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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 793 records · Page 44
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Assembly of three new POM-based Ag(I) coordination polymers with antibacterial and photocatalytic properties

Three new silver coordination polymers, namely, {Ag_3(bpy)_6[PW_1_2O_4_0]} (1), {Ag_5(H_2biim)_2(Hbiim-NO_2)_2[PW_1_2O_4_0]} (2), {Ag_7(pytz)_4[PW_1_2O_4_0]} (3) (bpy=2,2′-bipyridine, H{sub 2}biim=2,2′-biimidazole, pytz=4-(1H-tetrazol-5-yl)pyridine), have been synthesized under hydrothermal condition. Compound 1 shows a 3D supramolecular framework based on 0D moieties. Compound 2 exhibits an attractive 2D biologic screw axis. Compound 3 displays a 3D structure, which consists of Ag(I)···π interactions, π···π stacking and weak Ag···Ag interactions. It is noteworthy that nitration happens to compound 2 during the hydrothermal condition, which is quite rare. Through contrasting the antibacterial activities of gram negative and gram positive bacteria, we find compounds 1–3 have better antibacterial property in gram negative bacteria than gram positive bacteria. In addition, compounds 1–3 also exhibit efficiency of photocatalytic decomposition of organic dyes. Those compounds may be used as potential multifunctional materials in wastewater treatment, because they not only can kill bacteria but also degrade organic pollutants. - Highlights: • Three new silver coordination polymers have been synthesized under hydrothermal condition. • Due to different coordination modes of rigid N-donor ligands, structures of the title compounds vary from 0D to 3D frameworks. • It is noteworthy that nitration happens to compound 2 during the hydrothermal condition, which is quite rare. • In addition, these compounds exhibit efficiency of photocatalytic decomposition of dyes and antibacterial activities.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Highly regenerable carbon-Fe{sub 3}O{sub 4} core–satellite nanospheres as oxygen reduction electrocatalyst and magnetic adsorbent

We present the synthesis and multifunctional utilization of core-satellite carbon-Fe{sub 3}O{sub 4} nanoparticles to serve as the enabling platform for a range of applications including oxygen reduction reaction (ORR) and magnetic adsorbent. Starting from polydopamine (PDA) nanoparticles and Fe(NO{sub 3}){sub 3}, carbon-Fe{sub 3}O{sub 4} core–satellite nanospheres are synthesized through successive steps of impregnation, ammoniation and carbonization. The synergistic combination of Fe{sub 3}O{sub 4} and N-doped carbon endows the nanocomposite with high electrochemical activity in ORR and mainly four electrons transferred in reaction process. Furthermore, carbon-Fe{sub 3}O{sub 4} nanoparticles used as magnetic adsorbent exhibit the efficient removal of Rhodamine B from an aqueous solution. The recovery and reuse of the adsorbent is demonstrated 5 times without any detectible loss in activity. - Graphical abstract: Starting from polydopamine (PDA) nanoparticles and Fe(NO{sub 3}){sub 3}, carbon-Fe{sub 3}O{sub 4} core–satellite nanospheres are synthesized through successive steps of impregnation, ammoniation and carbonization. The nanocomposites serve as the enabling platform for a range of applications including oxygen reduction reaction (ORR) and magnetic adsorbent. - Highlights: • Carbon-Fe{sub 3}O{sub 4} core–satellite nanospheres are synthesized through successive steps of impregnation, ammoniation and carbonization. • Polydopamine and Fe(NO{sub 3}){sub 3} are precursors for N-doped carbon source and Fe{sub 3}O{sub 4} nanoparticles, respectively. • The nanocomposites exhibit high electrochemical activity in ORR. • The nanocomposites effectively adsorb organic dyes with magnetic recovery and good recycle property.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Facile and low cost oxidative conversion of MoS{sub 2} in α-MoO{sub 3}: Synthesis, characterization and application

