Cl, Br) expand upon the recently discovered organosulfide-halide perovskites. Single-crystal X-ray diffraction and pair distribution function analysis reveal the average structures of the organoselenide-halide perovskites, whereas the local lead coordination environments and their distributions were probed through solid-state 77 Se and 207 Pb NMR, complemented by theoretical simulations. Density functional theory calculations illustrate that the band structures of (SeCYS)PbX 2 largely resemble those of their S analogs, with similar band dispersion patterns, yet with a considerable band gap decrease. Optical absorbance measurements indeed show band gaps of 2.07 and 1.86 eV for (SeCYS)PbX 2 with X=Cl and Br, respectively. We further demonstrate routes to alloying the halides (Cl, Br) and chalcogenides (S, Se) continuously tuning the band gap from 1.86 to 2.31 eV–straddling the ideal range for tandem solar cells or visible-light photocatalysis. The comprehensive description of the average and local structures, and how they can fine-tune the band gap and potential trap states, respectively, establishes the foundation for understanding this new perovskite family, which combines solid-state and organo-main-group chemistry.

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

Unlocking Mesoscopic Disorder in Graphitic Carbon with Spectroelectrochemistry

Intrinsic structural and oxidic defects activate graphitic carbon electrodes towards electrochemical reactions underpinning energy conversion and storage technologies. Yet, these defects can also disrupt the long-range and periodic arrangement of carbon atoms, thus, the characterization of graphitic carbon electrodes necessitates in-situ atomistic differentiation of graphitic regions from mesoscopic bulk disorder. Here, we leverage the combined techniques of in-situ attenuated total reflectance infrared spectroscopy and first-principles calculations to reveal that graphitic carbon electrodes exhibit electric-field dependent infrared activity that is sensitive to the bulk mesoscopic intrinsic disorder. With this platform, we identify graphitic regions from amorphous domains by discovering that they demonstrate opposing electric-field-dependent infrared activity under electrochemical conditions. Our work provides a roadmap for identifying mesoscopic disorder in bulk carbon materials under potential bias.

Disordered graphitic carbon electrodes↗
DOE OSTI2025

Ternary Potassium‐Bismuth‐Telluride Intermetallic Support Promotes Electrochemical Stability in Potassium Metal Anodes

We employed accumulative roll bonding to fabricate self‐standing metallurgical composite of in situ formed alkaline potassium‐bismuth‐telluride intermetallic K 2 (Bi 2/6 Te 3/6 Vac 1/6 ) embedded in potassium metal. This newly discovered thermodynamically stable potassiophilic crystal, termed “KBT”, is fcc antifluorite with K 2 Te archetype. Symmetric cells achieve 880 h of cycling at 0.5 mA cm −2 and 0.5 mAh cm −2 . Potassium metal battery (KMB) with Prussian blue (PB) cathode in carbonate electrolyte retains 80% capacity after 200 cycles at 1C. In ether‐based electrolyte with organic cathode, it achieves 80% retention after 900 cycles at 2C. Combined synchrotron X‐ray nano‐tomography, cryogenic‐focused ion beam microscopy (Cryo‐FIB) and sputter‐down X‐ray photoelectron spectroscopy (XPS) demonstrate uniform electrodeposits, versus baseline of potassium filaments intermixed with pores and coarse SEI. Binary K 3 Bi‐K and K 2 Te‐K intermetallic supports also provide improved electrochemical performance, albeit to lesser extent. Multiscale simulation provides insight into role of support structure in adatom energetics, film nucleation, early‐stage SEI morphology and interfacial stability.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Comparative Study of Solvatomorphs of Stryker's Reagent Using MicroED and Quantum Mechanics

Abstract The atomic position of hydrogen atoms in metal hydrides has been a long‐standing structural question in inorganic chemistry given that hydride delivery is integral to diverse chemical reactions. Microcrystal electron diffraction (microED), with it's increased sensitivity toward hydrogen atoms relative to X‐ray diffraction, offers a potential path to addressing this challenge. Herein, the first microED study of Stryker's reagent is reported, resulting in the structure of a new benzene solvate. Improved accuracy for hydrogen atom positions was obtained via a quantum crystallography (QCr) approach, Hirshfeld atom refinement (HAR). Structural and topological analysis supports edge bridging hydrides in the microED structure of a THF solvate form, consistent with previous diffraction studies. Interestingly, analysis of a new benzene solvate, discovered in this study, is consistent with mixed edge‐ and face‐bridging hydrides.

