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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

University Partnership Program for Scintillator Materials Research

The Scintillation Detection Development (SDD) group of the Particle Physics Division (PPD) at Fermi National Accelerator Laboratory (Fermilab) conducts research and development work in the field of materials that exhibit scintillation properties for use in particle detection and identification in nuclear and high energy physics experiments and applications. SDD has established a University Partnership Program for Scintillator Materials Research (Program), to facilitate collaboration with faculty and students from local universities. The collaboration between the SDD group and Dominican University will address the development of new plastic scintillating materials in two ways: 3.1. Synthesis of new organic fluorescent compounds to test with plastics commonly used in scintillation applications 3.2. Preparation and testing of commercially available plastics known for their resilience to radiation and rarely used in scintillation applications

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

Identification of the Tyrosine- and Phenylalanine-Derived Soluble Metabolomes of Sorghum

The synthesis of small organic molecules, known as specialized or secondary metabolites, is one mechanism by which plants resist and tolerate biotic and abiotic stress. Many specialized metabolites are derived from the aromatic amino acids phenylalanine (Phe) and tyrosine (Tyr). In addition, the improved characterization of compounds derived from these amino acids could inform strategies for developing crops with greater resilience and improved traits for the biorefinery. Sorghum and other grasses possess phenylalanine ammonia-lyase (PAL) enzymes that generate cinnamic acid from Phe and bifunctional phenylalanine/tyrosine ammonia-lyase (PTAL) enzymes that generate cinnamic acid and p -coumaric acid from Phe and Tyr, respectively. Cinnamic acid can, in turn, be converted into p -coumaric acid by cinnamate 4-hydroxylase. Thus, Phe and Tyr are both precursors of common downstream products. Not all derivatives of Phe and Tyr are shared, however, and each can act as a precursor for unique metabolites. In this study, 13 C isotopic-labeled precursors and the recently developed Precursor of Origin Determination in Untargeted Metabolomics (PODIUM) mass spectrometry (MS) analytical pipeline were used to identify over 600 MS features derived from Phe and Tyr in sorghum. These features comprised 20% of the MS signal collected by reverse-phase chromatography and detected through negative-ionization. Ninety percent of the labeled mass features were derived from both Phe and Tyr, although the proportional contribution of each precursor varied. In addition, the relative incorporation of Phe and Tyr varied between metabolites and tissues, suggesting the existence of multiple pools of p -coumaric acid that are fed by the two amino acids. Furthermore, Phe incorporation was greater for many known hydroxycinnamate esters and flavonoid glycosides. In contrast, mass features derived exclusively from Tyr were the most abundant in every tissue. The Phe- and Tyr-derived metabolite library was also utilized to retrospectively annotate soluble MS features in two brown midrib mutants ( bmr6 and bmr12 ) identifying several MS features that change significantly in each mutant.

09 BIOMASS FUELS↗
DOE OSTI2023

Highly efficient synthesis of zeolite chabazite using cooperative hydration-mismatched inorganic structure-directing agents

Chabazite (CHA type) zeolite is notoriously difficult to synthesize in the absence of organic structure-directing agents owing to long synthesis times and/or impurity formation. The ability to tailor organic-free syntheses of zeolites is additionally challenging due to the lack of molecular level understanding of zeolite nucleation and growth pathways, particularly the role of inorganic cations. In this study, we reveal that zeolite CHA can be synthesized using six different combinations of inorganic cations, including the first reported seed- and organic-free synthesis without the presence of potassium. We show that lithium, when present in small quantities, is an effective accelerant of CHA crystallization; and that ion pairings can markedly reduce synthesis times and temperatures, while expanding the design space of zeolite CHA formation in comparison to conventional methods utilizing potassium as the sole structure-directing agent. Herein, we posit the effects of cation pairings on zeolite CHA crystallization are related to their hydrated ionic radii. We also emphasize the broader implications for considering the solvated structure and cooperative role of inorganic cations in zeolite synthesis within the context of the reported findings for chabazite.

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

Solvent–free Synthesis of Multi–Module Pore–Space–Partitioned Metal–Organic Frameworks for Gas Separation

Multi-module design of framework materials with multiple distinct building blocks has attracted much attention because such materials are more amenable to compositional and geometrical tuning and thus offer more opportunities for property optimization. Few examples are known that use environmentally friendly and cost-effective solvent-free method to synthesize such materials. Here, we report the use of solvent-free method (also modulator-free) to synthesize a series of multi-module MOFs with high stability and separation property for C 2 H 2 /CO 2 . The synthesis only requires simple mixing of reactants and short reaction time (2 h). Highly porous and stable materials can be made without any post-synthetic activation. Here, the success of solvent-free synthesis of multi-module MOFs reflects the synergy between different modules, resulting in stable pore-partitioned materials, despite the fact that other competitive crystallization pathways with simpler framework compositions also exist.

