Search NASA⌕ Search

SEARCH · Search NASA

Results for “synthesis and processing”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Atomic Layer Deposition with TiO2 for Enhanced Reactivity and Stability of Aromatic Hydrogenation Catalysts

Hydrogenation of aromatic molecules in fossil- and bio-derived fuels is essential for decreasing emissions of harmful combustion products and addressing growing concerns around urban air pollution. In this work, we used atomic layer deposition to significantly enhance the hydrogenation performance of a conventional supported Pd catalyst by applying an ultrathin coating of TiO2 in a scalable powder coating process. The TiO2-coated catalyst showed substantial gains in the conversion of multiple aromatic molecules, including a 5-fold improvement in turnover frequency versus the uncoated catalyst in the hydrogenation of naphthalene. This activity enhancement was maintained upon scaling the coating synthesis process from 3 to 100 g. Based on the results from Xray photoelectron spectroscopy, X-ray absorption spectroscopy, and computational modeling, the activity enhancement was attributed to ensemble effects resulting from partial TiO2 coverage of the Pd surface rather than fundamental changes to the Pd electronic structure. Additional durability testing confirmed that the TiO2 coating improved the thermal and hydrothermal stability of the catalyst as well as tolerance toward sulfur impurities in the reactant stream. Using an economic model of an industrial deep hydrogenation process, we found that an increase in catalyst activity or lifetime of 2× would justify even a relatively high estimate for the cost of TiO2 atomic layer deposition coatings at scale

atomic layer↗
NASA NTRS2001

Reverse Micelle Based Synthesis of Microporous Materials in Microgravity

Microporous materials include a large group of solids of varying chemical composition as well as porosity. These materials are characterized by channels and cavities of molecular dimensions. The framework structure is made up of interconnecting T-O-T' bonds, where T and T' can be Si, Al, P, Ga, Fe, Co, Zn, B and a host of other elements. Materials with Si-O-Al bonding in the framework are called zeolites and are extensively used in many applications. Ion-exchange properties of these materials are exploited in the consumer and environmental industries. Chemical and petroleum industries use zeolites as catalysts in hydrocarbon transform ations. Synthesis of new microporous frameworks has led to the development of new technologies, and thus considerable effort worldwide is expended in their discovery. Microporous materials are typically made under hydrothermal conditions. Influence of nature of starting reactants, structure directing agents, pH, temperature, and aging all have profound influence on the synthesis process. This is primarily because the most interesting open frameworks are not necessarily the stable structures in the reaction medium. Thus, the discovery of new frameworks is often tied to finding the right composition and synthesis conditions that allow for kinetic stabilization of the structure. This complexity of the synthesis process and limited understanding of it has made it difficult to develop directed is of microporous materials and most advances in this field have been made by trial and error. The basic issues in crystal growth of these materials include: (1) Nature of the nucleation process; (2) Molecular structure and assembly of nuclei; (3) Growth of nuclei into crystals; (4) Morphology control; and (5) Transformation of frameworks into other structures. The NASA-funded research described in this paper focuses on all the above issues and has been described in several publications. We present the highlights of our program, especially with the focus on possible experiments in microgravity.

Dutta, Prabir K.↗
DOE OSTI2024

Innovations in Direct Air Capture: Unveiling a Simple and Robust Synthesized Fibrous Amine-functionalized Matrix (FAM) Sorbent for Commercial Scale-up

The escalating challenge of climate change necessitates innovative solutions in the realm of carbon management, particularly in mitigating the impact of fossil fuel emissions. Direct Air Capture (DAC) technology emerged as a critical component within the spectrum of Carbon Capture and Sequestration (CCS) solutions, offering the distinct advantage of directly removing CO2 from the atmosphere irrespective of the source. This attribute grants DAC systems unparalleled flexibility in deployment locations and the potential to make substantial contributions to lowing atmospheric CO2 levels. The success of DAC technologies significantly depends on the development of an efficient, economical sorbent capable of selective and durable CO2 capture from ambient air. Recent advancements in material science have led to the exploration of amine-functionalized sorbents, hollow fiber sorbents and membranes, and other novel materials designed to meet these criteria. This study explores a novel Fibrous Amine-functionalized Matrix (FAM) sorbent. The FAM sorbent distinguished itself through its mechanical robustness, a streamlined synthesis process, and the capability for low-temperature regeneration (is 90 oC really low temperature?). FAM’s exceptional adsorption-desorption kinetics enable swift CO2 capture and release, crucial for the viability of DAC on a commercial scale. The synthesis process involves a simple dip-coating technique, allowing crosslinked amines to coat glass substrates.