This study describes a facile low cost route to synthesize the α-MoO{sub 3} through a conversion of the precursor MoS{sub 2} in oxidant media. The structure and morphology of the α-MoO{sub 3} were studied by high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The results show that α-MoO{sub 3} was obtained with reduced size, high purity, strongly-preferred orientation and structural defects, which ensures versatility and multifunctionality to this sample. For the purpose of applications, α-MoO{sub 3} was successfully employed in inverted organic solar cells devices as a possible alternative to the PEDOT:PSS in the hole transportation layer. - Graphical abstract: Synthesis process based on low cost oxidative conversion of MoS{sub 2} in α-MoO{sub 3} Display Omitted - Highlights: • A facile route to obtain α-MoO{sub 3} by refluxing the MoS{sub 2} precursor in oxidant media. • High purity and strongly-preferred orientation. • Belt-shaped material. • Enhanced conversion efficiency (PCE) when compared with conventional PEDOT:PSS.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Four different dimensional Zn(II) coordination polymers as fluorescent sensor for detecting Hg{sup 2+}, Cr{sub 2}O{sub 7}{sup 2-} in aqueous solution

Highlights: • Four Zn-based coordination polymers were solvethermally synthesized. • Compound 1 and 2 could mutual conversion between different solvent ratios. • Both 1 and 2 exhibit high selectivity for Cr{sub 2}O{sub 7}{sup 2-} and Hg{sup 2+} ions in aqueous solution. • The mechanism of sensing properties were discussed in details. - Abstract: Four Zn(II) coordination polymers (CPs), [Zn(4-pzpt){sub 2}(H{sub 2}O)]{sub n} (1), {[Zn(4-pzpt)_2]·CH_3OH}{sub n} (2), [Zn{sub 2}(4-pzpt){sub 2}(suc)(H{sub 2}O)]{sub n} (3) and [Zn{sub 2}(4-pzpt){sub 2}(ndc)]{sub n} (4) were obtained from 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole (4-Hpzpt), 1,4-Naphthalenedicarboxylic acid (H{sub 2}ndc) and succinic acid (H{sub 2}suc) ligands. Structural analysis reveals that 1 represents a five coordinated 0D structure. 2 possess a network featuring 2D 4{sup 4} grid-like layers structure. 3 displays a network featuring 2D (6{sup 3})-hcb layered structure. 4 shows a rare 3D (4,4)-connected topology with a Schläfli symbol of (4.6{sup 4.}7){sub 2}(6{sup 4.}7{sup 2}). Complexes 1 and 2 can mutual conversion between different solvent ratios. Luminescence properties reveal that 1 and 2 exhibit excellent selectivity for Hg{sup 2+} and Cr{sub 2}O{sub 7}{sup 2-} ions in aqueous solution, in which suggests that 1 and 2 is a promising multifunctional sensing materials. The possible sensing mechanism is also discussed.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

A solid-state extrusion pathway extensible to upcycling aluminum scrap and end-of-life permanent magnets into ductile Al-6061/SmCo 5 structural magnetic composites

Permanent magnets offer strong potential for multifunctional structural components, but their inherent brittleness limits direct integration. Here, SolidStir® Extrusion (SSE) is used to embed SmCo5 powder into AA6061 in the solid state, and the resulting microstructure, interfacial chemistry, mechanical properties, and magnetic response are systematically characterized. SSE fragments the initial SmCo 5 powder into predominantly fine particles dispersed within an ultrafine Al matrix, with a volume fraction of ∼ 4–6 % in this proof-of-concept study. Interfacial reactions form a continuous Al–Co reaction layer, with local atomic-resolution indexing consistent with Al 13 Co 4 , together with Sm–Si-rich reaction products, while the matrix contains Sm–Co–Si-rich precipitates and Mg 2 Si, producing features from nanometers to micrometers. Compared with an Al extrudate, this architecture increases yield strength by ∼ 42 % and tensile strength by ∼ 31 %, while preserving uniform elongation, and it sustains work hardening in compression from 150 to 400 °C. The composite retained hard-magnetic behavior, with axial magnetization of 12.7 A·m 2 kg −1 at 6 T and intrinsic coercivity of 9.6 kOe. These findings demonstrate that SSE can produce Al-based load-bearing magnetic composites while preserving useful SmCo5 functionality.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Nanostructured columnar heterostructures of TiO{sub 2} and Cu{sub 2}O enabled by a thin-film self-assembly approach: Potential for photovoltaics

