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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 811 records · Page 45
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Steroid receptors and their ligands: Effects on male gamete functions

In recent years a new picture of human sperm biology is emerging. It is now widely recognized that sperm contain nuclear encoded mRNA, mitochondrial encoded RNA and different transcription factors including steroid receptors, while in the past sperm were considered incapable of transcription and translation. One of the main targets of steroid hormones and their receptors is reproductive function. Expression studies on Progesterone Receptor, estrogen receptor, androgen receptor and their specific ligands, demonstrate the presence of these systems in mature spermatozoa as surface but also as nuclear conventional receptors, suggesting that both systemic and local steroid hormones, through sperm receptors, may influence male reproduction. However, the relationship between the signaling events modulated by steroid hormones and sperm fertilization potential as well as the possible involvement of the specific receptors are still controversial issues. The main line of this review highlights the current research in human sperm biology examining new molecular systems of response to the hormones as well as specific regulatory pathways controlling sperm cell fate and biological functions. Most significant studies regarding the identification of steroid receptors are reported and the mechanistic insights relative to signaling pathways, together with the change in sperm metabolism energy influenced by steroid hormones are discussed.The reviewed evidences suggest important effects of Progesterone, Estrogen and Testosterone and their receptors on spermatozoa and implicate the involvement of both systemic and local steroid action in the regulation of male fertility potential. - Highlights: • One of the main targets of steroid hormones and their receptors is reproductive function. • Pg/PR co-work to stimulate enzymatic activities to sustain a capacitation process. • E2/ERs regulate sperm motility, capacitation and acrosome reaction and act as survival factors. • Androgens/AR mediate sperm death which is a novel field of investigation in sperm biology.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2024

Cavity Controlled Upconversion in CdSe Nanoplatelet Polaritons

Exciton-polaritons provide a versatile platform for investigating quantum electrodynamics effects in chemical systems, such as polariton-altered chemical reactivity. However, using polaritons in chemical contexts will require a better understanding of their photophysical properties under ambient conditions, where chemistry is typically performed. Here, we used cavity quality factor to control strong light–matter interactions and in particular the excited state dynamics of colloidal CdSe nanoplatelets (NPLs) coupled to a Fabry– Pérot optical cavity. With increasing cavity quality factor, we observe significant population of the upper polariton (UP) state, exemplified by the rare observation of substantial UP photoluminescence (PL). Excitation of the lower polariton (LP) states results in upconverted PL emission from the UP branch due to efficient exchange of population between the LP, UP and the reservoir of dark states present in collectively coupled polaritonic systems. In addition, we measure time scales for polariton dynamics ~100 ps, implying great potential for NPL based polariton systems to affect photochemical reaction rates. State-of-the-art quantum dynamical simulations show outstanding quantitative agreement with experiments, and thus provide important insight into polariton photophysical dynamics of collectively coupled nanocrystal-based systems. These findings represent a significant step toward the development of practical polariton photochemistry platforms.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Engineering Bacteria to Catabolize the Carbonaceous Component of Sarin: Teaching E. coli to Eat Isopropanol

In this paper, we report an engineered strain of Escherichia coli that catabolizes the carbonaceous component of the extremely toxic chemical warfare agent sarin. Enzymatic decomposition of sarin generates isopropanol waste that, with this engineered strain, is then transformed into acetyl-CoA by enzymatic conversion with a key reaction performed by the acetone carboxylase complex (ACX). We engineered the heterologous expression of the ACX complex from Xanthobacter autotrophicus PY2 to match the naturally occurring subunit stoichiometry and purified the recombinant complex from E. coli for biochemical analysis. Incorporating this ACX complex and enzymes from diverse organisms, we introduced an isopropanol degradation pathway in E. coli, optimized induction conditions, and decoupled enzyme expression to probe pathway bottlenecks. Our engineered E. coli consumed 65% of isopropanol compared to no-cell controls and was able to grow on isopropanol as a sole carbon source. Finally, in the process, reconstitution of this large ACX complex (370 kDa) in a system naïve to its structural and mechanistic requirements allowed us to study this otherwise cryptic enzyme in more detail than would have been possible in the less genetically tractable native Xanthobacter system.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