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

Squeezing the box: isoreticular contraction of pyrene-based linker in a Zr-based metal–organic framework for Xe/Kr separation

Isoreticular synthesis is a powerful tool to enhance specific attributes of a metal–organic framework (MOF). While the isoreticular expansion of MOF structure are prevalent in the literature, the compression of a topology holds great promise for separations due to the contracted pore apertures and/or cavities. Herein, we report the synthesis, characterization and Xe/Kr separation capability of a new Zr-based MOF, NU-1106, connected by the tetratopic linker 1,3,6,8-pyrene tetracarboxylate, which exhibits a compressed ftw topology compared to the extended ones reported previously. NU-1106 showed selective uptake of Xenon over Krypton, providing the potential for use for separations.

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

Solvent‐free Synthesis of Multi‐Module Pore‐Space‐Partitioned Metal‐Organic Frameworks for Gas Separation

Abstract Multi‐module design of framework materials with multiple distinct building blocks has attracted much attention because such materials are more amenable to compositional and geometrical tuning and thus offer more opportunities for property optimization. Few examples are known that use environmentally friendly and cost‐effective solvent‐free method to synthesize such materials. Here, we report the use of solvent‐free method (also modulator‐free) to synthesize a series of multi‐module MOFs with high stability and separation property for C 2 H 2 /CO 2 . The synthesis only requires simple mixing of reactants and short reaction time (2 h). Highly porous and stable materials can be made without any post‐synthetic activation. The success of solvent‐free synthesis of multi‐module MOFs reflects the synergy between different modules, resulting in stable pore‐partitioned materials, despite the fact that other competitive crystallization pathways with simpler framework compositions also exist.

Xiao, Yuchen↗
DOE OSTI2021

Buffered Coordination Modulation as a Means of Controlling Crystal Morphology and Molecular Diffusion in an Anisotropic Metal-Organic Framework

We know significant advances have been made in the synthesis of chemically selective environments within metal-organic frameworks, yet materials development and industrial implementation have been hindered by the inability to predictively control crystallite size and shape. One common strategy to control crystal growth is the inclusion of coordination modulators, which are molecular species designed to compete with the linker for metal coordination during synthesis. However, these modulators can simultaneously alter the pH of the reaction solution, an effect that can also significantly influence crystal morphology. Herein, noncoordinating buffers are used to independently control reaction pH during metal-organic framework synthesis, enabling direct interrogation of the role of the coordinating species on crystal growth. We demonstrate the efficacy of this strategy in the synthesis of low-dispersity single-crystals of the framework Co 2 (dobdc) (dobdc 4- = 2,5-dioxido-1,4-benzenedicarboxylate) in a pH 7-buffered solution using cobalt(II) acetate as the metal source. Density functional theory calculations reveal that acetate competitively binds to Co during crystallization, and by using a series of cobalt(II) salts with carboxylate anions of varying coordination strength, it is possible to control crystal growth along the c -direction. Finally, we use zero length column chromatography to show that crystal morphology has a direct impact on guest diffusional path length for the industrially important hydrocarbon m -xylene. Together, these results provide molecular-level insight into the use of modulators in governing crystallite morphology and a powerful strategy for the control of molecular diffusion rates within metal-organic frameworks.

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

Luminescent and magnetic [TbEu] 2D metal–organic frameworks

Here, we present the synthesis, through a simple, microwave-assisted method, of lanthanoid-based 2D metal–organic frameworks (MOFs) of general formula [Ln x Ln' 1–x (MeCOO)(PhCOO) 2 ], including homonuclear compounds (x = 1), Ln$=$Eu, Tb, and heterometallic compounds, [TbEu]. The crystalline material is formed by neutral nanosheets held together by van der Waals interactions, which can be easily exfoliated by sonication. Photoluminescent emission in the visible range was observed for all of the synthesized 2D MOF compounds via excitation of the ligand, showing benzoates are efficient antenna ligands. Efficient energy transfer from Tb → Eu was observed in the heterometallic [TbEu] compounds, which could potentially perform as luminescent thermometers. Inks containing nanosheets of 2D MOFs exfoliated in solution were prepared, and luminescent prints of Tb and Eu 2D MOFs on paper were made to show the possible application for anticounterfeiting. Frequency-dependent ac susceptibility results show the occurrence of slow magnetic relaxation in [TbEu] compounds through direct relaxation mechanisms, affected by bottleneck effect. A slowing down of the relaxation time is observed as the Eu/Tb ratio increases.

