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DOE OSTI2023

Field‐scale analysis of miscanthus production indicates climate change may increase the opportunity for water quality improvement in a key Iowa watershed

Abstract The Raccoon River Basin is the primary source for drinking water in Iowa's largest city and plays a major role in the Mississippi River Basin's high nutrient exports. Future climate change may have major impacts on the biological, physiological, and agronomic processes imposing a threat to ecosystem services. Efforts to reduce nitrogen (N) loads within this basin have included local litigation and the implementation of the Iowa Nutrient Reduction Strategy, which suggest incorporating bioenergy crops (i.e., miscanthus) within the current corn–soybean landscape to reach a 41% reduction in nitrate loads. This study focuses on simulating N export for historical and future land use scenarios by using an agroecosystem model (Agro‐IBIS) and a hydrology model (THMB) at the 500‐m resolution, similar to the scale of agricultural fields. Model simulations are driven by CMIP5 climate data for historical, mid‐century, and late‐century under the RCP 4.5 and 8.5 warming projections. Using recent crop profit analyses for the state of Iowa, profitability maps were generated and nitrogen leaching thresholds were used to determine where miscanthus should replace corn–soybean area to maximize reductions in N pollution. Our results show that miscanthus inclusion on low profit and high N leaching areas can result in a 4% reduction of N loss under current climate conditions and may reduce N loss by 21%–26% under future climate conditions, implying that water quality has the potential continue to improve under future climate conditions when strategically implemented conservation practices are included in future farm management plans.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2020

Hydration and reaction mechanisms on sodium silicate glass surfaces from molecular dynamics simulations with reactive force fields

Recent development of reactive force fields have enabled molecular dynamics simulations of interactions between silicate glasses and water at the atomistic scale. While multicomponent silicate glasses encompass a wide variety of compositions and properties, one common structural feature in these glasses is the combination of the network structure that is made up of silica tetrahedra linked through corner sharing interspersed with network modifiers like alkali and alkaline-earth ions that break up the Si–O–Si linkages by forming nonbridging oxygen. In reactions with water, ion exchange between alkali ions in the glass and proton or hydronium in the solution, as well as hydrolysis reaction of the Si–O–Si linkages and subsequent silanol formation, is observed and well documented. Furthermore, we have used a set of recently developed reactive force field to investigate the reactions between water and the surfaces of silica and sodium silicate glasses of different compositions for reactions up to 8 nanoseconds. Our results indicate sodium leaching into water and diffusion of water molecules up to 25 Å into the glass surface. We examined the structural and compositional changes inside the glass and around the diffused ions and use these to explain the rates of silanol formation at the surface. We also observed proton transport in the glass which has an indirect influence on the silanol formation rates. While the surface of the glass was rough to start with, it undergoes further modification into a hydrated gel-like structure in the glass for up to 5 Å in the higher alkali containing glasses. It was found that the leached sodium ions remain close to the interface and that fragments of silicate network from the surface is capable of dislodging from the bulk glass and enter the aqueous solution. These simulations thus provide insights into the formation and structure of an alteration layers commonly observed in multicomponent silicate glasses corroded in aqueous solutions.

36 MATERIALS SCIENCE↗

DOE OSTI2021

High-Current Density Durability of Pt/C and PtCo/C Catalysts at Similar Particle Sizes in PEMFCs

The durability of carbon supported PtCo-alloy based nanoparticle catalysts play a key role in the longevity of proton-exchange membrane fuel cells (PEMFC) in electric vehicle applications. To improve its durability, it is important to understand and mitigate the various factors that cause PtCo-based cathode catalyst layers (CCL) to lose performance over time. These factors include i) electrochemical surface area (ECSA) loss, ii) specific activity loss, iii) H + /O 2 -transport changes and iv) Co 2+ contamination effects. We use a catalyst-specific accelerated stress test (AST) voltage cycling protocol to compare the durability of Pt and PtCo catalysts at similar average nanoparticle size and distribution. Our studies indicate that while Pt and PtCo nanoparticle catalysts suffer from similar magnitudes of electrochemical surface area (ECSA) losses, PtCo catalyst shows a significantly larger cell voltage loss at high current densities upon durability testing. The distinctive factor causing the large cell voltage loss of PtCo catalyst appears to be the secondary effects of the leached Co 2+ cations that contaminate the electrode ionomer. A 1D performance model has been used to quantify the cell voltage losses arising from various factors causing degradation of the membrane electrode assembly (MEA).