A Computational-Experimental Study of Plasma Processing of Carbides at High Temperatures

The effects of plasma on carbides were computationally investigated for the ultimate development of adherent, dense scales such as Al 2 O 3 -TiO 2 systems toward oxidation resistance at 1873 K. An alumina scale forms on the carbide because of the significant stability of Al 2 O 3 as the outer scale adjacent to the gas phase compared to rutile, though TiO and Ti 2 O 3 may form as components of an inner layer of a complicated scale. A sequence of surface reactions starting with the adsorption of oxygen on the surface was applied to experimental data from Donnelly’s research group who reported the adsorption of O 2 in a plasma atmosphere as a function of power. In addition to the adsorbed oxygen (Oad) as the rate determining step, it controlled the cascading reaction sequence of the adsorbed species of AlO, AlO 2 and AlO 3 , as indicated in the present study. The rate of oxygen adsorption also depends on the ratio of the final to initial adsorbed oxygen as a function the oxygen potential. In a secondary research thrust, Ti 3 AlC was synthesized and subsequently oxidized. A 39Ti-14Al-47TiC (in wt%) mixture was equilibrated by using a pseudo-isopiestic technique to form ultimately an aggregate of Ti3AlC, Ti 2 AlC and TiC phases. The aggregate was primarily composed of Ti 3 AlC with minor amounts of Ti 2 AlC and TiC, as determined by an X-ray diffraction analysis. The Ti 3 AlC/Ti 2 AlC/TiC aggregate was subsequently oxidized at 1873 K to form a scale composed of an outer layer of Al 2 O 3 -TiO 2 -Al 2 TiO 5 with an inner layer consisting of TiO-Al 2 O 3 - Al 4 CO 3 . The measured scale thickness grew according to Wagner’s parabolic growth rate, which estimates an effective diffusion coefficient of 6 (10)-8 cm 2 /s. The scale appears to grow with Ti ions migrating outward from the Ti 3 AlC/Ti 2 AlC/TiC core and oxygen ions diffusing inwardly toward the core. The transient temperature distribution of a cylindrical, carbide packed bed (i.e., B4C) was simulated with COMSOL software to determine the response of the bed to a sudden temperature spike exposed to the outer wall of the bed. The temperature distribution of B4C was similarly heated and compared with Hf and Zr metal. The thermal conductivity of Hf and Zr is higher than the B4C packed bed and hence they respond quicker than B4C. The packed bed still takes approximately 1200 s to plateau the temperature distribution between the cylinder surfaces to the centerline of the carbide packed bed of 5 cm diameter. Though the modeling of the distributions in the carbide packed bed gives an understanding of the transient heat response behavior driven by radiation, the effect of the plasma on the surface temperature of individual carbide particles needs further investigation to understand the plasma contribution to densification of a carbide packed bed.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Managing Risks via Small/Pilot Scale Testing for INL's Integrated Waste Treatment Unit (IWTU) - 19268