Graphical abstract: Display Omitted Highlights: ► Material self-assembly in phase-separated oxides is exploited. ► Three-dimensionally nanostructured epitaxial films are grown using sputtering. ► Films are composed of well-ordered oriented nanopillars of n-type TiO{sub 2} and p-type Cu{sub 2}O. ► Observed interfaces at adjacent TiO{sub 2}–Cu{sub 2}O columns are nearly atomically distinct. ► Absorption profile of the composite film captures a wide range of the solar spectrum. -- Abstract: Significant efforts are being devoted to the development of multifunctional thin-film heterostructures and nanostructured material architectures for components with novel applications of superconductivity, multiferroicity, solar photocatalysis and energy conversion. In particular, nanostructured assemblies with well-defined geometrical shapes have emerged as possible high efficiency and economically viable alternatives to planar photovoltaic thin-film architectures. By exploiting phase-separated self-assembly, here we present advances in a vertically oriented two-component system that offers potential for future development of nanostructured thin film solar cells. Through a single-step deposition by magnetron sputtering, we demonstrate growth of an epitaxial, composite film matrix formed as self-assembled, well ordered, phase segregated, and oriented nanopillars of n-type TiO{sub 2} and p-type Cu{sub 2}O. The composite films were structurally characterized to atomic resolution by a variety of analytical tools, and evaluated for preliminary optical properties using absorption measurements. We find nearly atomically distinct TiO{sub 2}–Cu{sub 2}O interfaces (i.e., needed for possible active p–n junctions), and an absorption profile that captures a wide range of the solar spectrum extending from ultraviolet to visible wavelengths. This high-quality materials system could lead to photovoltaic devices that can be optimized for both incident light absorption and carrier collection.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2013

Wide band gap p-type nanocrystalline CuBO{sub 2} as a novel UV photocatalyst

Graphical abstract: - Highlights: • CuBO{sub 2} nanocrystals were synthesized by sol–gel route. • The products have been characterized to confirm the formation of CuBO{sub 2}. • Photocatalytic activity of this material is reported for the first time. - Abstract: Wide band gap copper based delafossite CuBO{sub 2} nanocrystalline powders of different particle sizes were synthesized via sol–gel route. Structural characterization was performed using X-ray diffraction (XRD) and transmission electron microscopy (TEM) which confirmed good crystallinity and proper phase formation of the samples. Compositional analysis was carried out by energy dispersive X-ray studies (EDX), whereas field emission scanning electron microscopy revealed morphological information of the samples. The photocatalytic performance of this delafossite material was studied for the first time with a standard photocatalytic set-up and the photocatalytic efficiency was found to increase with decreasing particle size. The Langmuir–Hinshelwood photocatalytic rate constants increased considerably for the samples synthesized at different pH from 2.75 to 0.5; which eventually varied particle size. The efficient photocatalytic performance, found for the first time here, will make this novel p-type wide band gap semiconductor a truly multifunctional material.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Eu{sup 3+} luminescence enhancement by intercalation of benzenepolycarboxylic guests into Eu{sup 3+}-doped layered gadolinium hydroxide