08 HYDROGEN↗

DOE OSTI2023

Baselining Activity and Stability of ORR Catalysts and Electrodes for Proton Exchange Membrane Fuel Cells for Heavy-Duty Applications

Activity and stability of electrodes with Pt and PtCo alloy catalysts supported on high surface area carbon, hereafter to as a-Pt/C and d-PtCo/C, were evaluated for heavy-duty applications. Both catalysts had nearly identical Pt loading (50-wt% Pt on carbon and 0.25 mg Pt cm −2 ) and had undergone thermal treatment to stabilize them by growing the average particle size to 4–5 nm. Both were subjected to 90,000 (90 k) standard accelerated stress tests (AST) cycles consisting of 0.6–0.95 V square wave potentials, 3-s hold at upper and lower potential limits in H 2 /N 2 at 1.5 atm, 80 °C and 100% RH. Test protocols were developed to monitor the performance losses and characterize them in terms of activity for the oxygen reduction reaction (ORR), oxygen transport in the electrode and proton transport in the membrane and cathode catalyst layer. Despite the nearly double initial ORR activity, the PtCo/C electrode degraded faster due to the leaching of Co from the catalyst that had started even before the imposition of the AST potential cycles. Commensurate with Co leaching, Co poisoning of ionomer is responsible for the inferior performance of d-PtCo/C electrode at high current densities both before and after AST.

30 DIRECT ENERGY CONVERSION↗

DOE OSTI2024

Direct Recycling of End-of-Life Cathode Material Through Redox Chemistry Mediators

Lithium-ion batteries (LIBs) are ideal for electric vehicles and electronic devices because of their high-power density and outstanding cycle life. The need for recycled LIBs material is pivotal for the sustainability of the renewable energy industry. The recycling process needs to be both economically and environmentally conscious. Direct recycling is cheaper and generates the least amount of waste compared to pyrometallurgical and hydrometallurgical processes. Direct recycling explored in this work is useful for reclaiming precious minerals from the End-of-Life (EOL) LIBs material. The EOL material has varying lithium deficiency, hence, redox mediator relithiation restores the lithium content rapidly and at low cost. The redox mechanism relithiate EOL cathode material by shuttling charges very fast between lithium metal and EOL cathode material. The redox mediator is oxidized to create lithium rich solvent and reduced to relithiate EOL cathode material. However, the process is sensitive to pH changes. The redox reaction creates acidic solvent, which may cause lithium leaching. Therefore, use of lithium hydroxide (LiOH) to remove impurities on the surface of the EOL material and as a lithium source creates a basic solution to prevent lithium leaching and relithiate EOL material. This approach will potentially pave way for fast quality cathode material recovery at a low cost.

cathode material↗

DOE OSTI2024

SANSMIC v.1.0

SAND2024-01036O The updated Sandia Solution Mining Code (SANSMIC) modeling software models the dissolution of underground salt cavern walls due to raw-water injection (leaching), assuming an oil blanket. A previous version of this software modeled the impacts of leaching at the Strategic Petroleum Reserve and has been used in research for several decades, but the source code was not available. The new version will enhance current research as additional subsurface storage of energy in solution-mined caverns increases. It will also allow research reproducibility by making the software available to the wider research community. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

Hart, David↗

DOE OSTI2026

Data for Genetic Variation in Zea mays Influences Microbial Nitrification and DeNitrification in Conventional Agroecosystems