In 2005, the THOR steam reforming fluidized-bed reactor (FBR) technology was selected by the U.S. Department of Energy (DOE) as the technology of choice for treatment of sodium- bearing waste (SBW) at the INL. The basis of the process was to use fluidized bed technology to convert an acidic radioactive nitrate-rich liquid waste into a solid carbonate product suitable for long-term disposal and storage. During initial commissioning, as well as subsequent start-ups, the plant faced many operational challenges, such as stagnant/de-fluidized bed, and wall-scale formation. Such operational issues prompted the original contractor to seek expertise in pilot-scale testing, thereby reaching out to Hazen Research Inc. (HRI, Golden, Co). Several tests were conducted, but the results did not seem to address the underlying issues observed in the full-scale plant, as evidenced by continued operational issues. A systematic approach was then taken by the Fluor-Idaho team (new contractor as of June 2016) with respect to solving these technical issues. First, two different bench-scale, 2-inch fluidized bed reactors (stainless-steal and quartz), were utilized to test several theories to better understand the underlying chemical reactions that may be taking place under expected normal operating conditions. Then, the team designed and built an 18-inch FBR unit, mimicking the full-scale main vessel at IWTU - Denitration Mineralization Reformer (DMR). This was used to test various aspects of operational challenges observed at IWTU, namely particle size control, wall-scale growth-rate control, long-term operational stability, process optimization, and process off- gas filtration challenges. An example of information obtained from bench-scale testing, which was then tested during pilot-scale testing, was the phenomena that an addition of 5 vol % of CO{sub 2} gas into the fluidizing gas system nearly eliminated the formation of agglomerates that had typically led to bed de-fluidization. This change proved to be correct in both the pilot and full-scale testing and will be implemented as part of a long-term operational strategy of IWTU. Several other findings that have provided answers with respect to IWTU operational issues will be discussed in this report. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2025

The spherical tokamak advanced reactor (STAR) fusion power plant design

Scientific and technical advancements have been made that improve fusion’s prospects to provide a new energy source, showing enhanced plasma confinement conditions with plasma temperatures reaching or exceeding 100 million degrees. Overshadowing this progress is the challenge involved in developing an economically viable fusion power plant design. Many proposed next-step DEMO and pilot plant designs are extensions of existing physics-focused experimental devices defined to understand and control plasma operations to achieve and sustain a fusion reaction. Transitioning scientific and technical advancements into a functional power plant requires a dedicated focus on architectural designs that integrate diverse technologies, while optimizing physics conditions, with a focus on economic viability. This holistic approach is essential in turning the promise of fusion energy into a reality. The Spherical Tokamak Advanced Reactor (STAR) is a fusion power plant conceptual design with the architectural focus that strives to balance physics, engineering, and cost considerations. In conclusion, it has been set up to introduce relevant physics, engineering and concept features that an intermediate pilot plant might follow, with the goal of meeting system performances and economic requirements that lead to a commercially competitive fusion power plant.

Blanket segmentation↗
DOE OSTI2021

Continuous Fly-Through High-Temperature Synthesis of Nanocatalysts

Conventional thermal treatment system, such as muffle and tube furnaces, typically feature low ramping and cooling rates, which lead to steep thermal gradients during bulk material synthesis that generate inefficient, non-uniform reaction conditions and result in nanoparticle aggregation. Herein, we demonstrate a continuous fly-through material synthesis approach using a novel high-temperature reactor design based on the emerging thermal-shock technology. By facing two sheets of carbon paper with a small distance apart (1–3 mm), we are able to generate uniform, ultra-high temperatures that can reach up to 3200 K within 50 ms by simply applying a voltage of 15 V. We can control this high-temperature to enable ultrafast chemical reactions by continuously feeding raw materials through the device from one end to the other, allowing the final products to be rapidly collected. As a proof-of-concept demonstration, we synthesized Pt nanocatalysts ~4 nm in size anchored to carbon black via this fly-through high-temperature reactor at ~1400 K. Furthermore, we find these supported Pt nanoparticles feature excellent electrocatalytic activities toward methanol oxidation reaction. Compared to existing heating methods, this continuous fly-through high temperature reactor offers a new and highly efficient platform for the synthesis of nanomaterials at high temperatures.