Wang, Qiuming↗
DOE OSTI2019

Understanding the effects of oxygen defects on the redox reaction pathways in LiVPO 4 F by combining ab initio calculations with experiments

Tavorite LiVPO 4 F has great potential as a cathode material due to its high energy density, superior thermal stability and fast kinetics. It has been controversial whether the redox reaction pathway of LiVPO 4 F is symmetric or not, but the origin of such symmetric/asymmetric redox reaction pathways has not been clearly understood. By combining ab initio calculations with experiments, we found that oxygen defects on fluorine sites, O F -, can be a key factor that affects the symmetry of the redox pathway of LiVPO 4 F 1-δ O δ (δ < 1). The computational results indicate that (1) the thermodynamically metastable ‘triclinic’ polymorph of VPO 4 F 1-δ O δ , which maintains the structural symmetry of LiVPO 4 F, can be kinetically stabilized considering its marginally higher energy than the stable ‘monoclinic’ phase; and (2) the O F - defects slightly destabilize the intermediate phase ( x = 0.667) (Li 0.667 VPO 4 F versus Li 0.667 VPO 4 F 0.917 O 0.083 ), inferring that the presence of O F - defects can induce the asymmetric redox pathway of LiVPO 4 F 1-δ O δ . We also experimentally found that the concentration of O F - defects is critically affected by the synthesis process of LiVPO 4 F, and VPO 4 F with lower O F - concentration can support the possible presence of the metastable (triclinic) phase, leading to the redox pathway being prone to being symmetric. Therefore, controlling oxygen defects by a synthesis processes can affect electrochemical performance via different redox reaction pathways of LiVPO 4 F. This understanding provides further possibilities for improving the electrochemical performance.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1989

Reuse at the Software Productivity Consortium

The Software Productivity Consortium is sponsored by 14 aerospace companies as a developer of software engineering methods and tools. Software reuse and prototyping are currently the major emphasis areas. The Methodology and Measurement Project in the Software Technology Exploration Division has developed some concepts for reuse which they intend to develop into a synthesis process. They have identified two approaches to software reuse: opportunistic and systematic. The assumptions underlying the systematic approach, phrased as hypotheses, are the following: the redevelopment hypothesis, i.e., software developers solve the same problems repeatedly; the oracle hypothesis, i.e., developers are able to predict variations from one redevelopment to others; and the organizational hypothesis, i.e., software must be organized according to behavior and structure to take advantage of the predictions that the developers make. The conceptual basis for reuse includes: program families, information hiding, abstract interfaces, uses and information hiding hierarchies, and process structure. The primary reusable software characteristics are black-box descriptions, structural descriptions, and composition and decomposition based on program families. Automated support can be provided for systematic reuse, and the Consortium is developing a prototype reuse library and guidebook. The software synthesis process that the Consortium is aiming toward includes modeling, refinement, prototyping, reuse, assessment, and new construction.

Weiss, David M.↗
DOE OSTI2023

The Role of SnO2 Processing on Ionic Distribution in Double-Cation-Double Halide Perovskites

Moving toward a future of efficient, accessible, and less carbon-reliant energy devices has been at the forefront of energy research innovations for the past 30 years. Metal-halide perovskite (MHP) thin films have gained significant attention due to their flexibility of device applications and tunable capabilities for improving power conversion efficiency. Serving as a gateway to optimize device performance, consideration must be given to chemical synthesis processing techniques. Therefore, how does common substrate processing techniques influence the behavior of MHP phenomena such as ion migration and strain? Here, we demonstrate how a hybrid approach of chemical bath deposition (CBD) and nanoparticle SnO2 substrate processing significantly improves the performance of (FAPbI3)0.97(MAPbBr3)0.03 by reducing micro-strain in the SnO2 lattice, allowing distribution of K+ from K-Cl treatment of substrates to passivate defects formed at the interface and produce higher current in light and dark environments. X-ray diffraction reveals differences in lattice strain behavior with respect to SnO2 substrate processing methods. Through use of conductive atomic force microscopy (c-AFM), conductivity is measured spatially with MHP morphology, showing higher generation of current in both light and dark conditions for films with hybrid processing. Additionally, time-of-flight secondary ionization mass spectrometry (ToF-SIMS) observed the distribution of K+ at the perovskite/SnO2 interface, indicating K+ passivation of defects to improve the power conversion efficiency (PCE) and device stability. We show how understanding the role of ion distribution at the SnO2 and perovskite interface can help reduce the creating of defects and promote a more efficient MHP device.