Nitrogenous fertilizers provide a short-lived benefit to crops in agroecosystems, but stimulate nitrification and denitrification, processes that result in nitrate pollution, N2O production, and reduced soil fertility. Recent advances in plant microbiome science suggest that genetic variation in plants can modulate the composition and activity of rhizosphere N-cycling microorganisms. Here we attempted to determine whether genetic variation exists in Zea mays for the ability to influence the rhizosphere nitrifier and denitrifier microbiome under “real-world” conventional agricultural conditions. To capture an extensive amount of genetic diversity within maize we grew and sampled the rhizosphere microbiome of a diversity panel of germplasm that included ex-PVP inbreds ( Z. mays ssp. mays ), ex-PVP hybrids ( Z. mays ssp. may s), and teosinte ( Z. mays ssp. mexicana and Z. mays ssp. parviglumis ). From these samples, we characterized the microbiome, a suite of microbial genes involved in nitrification and denitrification and carried out N-cycling potential assays. Here we are showing that populations/genotypes of a single species can vary in their ecological interaction with denitrifers and nitrifers. Some hybrid and teosinte genotypes supported microbial communities with lower potential nitrification and potential denitrification activity in the rhizosphere, while inbred genotypes stimulated/did not inhibit these N-cycling activities. These potential differences translated to functional differences in N2O fluxes, with teosinte plots producing less GHG than maize plots. Taken together, these results suggest that Zea genetic variation can lead to changes in N-cycling processes that result in N leaching and N2O production, and thereby are selectable targets for crop improvement. Understanding the underlying genetic variation contributing to belowground microbiome N-cycling into our conventional agricultural system could be useful for sustainability.

Nitrogen↗

DOE OSTI2021

Influence of Agricultural Managed Aquifer Recharge (AgMAR) and Stratigraphic Heterogeneities on Nitrate Reduction in the Deep Subsurface

This data package contains input files for TOUGHREACT for a modeling study examining the effects of managed aquifer recharge on agricultural lands on nitrate cycling and transport in the Central Valley of CA near Modesto. The files contain all the geochemical species, reactions, and hydrological parameters for the model. The files are text files used for the TOUGH family of code created by LBNL. To use the files a license is required. https://tough.lbl.gov/licensing-download/toughreact-licensing-download/Accompanying Paper Abstract: Agricultural managed aquifer recharge (AgMAR) is a proposed management strategy whereby surface water flows are used to intentionally flood croplands with the purpose of recharging underlying aquifers. However, legacy nitrate (NO3-) contamination in agriculturally-intensive regions poses a threat to groundwater resources under AgMAR. To address these concerns, we use a reactive transport modeling framework to better understand the effects of AgMAR management strategies (i.e., by varying the frequency, duration between flooding events, and amount of water) on N leaching to groundwater under different stratigraphic configurations and antecedent moisture conditions. In particular, we examine the potential of denitrification and nitrogen retention in deep vadose zone sediments (~15 m) using variable AgMAR application rates on two-dimensional representations of differently textured soils, soils with discontinuous bands/channels, and soils with preferential flow paths characteristic of typical agricultural field sites. Our results indicate that finer textured sediments, such as silt loams, alone or embedded within high flow regions, are important reducing zones providing conditions needed for denitrification. Simulation results further suggest that applying water all-at-once rather than in increments for a fixed volume of recharge transports higher concentrations of NO3- deeper into the profile, which has the potential to exacerbate groundwater quality. This transport into deeper depths can be aggravated by wetter antecedent soil moisture conditions. However, applying water all-at-once also increases denitrification within the vadose zone by promoting anoxic conditions. We conclude that AgMAR management strategies can be designed to enhance denitrification in the subsurface and reduce N leaching to groundwater, while specifically accounting for lithologic heterogeneity, antecedent soil moisture conditions, and depth to the water table. Our findings are potentially relevant to other systems that experience flooding inundation such as riparian corridors, floodplains, wetlands, and other managed landscapes like dedicated recharge basins.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2020

Nanoscale TiO 2 coating improves water stability of Cs 2 SnCl 6

To improve the stability of Cs 2 SnCl 6 under aqueous/moisture environments, we applied a concept of artificial passivation by depositing a protective TiO 2 coating of 10 nm on the surface of Cs 2 SnCl 6 . Static leaching experiments results indicate that the initial release rates of Cs + and Cl - are decreased by 20–30 times with TiO 2 coating, suggesting its possibility to improve the short-term water/environmental stability of Cs 2 SnCl 6 . An amorphous-to-crystalline phase transition in TiO 2 film was observed, possibly resulting in degradation of Cs 2 SnCl 6 . However, the crystalline TiO 2 film still remains after 21 days water exposure and can still act as an effective passivation layer to reduce the release rates of Cs + and Cl - by as much as about 17 and 7 times, respectively, relative to static leaching without artificial coatings. Therefore, the water/environmental stability of metal halide perovskite Cs 2 SnCl 6 , which is a highly soluble molecular salt, can be enhanced by the nanoscale TiO 2 coating as an artificial passivation film.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2020