Qiao, Yun↗
DOE OSTI2017

Synthesis Gas Conversion over Rh-Based Catalysts Promoted by Fe and Mn

Rh/SiO2 catalysts promoted with Fe and Mn are selective for synthesis gas conversion to oxygenates and light hydrocarbons at 523 K and 580 psi. Selective anchoring of Fe and Mn species on Rh nanoparticles was achieved by controlled surface reactions and was evidenced by ultraviolet–visible absorption spectroscopy, scanning transmission electron microscopy, and inductively coupled plasma absorption emission spectroscopy. The interaction between Rh and Fe promotes the selective production of ethanol through hydrogenation of acetaldehyde and enhances the selectivity toward C2 oxygenates, which include ethanol and acetaldehyde. The interaction between Rh and Mn increases the overall reaction rate and the selectivity toward C2+ hydrocarbons. The combination of Fe and Mn on Rh/SiO2 results in trimetallic Rh-Fe-Mn catalysts that surpass the performance of their bimetallic counterparts. The highest selectivities toward ethanol (36.9%) and C2 oxygenates (39.6%) were achieved over the Rh-Fe-Mn ternary system with a molar ratio of 1:0.15:0.10, as opposed to the selectivities obtained over Rh/SiO2, which were 3.5% and 20.4%, respectively. The production of value-added oxygenates and C2+ hydrocarbons over this trimetallic catalyst accounted for 55% of the total products. X-ray photoelectron spectroscopy measurements suggest that significant fractions of the Fe and Mn species exist as metallic iron and manganese oxides on the Rh surface upon reduction. These findings are rationalized by density functional theory (DFT) calculations, which reveal that the exact state of metals on the surfaces is condition-dependent, with Mn present as Mn(I) and Mn(II) oxide on the Rh (211) step edges and Fe present as Fe(I) oxide on the step edge and metallic subsurface iron on both Rh steps and terraces. CO Fourier transform infrared spectroscopy and DFT calculations suggest that the binding of CO to Rh (211) step edges modified by Fe and/or manganese oxide is altered in comparison to CO adsorption on a clean Rh (211) surface. These results suggest that Mn2Ox species and Fe and Fe2O modify bonding at Rh step edges and shift reaction selectivity away from CH4.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Gas-solid interfacial modification of oxygen activity in layered oxide cathodes for lithium-ion batteries

Lattice oxygen can play an intriguing role in electrochemical processes, not only maintaining structural stability, but also influencing electron and ion transport properties in high-capacity oxide cathode materials for Li-ion batteries. Here, we report the design of a gas–solid interface reaction to achieve delicate control of oxygen activity through uniformly creating oxygen vacancies without affecting structural integrity of Li-rich layered oxides. Theoretical calculations and experimental characterizations demonstrate that oxygen vacancies provide a favourable ionic diffusion environment in the bulk and significantly suppress gas release from the surface. The target material is achievable in delivering a discharge capacity as high as 301 mAh g –1 with initial Coulombic efficiency of 93.2%. After 100 cycles, a reversible capacity of 300 mAh g –1 still remains without any obvious decay in voltage. Lastly, this study sheds light on the comprehensive design and control of oxygen activity in transition-metal-oxide systems for next-generation Li-ion batteries.

25 ENERGY STORAGE↗
DOE OSTI2017

Quantitative Determination on Ionic-Liquid-Gating Control of Interfacial Magnetism

Ionic-liquid gating on a functional thin film with a low voltage has drawn a lot of attention due to rich chemical, electronic, and magnetic phenomena at the interface. A key challenge in quantitative determination of voltage-controlled magnetic anisotropy (VCMA) in Au/[DEME] + [TFSI] - /Co field-effect transistor heterostructures is addressed. The magnetic anisotropy change as response to the gating voltage is precisely detected by in situ electron spin resonance measurements. Furthermore, a reversible change of magnetic anisotropy up to 219 Oe is achieved with a low gating voltage of 1.5 V at room temperature, corresponding to a record high VCMA coefficient of ≈146 Oe V -1 . Two gating effects, the electrostatic doping and electrochemical reaction, are distinguished at various gating voltage regions, as confirmed by X-ray photoelectron spectroscopy and atomic force microscopy experiments. Our work shows a unique ionic-liquid-gating system for strong interfacial magnetoelectric coupling with many practical advantages, paving the way toward ion-liquid-gating spintronic/electronic devices.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Reaction–Transport Coupling in a Nanostructured Porous Electrode