Jha, Kunal K. [Division of Chemistry &amp, Chemica↗
DOE OSTI2022

Decomposition of Irganox 1010 in plastic bonded explosives

Abstract Degradation pathways of Irganox 1010 in aged plastic bonded explosive (PBX) 9501 were investigated using ultrahigh performance liquid chromatography coupled to quadrupole time of flight mass spectrometry (UHPLC‐QTOF). Using a targeted approach, a total of 44 Irganox 1010 decomposition products were discovered. These decomposition products were formed through hydrolysis, scission, and/or oxidation of Irganox 1010. The hydrolytic decomposition of Irganox is a straightforward process resulting in the cleavage of the ester group(s) while oxidation and scission are more complicated and can happen at multiple locations on the Irganox 1010 molecule. Moreover, due to the symmetric nature of Irganox 1010, multiple decomposition reactions can occur. Indeed some decomposition products exhibited hydrolysis, oxidation, and scission. In order to probe any trends in the aged PBX 9501 samples, principal component analysis (PCA) was implemented. The greatest chemical differences between the aged PBX samples was hydrolysis of the ester functional groups on Irganox 1010. Despite the negative connotations of hydrolysis, the Irganox 1010 decomposition products are still able to function as a radical scavenger in PBX 9501 as intended.

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

Elucidating the Role of Dimensionality on the Electronic Structure of the Van der Waals Antiferromagnet NiPS 3

Abstract The sustained interest in investigating magnetism in the 2D limit of insulating antiferromagnets is driven by the possibilities of discovering, or engineering, novel magnetic phases through layer stacking. However, due to the difficulty of directly measuring magnetic interactions in 2D antiferromagnets, it is not yet understood how intra layer magnetic interactions in insulating , strongly correlated, materials can be modified through layer proximity. Herein, the impact of reduced dimensionality in the model van der Waals antiferromagnet NiPS 3 is explored by measuring electronic excitations in exfoliated samples using Resonant Inelastic X‐ray Scattering (RIXS). The resulting spectra shows systematic broadening of NiS 6 multiplet excitations with decreasing layer count from bulk down to three atomic layers (3L). It is shown that these trends originate from a decrease in transition metal‐ligand and ligand–ligand hopping integrals, and by charge‐transfer energy evolving from Δ = 0.83 eV in the bulk to 0.37 eV in 3L NiPS 3 . Relevant intralayer magnetic exchange integrals computed from the electronic parameters exhibit a decrease in the average interaction strength with thickness. This study underscores the influence of inter layer electronic interactions on intra layer ones in insulating magnets, indicating that magnetic Hamiltonians in few‐layer insulating magnets can greatly deviate from their bulk counterparts.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Synthesis and Processing by Design of High-Nickel Cathode Materials

The high demand of lightweight, high energy density batteries for energy storage promotes new materials discovery and development. Despite the large number of battery materials being discovered, very few of them have been commercially deployed, mostly bottlenecked by synthesis and processing – namely, making certain phases with the desired structure and properties to meet the multifaceted performance requirements. Alternative to the traditional trial and error, we present here an in situ study aided synthesis- and processing-by-design approach. With specific examples, we illustrate how to use the approach to identify reaction pathways in synthesis and processing of high-Nickel (Ni) cathode materials for next-generation lithium-ion batteries, thereby ensuring precise control of their structure, morphology, and surface properties. Furthermore, perspectives are provided on the wide applicability of the approach to solving critical issues inherent to high-Ni cathodes and the new directions and opportunities in the area.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Dispersion of sulfur creates a valuable new growth medium formulation that enables earlier sulfur oxidation in relation to iron oxidation in Acidithiobacillus ferrooxidans cultures