Recovery of Rare Earth Elements (REEs) from Coal Mine Drainage, Phase 2

Phase 1 research identified a two-step refining train, acid leaching of AMD precipitate feed followed by solvent extraction (SX), to produce a 2% TREE product. For the Phase 2 bench scale system, the objective was to get the acid leaching step to operate in batch-mode with sufficient storage capacity to feed an aqueous, enriched REE liquor to a pilot SX plant operating in continuous-mode at a feed rate capable of producing 3 g/hr 2% TREE. Important process variables included feed rate, extractant makeup, flowsheet configuration, and stripping conditions. Operating parameters were optimized through a feedback-capable SCADA system configured for the SX bench scale plant. These conditions were met and exceeded. TREE grades approaching 90% were produced while our Techno-Economic Assessment indicated highly favorable economic returns. The project led to the design of a pilot facility for producing roughly 500 kg/TREE/year. That plant is now in the procurement stage with constructed expected to begin in late 2020.

01 COAL, LIGNITE, AND PEAT↗

DOE OSTI2020

Evaluation of the Change in Uranium Mobility in Sediments from the Hanford 300-FF-5 Stage B Polyphosphate Field Injection

The purpose of this study was to evaluate the change in uranium mobility in the periodically re-wetted zone (PRZ) and upper unconfined aquifer of the Hanford Site’s 300-FF-5 operable unit as a result of Stage B polyphosphate (PO 4 ) injections. These 300 Area sediments are beneath or near the former North Process Pond, which has previously been shown to contain metatorbernite [Cu(UO 2 ) 2 (PO 4 ) 2 •8H 2 O] and uranophane [Ca(UO 2 ) 2 (SiO 3 OH) 2 •5H 2 O], along with aqueous and adsorbed uranium (U), and small amounts of U in calcite as a result of acidic disposal with a significant number of co-contaminants. Previous laboratory-scale studies have identified multiple mechanisms that decrease uranium mobility with polyphosphate injection: (a) precipitation of a low-solubility uranium-phosphate mineral (autunite); (b) precipitation of a Ca-phosphate solid that incorporates U; (c) precipitation of Ca-phosphate mineral (apatite group minerals) that coats existing uranium phases (i.e., U in calcite, U in Fe-oxides), reducing uranium leaching; and (d) aqueous Ca-U-carbonate species adsorption onto apatite. Given the significant amount of apatite precipitation, other U phases such as carbonates could also coprecipitate with apatite. To quantify differences in solubility, leachability, and phases of uranium between pre- and post-PO 4 -treated sediments, different types of analyses were conducted, including analysis of uranium in (a) a carbonate solution extraction from sediment over 1000 h (41.67 days), (b) six sequential liquid extractions from sediment over approximately 1 week, (c) leaching of uranium from sediments in one dimensional (1-D) column experiments over 2 months, and (d) solid phase characterization of select sediments. An additional extraction and solid phase measurements were conducted to evaluate phosphate precipitate formation. Metals were also analyzed in sequential liquid extractions as indicators of (a) amendment injection delivery, (b) co-contaminant movement, and (c) changes in solid phases. Aqueous and solid phase carbonate measurements were also conducted to evaluate changes in carbonates.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2020

Recovery of Rare Earth Elements (REEs) from Coal Mine Drainage, Phase 2

01 COAL, LIGNITE, AND PEAT↗

DOE OSTI2020

Coupled Hydrothermal Extraction and Ligand-Associated Swellable Glass Media Recovery of Rare Earth Elements from Coal Fly Ash (Final Report)