Graphical abstract: Two benzenepolycarboxylic sensitizers, 1,3,5-benzenetricarboxylic acid (BTA) and 1,2,4,5-benzenetetracarboxylic acid (BA), were intercalated into NO{sub 3}–LGdH:Eu, in which different structures of the compounds resulted in varied arrangement in the gallery. The two organic compounds especially BA markedly enhanced the red luminescence of Eu{sup 3+} due to efficient energy transfer between the organic guests and Eu{sup 3+} centers. - Highlights: • We report the intercalation of benzenepolycarboxylic organic sensitizers into LRH. • We study the intercalation structure and the arrangement of the interlayer guests. • The two organic compounds can markedly enhance the luminescence of Eu{sup 3+}. • There exists efficient energy transfer between organic guests and Eu{sup 3+} centers. • This material opens a route for fabricating new multifunctional luminescent materials. - Abstract: Two benzenepolycarboxylic organic sensitizers, 1,3,5-benzenetricarboxylic acid (BTA) and 1,2,4,5-benzenetetracarboxylic acid (BA), were intercalated into the gallery of NO{sub 3}{sup −} type Eu{sup 3+}-doped layered gadolinium hydroxide (NO{sub 3}–LGdH:Eu). CHN analysis, FTIR, and SEM were employed to characterize the intercalation structures of the as-prepared organic/inorganic hybrids. The area per unit charge (S{sub charge}) was used to explain the intercalation structure and the arrangement of the interlayer guests. Different structures of the two organic compounds resulted in varied arrangement of guests. Photoluminescence studies indicated that both of the two organic compounds especially BA markedly enhanced the red luminescence of Eu{sup 3+} due to efficient energy transfer between the organic guests and Eu{sup 3+} centers.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Photoluminescence and electrical characterization of unfilled tetragonal tungsten bronze Ba{sub 4}La{sub 1−x}Eu{sub x}TiNb{sub 9}O{sub 30}

Graphical abstract: PL spectra of the unfilled TTB structure BLTN: Eu{sup 3+}x samples (x = 0.00, 0.25, 0.50, 0.75, and 1.00) excited by 399 nm. The inset is a schematic diagram of the unfilled TTB structure. - Highlights: • Unfilled TTB structure BLTN: Eu{sup 3+}x ceramics have been synthesized. • Photoluminescenct properties of the BLTN: Eu{sup 3+}x ceramics have been first reported. • Bright red emission excited by NUV light has been observed at room temperature. • Obvious variations of dielectric characteristics have been confirmed. • Relaxor-like ferroelectric phase transitions have been detected. - Abstract: Unfilled tetragonal tungsten bronze (TTB) structure Ba{sub 4}LaTiNb{sub 9}O{sub 30} doped by Eu{sup 3+} (BLTN: Eu{sup 3+}x) with different x have been prepared, and their structural, photoluminescence, dielectric, and ferroelectric properties are carefully investigated in this work. Bright red emission, originating from {sup 5}D{sub 0} → {sup 7}F{sub 1} and {sup 5}D{sub 0} → {sup 7}F{sub 2} transitions of Eu{sup 3+} ions, has been observed by naked eyes at room temperature under near ultraviolet (NUV) light excitation. Optimized emission intensity is obtained when x = 1.00 for present unfilled TTB-type BLTN: Eu{sup 3+}x samples. Furthermore, with increasing x, the dielectric and ferroelectric characteristics of the unfilled TTB-type BLTN: Eu{sup 3+}x samples also display remarkable variation. When x ≥ 0.50 relaxor-like ferroelectric phase transitions are detected above room temperature, it is believed that unfilled TTB-type BLTN: Eu{sup 3+}x = 1.00 involving bright photoluminescence and enhanced ferroelectric properties may act as a potentially multifunctional optical-electro material.