The function of nanoporous electrodes involves chemical reactions coupled to transport of reactants and products into and out of the solid matrix. To understand how this coupling can depend on electrode structure and chemistry, a general multiscale, molecular-level computational framework is introduced and applied to a model system containing a nanoporous photoanode, the dye-sensitized solar cell. The pore structure and electrolyte composition are systematically varied to probe this coupling, revealing that in most cases the photocurrent density depends on dye coverage within the anode matrix, the specific architecture of an individual pore, and electrolyte gradients in between the anode and cathode. The large electrolyte gradients that develop in the anode are not kinetically controlling. In conclusion, the computational framework demonstrated is general and can be applied to other electrochemical, photochemical, and thermally driven nanoporous systems to evaluate the fundamental characteristics of their function.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Detonation Wave Dynamics in a Rotating Detonation Engine

Rotating detonation engines have complex unsteady flow fields that have been observed to give rise to multiple wave systems beyond the main detonation wave they are intended to produce. In this work we have developed a new analysis technique we refer to Circuit Wave Analysis to identify and describe the system of waves associated with the reaction fronts that exist in the RDE from time-resolved, high-speed end-view chemiluminescence movies of the reaction fronts. For each wave system, we then extract the speed of the wave, its direction and strength (from a measure of spectral power). Through this approach we have determined that under a range of operating conditions RDE flow fields are characterized by three separate wave systems: the main detonation wave and two secondary wave systems, which, based on their relationship relative to the main detonation wave, we refer to as the counter rotating fast wave and counter rotating slow wave pair, respectively. The properties of all three waves vary with both operation condition (air mass flow rate and equivalence ratio) and the configuration of the air inlet and fuel injector. The controlling mechanisms behind the secondary wave systems are not currently known. However, the impact that secondary waves have on some of the detonation properties can be observed in select cases. For example, the presence of a secondary wave has been observed to correspond with a reduction in detonation wave speed.

Chacon, Fabian↗
DOE OSTI2016

Bench Scale Process for Low Cost CO2 Capture Using a Phase-Changing Absorbent: Topical Report EH&S Risk Assessment

GE Global Research was contracted by the Department of Energy to design and build a bench-scale process for a novel phase-changing aminosilicone-based CO2 capture solvent (award number DEFE0013687). As part of this program, a technology EH&S assessment (Subtask 5.1) has been completed for a CO2 capture system for a 550 MW coal-fired power plant. The assessment focuses on two chemicals used in the process, the aminosilicone solvent, GAP-0, and dodecylbenzenesulfonic acid (DDBSA), the GAP-0 carbamate formed upon reaction of the GAP-0 with CO2, and two potential byproducts formed in the process, GAP-0/SOx salts and amine-terminated, urea-containing silicone (also referred to as “ureas” in this report). The EH&S assessment identifies and estimates the magnitude of the potential air and water emissions and solid waste generated by the process and reviews the toxicological profiles of the chemicals associated with the process. Details regarding regulatory requirements, engineering controls, and storage and handling procedures are also provided in the following sections.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2015

Integrated Waste Treatment Unit (IWTU) Input Coal Analyses and Off-Gass Filter (OGF) Content Analyses