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

Templated synthesis enhances the cobalt adsorption capacity of a porous organic polymer

Divalent transition metals such as Co(II) are important targets for removal from water sources, due to their potential toxicity as well as their high value. In this study, we found that a series of porous organic polymers based on amide-linked tetraphenylmethane units are effective Co(II) ion adsorbents in aqueous solution. To increase the density of Co(II) binding sites, we then developed a templated synthesis in which the branched, rigid monomers are pre-assembled around Co(II) ions prior to polymerization. Furthermore, after polymer formation, the Co(II) template ions are removed to yield a material rich in Co(II) binding sites. Ion adsorption isotherms show that the Co(II)-templated material has an ion adsorption capacity significantly greater than those of the non-templated materials, highlighting the utility of a templated synthetic route. SEM and TEM images show the morphology of the templated polymer to be dramatically different from the non-templated polymers and to be similar in size and shape to the Co(II)–monomer precursors, emphasizing the role of the template ions in directing the formation of the resulting polymer. This guest-templated approach requires no functionalization of the generic monomer and represents a promising synthetic route to high-capacity ion adsorbents for water purification and aqueous separations.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Surface-Modified Pd/CeO 2 Single-Atom Catalyst Shows Increased Activity for Suzuki Cross-Coupling

Single-atom catalysts (SACs) comprise catalytically active atoms dispersed on supports; they combine the high activity and site uniformity of homogeneous catalysts with the ease of separability of heterogeneous catalysts. However, SACs lack fine control over the active site, provided by ligands in homogeneous catalysts. In this work, we demonstrate that modification of the support with an organic monolayer is a viable approach to improving the catalytic performance. Here, the addition of catechol-type monolayers to a Pd/CeO 2 SAC increases its catalytic activity for Suzuki cross-coupling, a central reaction in the synthesis of fine chemicals and pharmaceuticals. Kinetic trials reveal that the coating reduces the activation energy from 49 ± 9 to 22 ± 5 kJ/mol and produces a 4-fold rate enhancement at 25 °C, an effect we attribute to π-π interactions between the reactant and the catechol coating. Further development of this approach could vastly increase the utility of SACs in organic synthesis.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

2D Multivariate‐Metal‐Organic Frameworks (2D‐M 2 OF) for High Yield Ammonia Synthesis from Nitrate

Ammonia synthesis from nitrate offers a promising approach for both nitrate removal and nitrogen recycling. In this study, a series of 2D multivariate-metal-organic frameworks (M 2 OFs) is synthesized, incorporating transition metals such as Co, Ni, Mn, and Ag to enhance these processes. These M 2 OFs exhibit remarkable ammonia production performance, with the highest performance achieved using the quaternary structure exceeding a current density of 1 A cm −2 at −0.8 V vs RHE, with an ammonia Faradic efficiency (F.E.) of ≈90%, and a yield rate of 68 mg h −1 cm −2 . Our findings reveal that the synergy among different metal centers in M 2 OFs provides a new efficient reaction pathway for nitrate reduction via surface hydrogen co-adsorption, a mechanism not attainable with single-metal MOFs.

2D-M2OF↗
DOE OSTI2020

A Three‐Dimensional Porous Organic Semiconductor Based on Fully sp 2 ‐Hybridized Graphitic Polymer

Abstract Dimensionality plays an important role in the charge transport properties of organic semiconductors. Although three‐dimensional semiconductors, such as Si, are common in inorganic materials, imparting electrical conductivity to covalent three‐dimensional organic polymers is challenging. Now, the synthesis of a three‐dimensional π‐conjugated porous organic polymer (3D p‐POP) using catalyst‐free Diels–Alder cycloaddition polymerization followed by acid‐promoted aromatization is presented. With a surface area of 801 m 2 g −1 , full conjugation throughout the carbon backbone, and an electrical conductivity of 6(2)×10 −4 S cm −1 upon treatment with I 2 vapor, the 3D p‐POP is the first member of a new class of permanently porous 3D organic semiconductors.