Wayne State University (WSU) researchers, in collaboration with the University of California-Los Angeles (UCLA) and Los Alamos National Laboratory (LANL), have successfully developed a new sorbent media used in a process that concentrated the rare earth content in a coal fly ash sample from southeast MI by >350×, resulting in >13 wt% REO powder. The project developed a new DTPA-associated media that was used to concentrate total REEs. This project demonstrated a coupled hydrothermal extraction and solid-liquid recovery process that produced REO powder from raw fly ash while nearly eliminating the use of organic solvents. The project successfully: 1) identified a commercially viable ash supply with >$2.5 M in REO value being deposited monthly, 2) hydrothermally extracted >77% of REEs in coal fly ash (20% more than acid alone), 3) developed a new sorbent media that was used to concentrate REEs, 4) and engineered a process that resulted in a >13 wt% REO powder. The media also demonstrates a selectivity for mid and heavy REEs over Ce and La and the potential for use in separating individual rare earth elements. An invention disclosure for the sorbent media has been filed with WSU and a patent application will be submitted in the near future. The project examined the potential to couple hydrothermal leaching of coal fly ash with the engineering of a custom ligand-associated media to provide an organic solvent-free method of extracting and recovering REEs. Fly ash feedstock was collected from Detroit area coal-fired power plants, characterized for REE content, and subjected to a bench-top batch hydrothermal leaching/dissolution process inside custom-build pressure reactors at Los Alamos National Laboratory (LANL). This process applied a dissolution technique previously developed to process spent nuclear fuel and other nuclear materials. The modified ash was acidified and the resulting leachate was enriched with REEs along with Ca, Al, and Si. Ligands known to be effective in lanthanide/actinide separation were evaluated based on a series of criteria such as selectivity and association to organosilica through hydrophobicity. Batch experiments were conducted to establish the best conditions (e.g., pH, eluent, etc.) and best ligand systems for the effective extraction of REEs from the alkaline feed solution obtained from the hydrothermal leaching process. Once the organosilica-ligand extraction media was developed for REE concentration, an acidic solution was used to back extract and concentrate the REEs into a heavily REE-laden strip solution. The REEs in the strip solution were precipitated with oxalate to produce rare earth oxides.

01 COAL, LIGNITE, AND PEAT↗

DOE OSTI2020

Engineering scale molten salt corrosion and chemistry code development

A new engineering scale transport code Mole is described. Mole was developed using the Multiphysics Object-Oriented Simulation Environment (MOOSE) framework for solving species transport problems in flowing liquid. It is applied to leaching of Cr from alloys into molten salts part a of a multi-physics, multi-scale approach for coupling chemistry with mechanical behavior modeling. Demonstrations of the leaching phenomenon were benchmarked to experimental data provided by the Molten Salt Reactor campaign and the results are presented.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2020

Destructive PIE and Safety Testing of Six AGR-2 UO 2 Capsule 3 Compacts

The Advanced Gas Reactor (AGR) Fuel Development and Qualification Program’s second irradiation experiment (AGR-2) was irradiated in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) from June 2010 to October 2013 (Collin 2014). The fuel compacts in this experiment held either tristructural isotropic (TRISO)-coated spherical kernels of uranium oxide (UO2) or TRISO-coated kernels containing both uranium carbide and uranium oxide phases (UCO). There were six separately monitored and controlled capsules in the AGR-2 test train. Capsule 3 held twelve compacts containing UO2-TRISO particles fabricated by BWX Technologies Nuclear Operations Group. The AGR-2 TRISO particles were fabricated in a pilot-scale fluidized-bed chemical vapor deposition (FB-CVD) furnace with a coating chamber inner diameter of 150 mm (Phillips, Barnes, and Hunn 2010), which was a change from the first irradiation experiment (AGR-1) particles that had been coated in a lab-scale FB-CVD coating system with a chamber inner diameter of 50 mm (Lowden 2006). The TRISO particles were overcoated with resinated graphite flake at Oak Ridge National Laboratory (ORNL), and the overcoated particles were pressed into one-inch-long, half-inch-diameter cylinders (Hunn, Montgomery, and Pappano 2010). Each cylindrical compact held an average of 1,543 TRISO particles with 9.6% enriched UO2 kernels that had a nominal diameter of 500 μm (Hunn, Savage, and Silva 2012). Capsule 3 compacts were irradiated to average calculated burnups of 9.01–10.69% fissions per initial metal atom (FIMA), and the average calculated fluences of fast neutrons with energies E n > 0.18 MeV were 3.05–3.53×10 25 n/m 2 (Sterbentz 2014). The calculated time-average, volume-average Capsule 3 compact temperatures were 996–1,062°C. However, Capsule 3 compact temperatures varied several hundred degrees across each compact, and the timeaverage minimum (TA min ) and time-average maximum (TA max ) temperatures were between 889–999°C and 1,072–1,105°C, respectively (Hawkes 2014). After irradiation, the AGR-2 test train was transferred from ATR to the INL Materials and Fuels Complex for inspection and disassembly (Ploger, Demkowicz, and Harp 2015). The initial inspection included dimensional metrology of the compacts and graphite fuel holders. Like all the AGR-2 compacts, the compacts in Capsule 3 shrank slightly during irradiation, as expected, with an average length reduction of 1.07–1.24% and an average diameter reduction of 0.13–0.41%. Post-irradiation examination (PIE) of the capsule components was completed to measure select fission products ( 90 Sr, 110m Ag, 134 Cs, 137 Cs, 144 Ce, and 154 Eu) outside the compacts (Stempien and Demkowicz 2020). This involved gamma counting of the graphite and graphoil spacers at the top and bottom of each capsule, acid leaching for radiochemical analysis of fission products on the metallic capsule components, and burn-leach analysis of the graphite holders. The total amount of 110mAg measured on the Capsule 3 components was 13% of the calculated capsule inventory. This was significantly lower than the amount of 110m Ag measured on the three UCO capsule components, which ranged from 32–70%. The lower 110m Ag release in Capsule 3 was likely due to lower peak temperatures compared with the UCO fuel capsules (Hawkes 2014). Measured inventories of the other select fission products were also lower in Capsule 3.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2020