36 MATERIALS SCIENCE↗
DOE OSTI2014

A comparative investigation on structure and multiferroic properties of bismuth ferrite thin films by multielement co-doping

Highlights: • Multielement (Tb, Cr and Mn) co-doped BiFeO{sub 3} films were fabricated by CSD method. • Multielement co-doping induces a structural transition. • It is found effective to stabilize the valence of Fe ions at +3 by the strategy. • The co-doping at A/B-sites gives rise to the superior multiferroic properties. - Abstract: (Tb, Cr and Mn) multielement co-doped BiFeO{sub 3} (BTFCMO) thin films were prepared by the chemical solution deposition method on fluorine doped tin oxide (FTO) substrates. X-ray diffraction, Rietveld refinement and Raman analyses revealed that a phase transition from rhombohedral to triclinic structure occurs in the multielement co-doped BiFeO{sub 3} films. It is found that the doping is conducive to stabilizing the valence of Fe ions and reducing leakage current. In addition, the highly enhanced ferroelectric properties with a huge remanent polarization (2P{sub r}) of 239.6 μC/cm{sup 2} and a low coercive field (2E{sub c}) of 615.6 kV/cm are ascribed to the well film texture, the structure transition and the reduced leakage current by the co-doping. Moreover, the structure transition is the dominant factor resulting in the significant enhancement observed in magnetization (M{sub s} ∼ 10.5 emu/cm{sup 3}), owing to the collapse of the space-modulated spin structure. In this contribution, these results demonstrate that the multielement co-doping is in favor of the enhanced multiferroic properties of the BFO films for possible multifunctional applications.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Biocompatible Bi(OH)3 nanoparticles with reduced photocatalytic activity as possible ultraviolet filter in sunscreens

Highlights: • Facilesynthesis of inorganic Bi(OH){sub 3} nanoparticles. • High biocompatibility in human skin and dog kidney cells in vitro. • Ultraviolet filter capable of reducing the photocatalytic activity of TiO{sub 2} and ZnO. • Preparation of TiO{sub 2}/Bi(OH){sub 3} and classical TiO{sub 2}/ZnO sunscreen formulations. • Significantly improved photoprotection and photostability compared to TiO{sub 2}/ZnO. - Abstract: In this study we investigate readily synthesised Bi(OH){sub 3} nanoparticles as a novel, multifunctional ultraviolet filter for sunscreen. The absorbance of Bi(OH){sub 3} NPs in the ultraviolet region is comparable to that of both ZnO and TiO{sub 2} NPs used in commercial sunscreens. In vitro photoprotection results show that the combination of TiO{sub 2}/Bi(OH){sub 3} is more efficient than TiO{sub 2}/ZnO over the whole UV range, with an increase in sun protection factor of 28%. The emulsions show rheological properties comparable to those of commercial sunscreens. The combination of TiO{sub 2}/Bi(OH){sub 3} led to insignificant damage on pre-painted steel panels after exterior exposure for twelve weeks. We also demonstrate that the addition of Bi(OH){sub 3} NPs reduces the degradation of crystal violet by photocatalytically active TiO{sub 2} or ZnO NPs under ultraviolet exposure. Finally, assessment of the biocompatibility of Bi(OH){sub 3} with HaCaT keratinocytes and Madin-Darby Canine Kidney (MDCK) cells in vitro is described.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2020

Functionalized separator for next-generation batteries

Advancements in battery technology have dramatically increased demand for improvements in separator design, as the separator plays a critical role in ensuring the safety and electrochemical performance of the cells. Current separators, either in commercial usage or under investigation, have yet to meet the high stability and lifespan performance standards necessary to prevent deterioration in the efficiency and reliability of the battery technologies. Recently, considerable effort has been devoted to developing functionalized separators, ranging from designing a variety of new materials and modification methods, and increasingly, to optimizing advanced preparation processes. In order to understand how the mechanisms of separator performance are affected by different properties, we will first summarize recent research progress and then have in-depth discussions regarding the separator's significant contribution to enhancing the safety and performance of the cell. Additionally, we then provide our design strategy for future separators, which not only meets the requirements of different type of batteries, but also aims for multifunctionality. We hope such a perspective could provide new inspiration in the development of separator research for future battery technologies.