conductive atomic force microscopy↗
NASA NTRS2016

Low Temperature Regolith Bricks for In-Situ Structural Material

Current technology for producing in-situ structural materials on future missions to Mars or the moon relies heavily on energy-intensive sintering processes to produce solid bricks from regolith. This process requires heating the material up to temperatures in excess of 1000 C and results in solid regolith pieces with compressive strengths in the range of 14000 to 28000 psi, but are heavily dependent on the porosity of the final material and are brittle. This method is currently preferred over a low temperature cementation process to prevent consumption of precious water and other non-renewable materials. A high strength structural material with low energy requirements is still needed for future colonization of other planets. To fulfill these requirements, a nano-functionalization process has been developed to produce structural bricks from regolith simulant and shows promising mechanical strength results. Functionalization of granular silicate particles into alkoxides using a simple low temperature chemical process produces a high surface area zeolite particles that are held together via inter-particle oxygen bonding. Addition of water in the resulting zeolite particles produces a sol-gel reaction called "inorganic polymerization" which gives a strong solid material after a curing process at 60 C. The aqueous solution by-product of the reaction is currently being investigated for its reusability; an essential component of any ISRU technology. For this study, two batches of regolith bricks are synthesized from JSC-1A; the first batch from fresh solvents and chemicals, the second batch made from the water solution by-product of the first batch. This is done to determine the feasibility of recycling necessary components of the synthesis process, mainly water. Characterization including BET surface area, SEM, and EDS has been done on the regolith bricks as well as the constituent particles,. The specific surface area of 17.53 sq m/g (average) of the granular regolith material was obtained from nitrogen adsorption isotherm measurement. The size, shape and textures of regolith from SEM shows that the particles are 25-50 micrometers in size and mostly irregular in shape (Figure 1a). The elemental composition of regolith was identified from EDS analysis showed the presence of Si, Al, Fe, Na, Mg, Ca, Ti, O and C (see figure 1b). Each set of cylindrical brick samples were prepared by low energy process, and cured for 21 and 28 days, respectively to compare their compressive strength. Figure 1c, and d shows the JSC-1A brick and the compressive strength measurements. The results from the 21 day cured bricks (2 bricks) have been done and yielded an aver-age strength of 3050 psi, considerably higher than Portland cement mortars (Type IV and V). This promising technology provides the benefits of construction material similar to concrete, with a low complexity, low energy synthesis process and the likelihood of complete reusability of precious resources. Compressive strength using this method can be improved by increasing the surface area of the particles, using bi-modal particle size distribution, and adding certain additives to increase inter-particle forces.

ISRU↗
DOE OSTI2018

Stable-carbon isotope ratios for sourcing the nerve-agent precursor methylphosphonic dichloride and its products

The ability to connect a chemical threat agent to a specific batch of a synthetic precursor can provide a fingerprint to contribute to effective forensic investigations. Stable isotope analysis can leverage intrinsic, natural isotopic variability within the molecules of a threat agent to unlock embedded chemical fingerprints in the material. Methylphosphonic dichloride (DC) is a chemical precursor to the nerve agent sarin. It is converted to methylphosphonic difluoride (DF) as part of the sarin synthesis process. We used a suite of commercially available DC stocks to both evaluate the potential for δ13C analysis to be used as a fingerprinting tool in sarin-related investigations and to develop sample preparation techniques (using chemical hydrolysis) that can simplify isotopic analysis of DC and its synthetic products. We demonstrate that natural isotopic variability in DC results in at least three distinct, isotope-resolved clusters within the thirteen stocks we analyzed. Isotopic variability in the carbon feedstock (i.e., methanol) used for DC synthesis is likely inherited by the DC samples we measured. We demonstrate that the hydrolysis of DC and DF to methylphosphonic acid (MPA) can be used as a preparative step for isotopic analysis because the reaction does not impart a measureable isotopic fractionation. MPA is more chemically stable, less toxic, and easier to handle than DC or DF. Further, the hydrolysis method we demonstrated can be applied to a suite of other precursors or to sarin itself, thereby providing a potentially valuable forensic tool.