Recovery of Rare Earth Elements from Bioleachates by Precipitation

Rare earth elements are essential components in electronic devices, however because of the limited imports and mining capabilities in the US, recycling these rare earths is crucial. Common practices used to recover REEs including hydrometallurgy and pyrometallurgy are harmful to the environment. Bioleaching, a form of biohydrometallurgy, is an emerging process that uses organic acids synthesized by microorganisms and can leach REEs at comparable efficiencies to less environmentally conscious processes. Once the REEs are leached by the bio-lixiviant produced by microorganisms, the REEs are suspended in the solution and need to precipitate out in order to be harvested for reuse. Common chemicals used for rare earth precipitation in hydrometallurgy processes include sodium sulfate and oxalic acid. These two reagents were tested at varying stoichiometric excess concentrations in bio-leachate derived from smart phone speaker magnets and bio-lixiviant. Following the precipitation reactions, it was observed that the oxalic acid reaction precipitated an abundance of iron (II) oxalate, an REE contaminate. This is most likely due to the bio-leachate having a higher pH compared to the hydrometallurgical leachates. Therefore, it was determined that sodium sulfate is a better candidate for REE precipitation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Iodine Waste Form Corrosion: PNNL Summary Testing Report

A test method to correlate the laboratory corrosion behavior of iodine-containing waste forms (IWFs) to a conceptual long-term corrosion models is required. Several candidate methods have been evaluated previously, and each method presents unique challenges and limitations. Dynamic leach tests have emerged as the preferred candidate test method to evaluate IWFs and parameterize an eventual long-term corrosion model. This report was prepared in support of this effort to define the test suite to evaluate the corrosion of IWFs, with the goal of defining and parameterizing a conceptual long-term corrosion model. A review was presented highlighting the high degree of variability between the IWF corrosion data that is available in the literature and the need for a standardized test suite. The targeted test suite is composed of a single interval screening test, a dynamic leach test, and post-test solid characterization of the monolithic IWF samples. The data presented serves two purposes: to expand the range of IWFs evaluated with the test suite to assess method variability and to further understand the corrosion of IWFs to best inform conceptual long-term corrosion model development. A series of IWF types were included in the testing, including hot isostatically pressed Ag-mordenite, silver functionalized silica-based aerogels, iodosodalites (hot isostatic pressing, sintered, glass bonded ceramic), iodoapatite, tellurite glass and glass composite materials.

42 ENGINEERING↗

DOE OSTI2021

Intermetallic PtCo Catalysts with Enhanced Performance and Stability [Slides]

Pt-based catalysts need systematic modifications to be adapted to different applications (LDV or HDV). L1 0 -CoPt particles have been demonstrated as highly active and durable cathode materials for fuel cells. Colloidal synthesis can generate catalysts with highly uniform particles size but the removal of surfactants is challenging. Acid leaching warrants a Pt shell with certain thickness, which mitigates the Co leaching. Controlling the size of L1 0 -CoPt particles is a robust method to alter their catalytic behaviours and tailor the function of catalysts. Modifying the carbon features (e.g. porosity and graphitization) is an effective method to regulate the performance and stability of catalysts to adapt the catalysts to different applications.

30 DIRECT ENERGY CONVERSION↗