25 ENERGY STORAGE↗
DOE OSTI2026

Effect of fiber sizing and glass fiber laminate hybridization on vibration damping and mechanical properties of banana fiber reinforced polypropylene composites

Modern automotive applications demand lightweight, multifunctional materials to reach mileage goals and natural fiber reinforced composites (NFRCs) are one of the classes of materials proposed as a solution. NFRCs exhibit good vibration damping properties and have low density, but are often limited by processing challenges, poor-fiber matrix compatibility and variable performance. Herein, we investigate non-woven wet-lay of comingled banana fiber (BF), recycled glass fiber (rGF), and polypropylene (PP) fibers to in situ sizing and preparation of composite feedstocks for compression molding. BF and rGF hybrids were prepared by stacking rGF layers during compression molding to produce composites with various fiber ratios. The effect of fiber content, in-situ sizing and ratio of BF to rGF on tensile, flexural and vibration damping performance are investigated. Key results are the significant increase in tensile strength by in situ sizing (40 % sized at 60 wt% BF) and in flexural modulus (+58 % sized at 60 wt% BF) and flexural strength (+41 % sized 60 wt% BF) compared to the unsized equivalent. For BF-rGF hybrid composites with40 wt% total fiber content, flexural strength and modulus were improved by 51 % and 231 % respectively for a 1:1 ratio BF:rGF compared to BF reinforced system. Lastly, identifying the cross-over point where damping and stiffness are optimized for a hybrid composite. These findings demonstrate that these composites can be used as alternative to synthetic fiber or mineral filled composites in automotive applications, particularly where weight reduction, vibration damping and stiffness are desired.

Banana fiber↗
DOE OSTI2026

A synergistic approach to improve the cellulose nanofibril dispersion in poly(lactic acid) composites as feedstocks for extrusion-based additive manufacturing

Hybrid fiber-reinforced polymer composites (HFRPs) are multifunctional materials that bear more than one characteristic benefit. In this study, hybrid cellulose fibers, e.g., pulp fiber (PF) and cellulose nanofibril (CNF), were used for reinforcing poly(lactic acid) (PLA). A synergistic approach was applied to disperse CNF. The low-surface-tension solvent (ethanol), together with PF templating, assisted the dispersion of CNF in PLA. The HFRP achieved a higher tensile strength (∼70 MPa, 29% increase from PLA) and modulus (∼7 GPa, 46% increase from PLA), as well as a higher heat deflection temperature (∼60℃, 6℃ increase compared to neat PLA), compared to single-reinforcement FRPs. Additionally, the formulation was demonstrated to be potentially suitable for large-scale additive manufacturing.

Bista, Bivek [University of Maine]↗
DOE OSTI2017

A rationally designed polysulfide-trapping interface on the polymeric separator for high-energy Li–S batteries

A coating layer consisting of a layer of graphene oxide (GO) inserted in between two layers of multi-walled carbon nanotubes (MWCNT) forms a multifunctional polysulfide-trapping triple-interface on the polymeric separator for lithium–sulfur (Li–S) batteries. The top and bottom highly conductive MWCNT interfaces are able to physically inhibit polysulfide diffusion and effectively reutilize the trapped active material during cycling. The inserted ultrathin GO layer with negatively charged carboxyl groups, on the other hand, electrostatically repels the migrating polysulfide anions. The stacked GO sheets also extensively prolong the migration routes of the polysulfides. Additionally, the “buffer zones” interspersed within the triple-interface accommodate the migrating polysulfides. Thus, the sandwiched separators enable Li–S cells with a high-sulfur-loading (10 mg cm -2 ), high areal capacity (10.9 mA h cm -2 ), and stable cycling ability even though the coating layer is ultra-thin (~17 μm) and light-weight (~0.23 mg cm -2 ).