Moran, James J.↗
DOE OSTI2019

Systematic Process Intensification involving Zeotropic Distillation

Distillation is commonly used for separating homogeneous fluid mixtures. While it is based on a simple thermally driven vapor-liquid equilibrium phenomenon at the two-phase region, different variants of distillation systems exist. These include simple distillation, dividing wall columns, pressure swing distillation, thermally coupled distillation and reactive distillation. Complex separation may also involve multiple distillation in a sequence to achieve the desired products. These sequences can be constructed as direct sequence, indirect sequence or thermally coupled columns. Even when a sequence is fixed, each column in the sequence can have a plethora of design alternatives to consider. All these make the design and intensification of distillation systems a challenging task. The large number of plausible design alternatives increases the combinatorial complexity for screening. Although significant efforts have been made in the past, we still lack a method for systematic identification of novel pathways for process intensification of distillation system. This is due to the lack of a generalized representation of all plausible alternatives in a single modeling and optimization framework. In this work, we first present a general representation of thermally driven vapor-equilibrium phenomenon using abstract building blocks. Specifically, each tray in a distillation column is represented by a liquid block and a vapor block with a shared semi-restricted boundary representing the interface. The arrangement of these building blocks in a two-dimensional grid gives rise to all plausible variants of distillation systems. These systems range from simple distillation, dividing wall columns to task-integrated columns. This enables us to systematically identify both classic and out-of-the-box intensified designs at the column and flowsheet levels. The overall distillation-based separation process synthesis problem is formulated as a single mixed-integer nonlinear programming (MINLP) model. In conclusion, the proposed approach is applied to multi-component zeotropic systems to show the capability of identifying promising intensified alternatives.

42 ENGINEERING↗
DOE OSTI2016

The effect of B{sub 2}O{sub 3} flux on growth NLBCO superconductor by solid state reaction and wet-mixing methods

The synthesis of B{sub 2}O{sub 3} flux substituted NLBCO superconductor NdBa{sub 1.75}La{sub 0.25}Cu{sub 3}O{sub 7-∂} has been done using solid state reaction and wet-mixing methods in order to obtain homogeneous crystals and single phase. From DTA/TGA characteritations showed the synthesis process by wet-mixing requires a lower temperature than the solid state reaction in growing the superconductor NdBa{sub 1.75}La{sub 0.25}Cu{sub 3}O{sub 7-∂}. Therefore, in this research NdBa{sub 1.75}La{sub 0.25}Cu{sub 3}O{sub 7-∂} sample calcinated at 650°C for wet-mixing method and 820°C for solid state reaction methods. The all samples was sintered at 950°C for ten hours. Crystallinity of the sample was confirmed using X-ray techniques and generally obtained sharp peaks that indicates the sample already well crystallized. Search match analyses for diffraction data gave weight fractions of impurity phase of the solid state reaction method higher than wet-mixing method. In this research showed decreasing the price of the lattice parameter about 1% with the addition of B{sub 2}O{sub 3} flux for the both synthesis process and 2% of wet mixing process for all samples. Characterization using scanning electron microscopy (SEM) showed the distribution of crystal zise for wet-mixing method more homogeneous than solid state reaction method, with he grain size of samples is around 150–250 nm. The results of vibrating sample magnetometer (VSM) showed the paramagnetic properties for all samples.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Efficacy of a Solution-Based Approach for Making Sodalite Waste Forms for an Oxide Reduction Salt Utilized in the Reprocessing of Used Uranium Oxide Fuel

This paper describes various approaches for making sodalite with a LiCl-Li2O oxide reduction salt used to recover uranium from used oxide fuel. The approaches include sol-gel and solution-based synthesis processes. As-made products were mixed with 5 and 10 mass% of a Na2O-B2O3-SiO2 glass binder and these, along with product without a binder, were heated using either a cold-press-and-sinter method or hot uniaxial pressing. The results demonstrate the limitation of sodalite yield due to the fast intermediate reactions between Na+ and Cl- to form halite in solution and Li2O and SiO2 to form lithium silicates (e.g., Li2SiO3 or Li2Si2O5) in the calcined and sintered pellets. The results show that pellets can be made with high sodalite fractions (~92 mass%) and low porosities using a solution-based approach and this LiCl-Li2O salt.