Abstract Acidithiobacillus ferrooxidans is an acidophilic chemolithoautotroph that is commonly reported to exhibit diauxic population growth behavior where ferrous iron is oxidized before elemental sulfur when both are available, despite the higher energy content of sulfur. We have discovered sulfur dispersion formulations that enables sulfur oxidation before ferrous iron oxidation. The oxidation of dispersed sulfur can lower the culture pH within days below the range where aerobic ferrous iron oxidation can occur. Thus, ferric iron reduction can be observed quickly which had previously been reported over extended incubation periods with untreated sulfur. Therefore, we demonstrate that this substrate utilization pattern is strongly dependent on the cell loading in relation to sulfur concentration, sulfur surface hydrophobicity, and the pH of the culture. Our dispersed sulfur formulation, lig‐sulfur, can be used to support the rapid antibiotic selection of plasmid‐transformed cells, which is not possible in liquid cultures where ferrous iron is the main source of energy for these acidophiles. Furthermore, we find that media containing lig‐sulfur supports higher production of green fluorescent protein compared to media containing ferrous iron. The use of dispersed sulfur is a valuable new tool for the development of engineered A. ferrooxidans strains and it provides a new method to control iron and sulfur oxidation behaviors.

Inaba, Yuta↗
DOE OSTI2024

Metabolic Engineering of Nonmodel Yeast Issatchenkia orientalis SD108 for 5–Aminolevulinic Acid Production

Biological production of 5-aminolevulinic acid (5-ALA) has received growing attention over the years. However, there is the tradeoff between 5-ALA biosynthesis and cell growth because the fermentation broth will become acidic due to the production of 5-ALA. To address this limitation, we engineered an acid-tolerant yeast, Issatchenkia orientalis SD108, for 5-ALA production. We first discovered that the cell growth rate of I. orientalis SD108 was boosted by 5-ALA and its endogenous ALA synthetase (ALAS) showed higher activity than those homologs from other yeasts. The titer of 5-ALA was improved from 28 mg/L to 120-, 150-, and 300 mg/L, by optimizing plasmid design, overexpressing a transporter, and increasing gene copy number, respectively. After redirecting the metabolic flux using the pyruvate decarboxylase (PDC) knockout strain (SD108ΔPDC) and culturing with urea, we increased the titer of 5-ALA to 510 mg/L, a 13-fold enhancement, proving the importance of the newly identified IoALAS with higher activity and the strategic selection of nitrogen sources for knockout strains. This study demonstrates the acid-tolerant I. orientalis SD108ΔPDC has a high potential for 5-ALA production at a large scale in the future.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2026

Engineering of 2‐ketoacid Decarboxylases for Production of Isobutanol and Other Fusel Alcohols in Saccharomyces cerevisiae

Isobutanol is a fusel alcohol that can be produced microbially for use as a biofuel or upgraded into sustainable aviation fuel (SAF). A key enzyme in the isobutanol biosynthetic pathway is 2-ketoacid decarboxylase (KDC), which irreversibly decarboxylates 2-ketoisovalerate (KIV) to yield isobutyraldehyde. However, many previously characterized KDC enzymes also act promiscuously on other 2-ketoacids, (e.g., pyruvate) to produce a related aldehyde (e.g., acetaldehyde). This unwanted side reaction is especially important when isobutanol is produced in Saccharomyces cerevisiae (S. cerevisiae) because it leads to pyruvate being diverted to ethanol. In order to make S. cerevisiae a strict isobutanologen, a KDC enzyme that is specific for KIV must be deployed. In this study, we used a combination of cell-based and in vitro enzyme assays to investigate KDC substrate specificity, characterizing a large set of homologs for KIV, pyruvate, and phenylpyruvate (PPV) activity. A diverse range of substrate specificities was discovered, and some previously uncharacterized KDCs were revealed to have high KIV activity and low pyruvate activity. Multi-site saturation mutagenesis (SSM) of one of these KDCs identified mutants with increased KIV activity, while maintaining low levels of pyruvate activity. In a KIV bioconversion experiment, bioprospected and engineered KDCs allowed similar KIV consumption to when using the previously characterized Lactococcus lactis KdcA, though with some ethanol also produced. The KDCs identified here show promise for production of isobutanol and other alcohols derived from 2-ketoacids, and the dataset of newly characterized KDCs can inform future efforts to understand and engineer substrate specificity in KDCs.