25 ENERGY STORAGE↗
DOE OSTI2024

Support size regulated ruthenium-sulfoacid-nitrogen sites intensify cellulose hydrogenolysis to 1,2-propylene glycol

Rational design of metal-acid-base multifunctional catalysts for upgrading cellulose to 1,2-propylene glycol (1,2-PG) is of great significance for building a sustainable world. However, it is time-consuming and tedious to regulate metal-acid-base sites to balance major reactions to render a high 1,2-PG yield. We herein report support size simultaneously regulated ruthenium-sulfoacid-nitrogen (Ru–SO 3 H–N) sites for cellulose hydrogenolysis to high yield 1,2-PG. Originated from the depolymerization and reassembly of zinc-1,3,5-benzenetricarboxylic acid (ZnBTC) fiber with zeolitic imidazolate framework (ZIF-8) in water, 2-methylimidazole infiltrated nanorod (ZnBTC(mIM)) with a varied aspect ratio was fabricated by varying the feed ratio of ZIF-8/ZnBTC. Upon being pyrolyzed, sulfonated and impregnated with Ru ions, the supported sites were tailored in terms of Ru single-atom/nanocluster ratio, SO 3 H acidity and N basicity. Further, the elaborately fabricated catalyst delivers 32.3% yield of 1,2-PG, corresponding to a high productivity of 67.71 mol h -1 g Ru -1 and a large turnover number of 34193, two and three orders of magnitude higher than those by using other Ru-containing catalytic systems for cellulose hydrogenolysis. The excellent performance can be attributed to optimized electronic and molecular structure of Ru–SO 3 H–N sites that can improve rate-determining cellulose hydrolysis/fructose hydrogenolysis, pivotal glucose isomerization with others to proceed at a matched rate. This study opens a new avenue to facilely tailor the metal-acid-base sites by rational design of size controlled supporting matrix.

1,2-Propylene glycol↗
DOE OSTI2023

3D printable polyvinyltoluene-based plastic scintillators with pulse shape discrimination

A feasibility of preparing bulk photopolymerized plastics scintillators that contain vinyltoluene with multifunctional monomers, pentaerythritol tetraacrylate is shown. This formulation offers a simple and fast way to prepare polyvinyltoluene-based plastics with efficient fast neutron/gamma pulse shape discrimination (PSD) within minutes. 30 wt% of 2,5-diphenyloxazole (PPO) was added in the mixtures of vinyltoluene and pentaerythritol tetraacrylate with different secondary dyes to understand the effect of dyes on the scintillation. Prepared resins were photopolymerized under different conditions, and the scintillation performance was compared to a commercially available standard, EJ-276. Additional functionality for thermal neutron sensitivity was introduced by the incorporation of 6 Li and 6 B nuclei. With optimized conditions, prepared plastics showed light output up to 90% relative to the same size of EJ-276. Here, the best plastic scintillators had PSD figures of merit (FoMs) up to 2.77 compared to 3.25 of EJ-276. The 3D-printability of the tested formulations was demonstrated.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Optimization of neutron chopper and optics for CENTAUR, the SANS/WANS diffractometer at the spallation neutron source second target station

Herein this report presents the physics design and optimization of the neutron chopper and optics systems for the CENTAUR instrument, a multifunctional small-angle and wide-angle neutron scattering diffractometer for the Spallation Neutron Source Second Target Station. This instrument will offer a wide range of capabilities, including small-angle neutron scattering with wide Q coverage (e.g., 0.001–20 Å –1 ), providing a tool to investigate structures from atomic to mesoscopic scales simultaneously. To efficiently transport desired neutrons from the compact high-brightness cold source, several innovative designs are utilized: a time-zero chopper with a straight guide system for short-wavelength neutrons, octagonal guides for higher flux, and a correlation chopper to reduce inelastic scattering. The optimization process considers factors such as useable time-integrated flux, instrument resolution, brilliance transfer, divergence, and acceptance diagram uniformity. The overall design prioritizes flexibility to accommodate diverse user requirements.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