Byun, Yearin↗
DOE OSTI2024

Tuning Surface, Phase, and Magnetization of Superparamagnetic Magnetite by Ionic Liquids: Single-Step Microwave-Assisted Synthesis

Achieving colloidal and chemical stability in ferrofluids by surface modification requires multiple steps, including purification, ex situ modification steps, and operation at high temperatures. In this study, a single-step microwave-assisted methodology is developed for iron oxide nanoparticle (IONP) synthesis utilizing a series of imidazolium-based ionic liquids (ILs) with chloride, bis(trifluoromethylsulfonyl)imide, and pyrrolide anions as the reaction media, thus eliminating the use of volatile organics while enabling rapid synthesis at 80 °C as well as in situ surface functionalization. The characterized surface functionality, hydrodynamic particle size, magnetization, and colloidal stability of the IONPs demonstrate a strong dependence on the IL structure, ion coordination strength, reactivity, and hydrophilicity. The IONPs present primarily a magnetite (Fe 3 O 4 ) phase with superparamagnetism with the highest saturation magnetization at 81 and 73 emu/g at 10 and 300 K, respectively. Depending on the IL coating, magnetization and exchange anisotropy decrease by 20 and 2–3 emu/g (at 35 wt % IL), respectively, but still represent the highest magnetization achieved for coated IONPs by a coprecipitation method. Further, the surface-functionalized superparamagnetic magnetite nanoparticles show good dispersibility and colloidal stability in water and dimethyl sulfoxide at 0.1 mg/mL concentration over the examined 3 month period. This study reports on the intermolecular and chemical interactions between the particle surface and the ILs under synthetic conditions as they relate to the magnetic and thermal properties of the resulting IONPs that are well suited for a variety of applications, including separation and catalysis.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Energetic Insights into the Role of Quaternary Ammonium Cations in Zeolite Synthesis

The thermodynamics of partitioning of an organic structure-directing agent (OSDA) between water and an organic solvent such as chloroform or trichloroethane serve as a proxy for energetic interactions during zeolite synthesis. Using several newly synthesized OSDAs, we have extended our earlier calorimetric and partitioning studies of the thermodynamics of transfer to separate effects of charge (C/N + ratio) and structure in a series of structurally related OSDAs. The Gibbs free energies of transfer are close to zero, resulting from a balance of strongly exothermic and relatively similar enthalpies and strongly negative and relatively similar entropies of transfer. There is no obvious correlation between the thermodynamics of transfer and the efficacy of a given OSDA in the zeolite synthesis. Finally, one must conclude that with bulk energetics of transfer being similar in most cases studied, the critical factors in OSDA function in zeolite synthesis are kinetically rather than thermodynamically controlled and arise from differences in activation energies related to details of OSDA structure and interactions during nucleation of possible zeolite precursors.

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

Using genetic algorithms to systematically improve the synthesis conditions of Al-PMOF

The synthesis of metal-organic frameworks (MOFs) is often complex and the desired structure is not always obtained. In this work, we report a methodology that uses a joint machine learning and experimental approach to optimize the synthesis conditions of Al-PMOF (Al 2 (OH) 2 TCPP) [H 2 TCPP = meso-tetra(4-carboxyphenyl)porphine], a promising material for carbon capture applications. Al-PMOF was previously synthesized using a hydrothermal reaction, which gave a low throughput yield due to its relatively long reaction time (16 hours). Here, we use a genetic algorithm to carry out a systematic search for the optimal synthesis conditions and a microwave-based high-throughput robotic platform for the syntheses. We show that, in just two generations, we could obtain excellent crystallinity and yield close to 80% in a much shorter reaction time (50 minutes). Moreover, by analyzing the failed and partially successful experiments, we could identify the most important experimental variables that determine the crystallinity and yield.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Hybrid magnetic nanoparticles as efficient nanoheaters in biomedical applications

Heating at the nanoscale is the basis of several biomedical applications, including magnetic hyperthermia therapies and heat-triggered drug delivery. The combination of multiple inorganic materials in hybrid magnetic nanoparticles provides versatile platforms to achieve an efficient heat delivery upon different external stimuli or to get an optical feedback during the process. However, the successful design and application of these nanomaterials usually require intricate synthesis routes and their magnetic response is still not fully understood. In this review we give an overview of the novel systems reported in the last few years, which have been mostly obtained by organic phase-based synthesis and epitaxial growth processes. Since the heating efficiency of hybrid magnetic nanoparticles often relies on the exchange-interaction between their components, we discuss various interface-phenomena that are responsible for their magnetic properties. Finally, followed by a brief comment on future directions in the field, we outline recent advances on multifunctional nanoparticles that can boost the heating power with light and combine heating and temperature sensing in a single nanomaterial.

36 MATERIALS SCIENCE↗