2-ketoacid decarboxylase↗
DOE OSTI2024

Enhancing 2‐Pyrone Synthase Efficiency by High‐Throughput Mass‐Spectrometric Quantification and In Vitro/In Vivo Catalytic Performance Correlation

Abstract Engineering efficient biocatalysts is essential for metabolic engineering to produce valuable bioproducts from renewable resources. However, due to the complexity of cellular metabolic networks, it is challenging to translate success in vitro into high performance in cells. To meet such a challenge, an accurate and efficient quantification method is necessary to screen a large set of mutants from complex cell culture and a careful correlation between the catalysis parameters in vitro and performance in cells is required. In this study, we employed a mass‐spectrometry based high‐throughput quantitative method to screen new mutants of 2‐pyrone synthase (2PS) for triacetic acid lactone (TAL) biosynthesis through directed evolution in E. coli . From the process, we discovered two mutants with the highest improvement (46 fold) in titer and the fastest k cat (44 fold) over the wild type 2PS, respectively, among those reported in the literature. A careful examination of the correlation between intracellular substrate concentration, Michaelis‐Menten parameters and TAL titer for these two mutants reveals that a fast reaction rate under limiting intracellular substrate concentrations is important for in‐cell biocatalysis. Such properties can be tuned by protein engineering and synthetic biology to adopt these engineered proteins for the maximum activities in different intracellular environments.

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

Mechanisms in the Synthesis of S -Alcohols with 1,4-NADH Biomimetic Co-factor N-Benzyl-1,4-dihydronicotinamide using Horse Liver Alcohol Dehydrogenase: A Hybrid Computational Study

The enantioselective reduction of prochiral ketones catalyzed by horse liver alcohol dehydrogenase (HLADH), was investigated via a hybrid computational approach, for molecular reactions involved in chiral synthesis of S-alcohols, when the natural co-factor, 1,4-dihyronicotinamide adenine dinucleotide, 1,4-NADH, was replaced with biomimetic co-factor, N-benzyl-1,4-dihydronicotinamide, 1. We surmised that different hydride and proton transfer mechanisms were involved using co-factor, 1. An alternative mechanism, where the hydride transfer step occurred, via an η 1 -keto-S-η 2 -5,6-1,4-dihydronicotinamide-Zn(II) complex, was previously investigated with a model of the HLADH-Zn(II) catalytic site (J. Organometal. Chem. 2021, 943, 121810). Presently, we studied canonical and alternative mechanisms compared to models of the entire enzyme structure. We disproved the η 2 -Zn(II) complex, and discovered a canonical hydride transfer from biomimetic 1,4-NADH, 1, to the Zn(II) bound prochiral ketone substrate, followed by a new proton relay, consisting of a water chain connecting His51 to Ser48 that accomplished the S-alkoxy anion's protonation to yield the final S-alcohol product. The HLADH catalysis, with biomimetic co-factor, 1, that replaced the ribose group, the 5'-diphosphate groups, and the adenine nucleotide with a N-benzyl group, has provided a new paradigm for the design of other structures of 1,4-NADH biomimetic co-factors, including their economic value in biocatalysis reactions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