A full engineering scale Fluidized Bed Steam Reformer (FBSR) system is being used at the Idaho Nuclear Technology and Engineering Center (INTEC) to stabilize acidic Low Activity Waste (LAW) known as Sodium Bearing Waste (SBW). The INTEC facility, known as the Integrated Waste Treatment Unit (IWTU), underwent an Operational Readiness Review (ORR) and a Technology Readiness Assessment (TRA) in March 2014. The IWTU began non-radioactive simulant processing in late 2014 and by January, 2015 ; the IWTU had processed 62,000 gallons of simulant. The facility is currently in a planned outage for inspection of the equipment and will resume processing simulated waste feed before commencing to process 900,000 gallons of radioactive SBW. The SBW acidic waste will be made into a granular FBSR product (carbonate based) for disposal in the Waste Isolation Pilot Plant (WIPP). In the FBSR process calcined coal is used to create a CO2 fugacity to force the waste species to convert to carbonate species. The quality of the coal, which is a feed input, is important because the reactivity, moisture, and volatiles (C,H,N,O, and S) in the coal impact the reactions and control of the mineralizing process in the primary steam reforming vessel, the Denitration and Mineralizing Reformer (DMR). Too much moisture in the coal can require that additional coal be used. However since moisture in the coal is only a small fraction of the moisture from the fluidizing steam this can be self-correcting. If the coal reactivity or heating value is too low then the coal feed-rate needs to be adjusted to achieve the desired heat generation. Too little coal and autothermal heat generation in the DMR cannot be sustained and/or the carbon dioxide fugacity will be too low to create the desired carbonate mineral species. Too much coal and excess S and hydroxide species can form. Excess sulfur from coal that (1) is too rich in sulfur or (2) from overfeeding coal can promote wall scale and contribute to corrosion in process piping and materials, in excessive off-gas absorbent loading, and in undesired process emissions. The ash content of the coal is important as the ash adds to the DMR and other vessel products which affect the final waste product mass and composition. The amount and composition of the ash also affects the reaction kinetics. Thus ash content and composition contributes to the mass balance. In addition, sodium, potassium, calcium, sulfur, and maybe silica and alumina in the ash may contribute to wall-scale formation. Sodium, potassium, and alumina in the ash will be overwhelmed by the sodium, potassium, and alumina from the feed but the impact from the other ash components needs to be quantified. A maximum coal particle size is specified so the feed system does not plug and a minimum particle size is specified to prevent excess elutriation from the DMR to the Process Gas Filter (PGF). A vendor specification was used to procure the calcined coal for IWTU processing. While the vendor supplied a composite analysis for the 22 tons of coal (Appendix A), this study compares independent analyses of the coal performed at the Savannah River National Laboratory (SRNL) and at the National Energy Technology Laboratory (NETL). Three supersacks a were sampled at three different heights within the sack in order to determine within bag variability and between bag variability of the coal. These analyses were also compared to the vendor’s composite analyses and to the coal specification. These analyses were also compared to historic data on Bestac coal analyses that had been performed at Hazen Research Inc. (HRI) between 2004-2011.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

New-Generation Carbon-Capture Ionic Liquids Regulated by Metal-Ion Coordination

Development of efficient carbon capture-and-release technologies with minimal energy input is a long-term challenge in mitigating CO 2 emissions, especially via CO 2 chemisorption driven by engineered chemical bond construction. Herein, taking advantage of the structural diversity of ionic liquids (ILs) in tuning their physical and chemical properties, precise reaction energy regulation of CO 2 chemisorption was demonstrated deploying metal-ion-amino-based ionic liquids (MAILs) as absorbents. The coordination ability of different metal sites (Cu, Zn, Co, Ni, and Mg) to amines was harnessed to achieve fine-tuning on stability constants of the metal ion-amine complexes, acting as the corresponding cations in the construction of diverse ILs coupled with CO 2 -philic anions. The as-afforded MAILs exhibited efficient and controllable CO 2 release behavior with great reduction in energy input and minimal sacrifice on CO 2 uptake capacity. This coordination-regulated approach offers new prospects for the development of ILs-based systems and beyond towards energy-efficient carbon capture technologies.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Experimental Investigation of the System Nonmetallic Inclusion-Molten Steel-Refractory System at High Temperatures