electrochemical↗
DOE OSTI2013

Dielectric property of NiTiO{sub 3} doped substituted ortho-chloropolyaniline composites

Ortho-chloropolyaniline (OCP)-NiTiO{sub 3} composites have been synthesized via in-situ polymerization of ortho-chloroaniline with various weight percentages of NiTiO{sub 3.} Fourier Transform Infrared spectroscopic studies of Ortho-chloropolyaniline and its composites indicated the formation of composites as a result of Vander Waal's interaction between OCP and NiTiO{sub 3} particles. Surface morphology of OCP and OCP-NiTiO{sub 3} composites were studied using Scanning Electron Microscope (SEM). The SEM micrographs indicated a modified morphology after the composite formation. Dielectric properties and electric modulus of OCP and OCP-NiTiO{sub 3} composites have been investigated in the frequency range of 50 Hz – 5 MHz. It has been noticed that electrical resistance decreases with increase in weight percentage of NiTiO{sub 3} particles in polymer matrix as well as with applied frequency. The display of semicircular arcs in Cole-Cole plots indicates the formation of series resistor and capacitor in network causing a decrease in the relaxation time and as a result conductivity enhances in these composites. The facile and cost effective synthesis process and excellent dielectric and conductivity response of these materials makes them promising materials for practical applications.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Electronic structure and magnetic properties of LiMn{sub 1.5}M{sub 0.5}O{sub 4} (M=Al, Mg, Ni, Fe) and LiMn{sub 2}O{sub 4}/TiO{sub 2} nanocrystalline electrode materials

The process of sol–gel synthesis was applied to obtain LiMn{sub 1.5}M{sub 0.5}O{sub 4} (M=Al, Mg, Ni, Fe) and LiMn{sub 2}O{sub 4}/TiO{sub 2} nanopowders. The samples were characterized by following methods: X-ray diffraction (XRD), scanning electron microscopy (SEM/EDX), X-ray photoelectron spectroscopy (XPS) and SQUID magnetometry. XPS was used to examine the chemical composition and oxidation state of manganese, in particular the Mn{sup 3+}/Mn{sup 4+} ratio from the deconvolution of the complex Mn3p lines. The size of the grains and crystallites were independently obtained from SEM images and XRD patterns, respectively. In all the cases a critical interplay of electronic (Mn{sup 3+}/Mn{sup 4+} ratio), structural (unit cell volume) and magnetic properties was observed depending on the synthesis process. - Graphical abstract: SEM image of Li{sub 0.79}Ni{sub 0.41}Mn{sub 1.35}O{sub 4.45} sample. Display Omitted - Highlights: • LiMn{sub 1.5}M{sub 0.5}O{sub 4} (M=Al, Mg, Ni, Fe) and LiMn{sub 2}O{sub 4}/TiO{sub 2} obtained by sol–gel method. • XRD method was used to determine the crystal structure. • SEM/EDX imaging have been done. • XPS electronic structure was examined and discussed. • Experimental effective magnetic moment and the calculated one were compared.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2005

Processing and Synthesis of Pre-Biotic Chemicals in Hypervelocity Impacts

Hypervelocity impacts (HVIs) may have played a significant role in establishing the initial organic inventory for pre-biotic chemistry on the Earth and other planetary bodies. In addition to the delivery of organic compounds intact to planetary surfaces, generally at velocities below approx.20 km/s, HVIs also enable synthesis of new molecules. The cooling post-impact plasma plumes of HVIs in the interstellar medium (ISM), the protosolar nebula (PSN), and the early solar system comprise pervasive conditions for organic synthesis. Such plasma synthesis (PS) can operate over many length scales (from nm-scale dust to planets) and energy scales (from molecular rearrangement to atomization and recondensation). HVI experiments with the flexibility to probe the highest velocities and distinguish synthetic routes are a high priority to understand the relevance of PS to exobiology. We describe here recent studies of PS at small spatial scales and extremely high velocities with pulsed laser ablation (PLA). PLA can simulate the extreme plasma conditions generated in impacts of dust particles at speeds of up to 100 km/s or more. When applied to carbonaceous solids, new and pre-biotically relevant molecular species are formed with high efficiency [1,2].

Brickerhoff, W. B.↗