In continuous casting, the buildup of particles in the flow control system is called clogging. Clogging may be caused by preexisting nonmetallic inclusions attached to the refractory wall, interrupting or disturbing the fluid flow conditions. The interfacial properties of the nonmetallic inclusion-molten steel-refractory system are believed to play a key role in the clogging tendency of selected steel grades in contact with ceramics. The combination of a high-temperature laser scanning confocal microscope (HT-LSCM), which is employed for in situ observation of inclusions’ behavior in the liquid steel or at the steel/ceramic interface, and a high-temperature drop shape analyzer (HT-DSA), which is utilized for contact angle measurements, enabled the investigation of reactions and interactions in the described system at experimental temperatures of approximately 1600 °C. The objective of this study was to develop a method to obtain qualitative information on the deposition of nonmetallic inclusions (NMIs) in the submerged entry nozzle (SEN) during casting. The behavior of solid NMIs from a calcium-treated steel at the interface between liquid steel and Al{sub 2}O{sub 3} or MgO was investigated by means of HT-LSCM. During the test evaluation, inclusions were found to separate at the steel/ceramic interface due to an attractive force. This force increased with the NMIs’ size as well as with the ceramic particle change. The HT-DSA provided contact angle data between molten steel and the ceramic used for implementation into the theoretical capillary force model. A clear correspondence between the estimated and calculated capillary forces was observed. The change in the wettability of the system, as induced by the change in the ceramic from MgO to Al{sub 2}O{sub 3}, showed a reduction of the attractive forces, indicating a weaker separation toward the SEN for the same inclusion type. This study confirmed the strong potential of wettability investigations to predict the clogging tendency of certain steel grades.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Controlling Solid–Liquid Conversion Reactions for a Highly Reversible Aqueous Zinc–Iodine Battery

Aqueous rechargeable batteries are desirable for many energy storage applications due to their low cost and high safety. However, low capacity and short cycle life are the significant obstacles to their practical applications. Here, we demonstrate a highly reversible aqueous zinc-iodine battery using encapsulated iodine in microporous active carbon fibers (ACFs) as cathode materials through the rational control of solid-liquid conversion reactions. The experiments and density function theory (DFT) calculations were employed to investigate the effects of solvents and properties of carbon hosts, e.g. pore size, surface chemistries, on the adsorption of iodine species. The rational manipulation of the competition between the adsorption in carbon and solvation in electrolytes for iodine species is responsible for the high reversibility and cycling stability. The zinc-iodine batteries deliver a high capacity of 180 mAh g-1 at 1C and a stable cycle life over 3000 cycles with ~90% capacity retention as well as negligible self-discharge. We believe the principles for stabilizing the zinc-iodine system could provide new insight into conversion systems such as Li-S systems.

Environmental Molecular Sciences Laboratory↗
DOE OSTI2023

Tuning hydrogenation chemistry of Pd-based heterogeneous catalysts by introducing homogeneous-like ligands

Abstract Noble metals have been extensively employed in a variety of hydrotreating catalyst systems for their featured functionality of hydrogen activation but may also bring side reactions such as undesired deep hydrogenation. It is crucial to develop a viable approach to selectively inhibit side reactions while preserving beneficial functionalities. Herein, we present modifying Pd with alkenyl-type ligands that forms homogeneous-like Pd-alkene metallacycle structure on the heterogeneous Pd catalyst to achieve the selective hydrogenolysis and hydrogenation. Particularly, a doped alkenyl-type carbon ligand on Pd-Fe catalyst is demonstrated to donate electrons to Pd, creating an electron-rich environment that elongates the distance and weakens the electronic interaction between Pd and unsaturated C of the reactants/products to control the hydrogenation chemistry. Moreover, high H 2 activation capability is maintained over Pd and the activated H is transferred to Fe to facilitate C-O bond cleavage or directly participate in the reaction on Pd. The modified Pd-Fe catalyst displays comparable C-O bond cleavage rate but much higher selectivity (>90%) than the bare Pd-Fe (<50%) in hydrotreating of diphenyl ether (DPE, modelling the strongest C-O linkage in lignin) and enhanced ethene selectivity (>90%) in acetylene hydrogenation. This work sheds light on the controlled synthesis of selective hydrotreating catalysts via mimicking homogeneous analogues.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