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All sources NASA NTRS DOE OSTI

DOE OSTI2023

Acid-resistant catalyst supports and catalysts

A process for preparing a catalyst comprises coating substantial internal surfaces of porous inorganic powders with titanium oxide to form titanium oxide-coated inorganic powders. After the coating, an extrudate comprising the titanium oxide-coated inorganic powders is formed and calcined to form a catalyst support. Then, the catalyst support is impregnated with a solution containing one or more salts of metal selected from the group consisting of molybdenum, cobalt, and nickel.

Schmidt, Stephen R.↗

DOE OSTI2022

Solutal-buoyancy-driven intertwining and rotation of patterned elastic sheets

Abstract The intertwining of strands into 3D spirals is ubiquitous in biology, enabling functions from information storage to maintenance of cell structure and directed locomotion. In synthetic systems, entwined fibers can provide superior mechanical properties and act as artificial muscle or structural reinforcements. Unlike structures in nature, the entwinement of synthetic materials typically requires application of an external stimulus, such as mechanical actuation, light, or a magnetic field. Herein, we use computational modeling to design microscale sheets that mimic biology by transducing chemical energy into mechanical action, and thereby self-organize and interlink into 3D spirals, which spontaneously rotate. These flexible sheets are immersed in a fluid-filled microchamber that encompasses an immobilized patch of catalysts on the bottom wall. The sheets themselves can be passive or active (coated with catalyst). Catalytic reactions in the solution generate products that occupy different volumes than the reactants. The resulting density variations exert a force on the fluid (solutal buoyancy force) that causes motion, which in turn drives the interlinking and collective swirling of the sheets. The individual sheets do not rotate; rotation only occurs when the sheets are interlinked. This level of autonomous, coordinated 3D structural organization, intertwining, and rotation is unexpected in synthetic materials systems operating without external controls. Using physical arguments, we identify dimensionless ratios that are useful in scaling these ideas to other systems. These findings are valuable for creating materials that act as “machines”, and directing soft matter to undergo self-sustained, multistep assembly that is governed by intrinsic chemical reactions.

Manna, Raj Kumar (ORCID:0000000322729487)↗

DOE OSTI2022

Precision surface modification of solid oxide fuel cells via layer-by-layer surface sol–gel deposition

While solid oxide fuel cells (SOFCs) are a promising technology for a clean and sustainable future, their commercialization is hindered by limited durability and performance. Here, we report our findings on the application of a layer-by-layer surface sol–gel (SSG) coating of catalysts to dramatically enhance the electro-catalytic activity and durability of SOFC cathodes. The SSG process is capable of penetrating and preserving complex backbone microstructures of porous electrodes, creating highly conformal coatings of controlled morphology, while tailoring the composition of the surface to improve catalytic properties and durability. For example, the application of an SSG coating of PrO x to a La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3–δ (LSCF) cathode has reduced the polarization resistance from 1.136 to 0.117 Ω cm 2 at 600 °C and the degradation rate from 1.13 × 10 –3 to 2.67 × 10 –4 Ω cm 2 h –1 at 650 °C. In addition, a continuous improvement in electrode performance is demonstrated as the thickness of the coating is increased, corresponding to the linear addition of catalyst. Furthermore, this first application of the SSG technique to SOFC systems opens the door for the controlled surface modification of porous components in electrochemical systems.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

NASA NTRS2012

Highly Stable and Active Catalyst for Sabatier Reactions

Highly active Ru/TiO2 catalysts for Sabatier reaction have been developed. The catalysts have shown to be stable under repeated shutting down/startup conditions. When the Ru/TiO2 catalyst is coated on the engineered substrate Fe-CrAlY felt, activity enhancement is more than doubled when compared with an identically prepared engineered catalyst made from commercial Degussa catalyst. Also, bimetallic Ru-Rh/TiO2 catalysts show high activity at high throughput.

Hu, Jianli↗

DOE OSTI2025

Intensified atomic utilization efficiency of single-atom catalysts for nitrate conversion via electrified nanoporous membrane

Conventional electrochemical reactors for nitrate reduction typically suffer from limited reaction efficiency when applied for real-world water treatment due to poor utilization of electrocatalytic active sites. Here, we applied nanoporous electrofiltration to intensify atomic utilization by incorporating single-atom catalysts into an electrified membrane for reducing low-concentration nitrate to ammonia under realistic water conditions. We enhance the exposure of single atoms in nanopores by coating the catalysts on a carbon nanotube–interwoven membrane framework. Electrofiltration intensifies the transport and adsorption of nitrate in confined nanopores with highly exposed single-atom active sites to enhance reduction. The membrane enables a superior ammonia turnover frequency of 15.1 grams of nitrogen per gram of metal per hour, up to four orders of magnitude higher than that reported in the literature, under both high removal efficiency and Faradaic efficiency of over 86% when treating influents with a low nitrate concentration of 100 milligrams of nitrogen per liter in a residence time on the order of seconds.

Science & Technology - Other Topics↗

NASA NTRS2005

From Rockets to Racecars

NASA s Langley Research Center scientists developed a family of catalysts for low- temperature oxidation of carbon monoxide and other gases. The catalysts provide oxidation of both carbon monoxide and formaldehyde at room temperature without requiring any energy input, just a suitable flow of gas through them. Originally designed as part of an atmospheric satellite project, where the catalysts were intended to recycle and recapture carbon dioxide to enhance the operational life of carbon dioxide lasers, the entire system was made to be rugged, long-lived, and fail-safe. The low-temperature oxidation catalysts can be produced and coated onto various catalyst supports, including porous ceramic monoliths and beads, which means that they can be integrated into existing designs, made to fit in limited space, and fashioned into a variety of geometrically different products. Although the satellite project was never launched, the resulting catalysts are doing great things here on Earth, with current applications in the high-speed motor sports arena as air purifiers, so professional racecar drivers do not get carbon monoxide poisoning. Future benefits may extend even further.

Source record↗

DOE OSTI2023

Fuel cell cathode and fuel cell system including a polymeric additive

A cathode configured for use within a fuel cell system is provided. The cathode includes a cathode substrate. The cathode further includes a coating disposed upon the cathode substrate and including a fluorocarbon polymer additive configured for sintering at a temperature of less than 200° C. The fluorocarbon polymer additive may be mixed with a catalyst ink coating or may be applied separately as a topcoat layer.

Ramaswamy, Nagappan↗

DOE OSTI2020

Novel platinum group metal-free catalyst ink deposition system for combinatorial polymer electrolyte fuel cell performance evaluation

Here, a new system for rapid and precise fabrication of polymer electrolyte fuel cell (PEFC) membrane-electrode assemblies (MEAs) is introduced to facilitate rapid testing and characterization of platinum group metal-free (PGM-free) catalysts, with minimal waste of materials, using commercial combinatorial hardware and multi-channel potentiostat. The commercial combinatorial system, designed for high-throughput catalyst activity evaluation (i.e., low overpotential and current densities) using gas-diffusion electrodes (GDEs), has been further developed to enable simultaneous evaluation of the high current density performance on air of twenty-five cathodes prepared by coating catalyst-ionomer inks directly onto the membrane using a newly-developed deposition system. A nanopipette or micropipette coupled to a precise peristaltic pump is being used for precise and even catalyst ink deposition onto the membrane in each of twenty-five circular electrodes with areas of <1 cm 2 and in the precise locations required by the commercial combinatorial MEA hardware. The automated ink deposition system is coupled with a custom-designed heated vacuum table mounted on a computer-controlled XY stage to prevent deformation of the membrane and electrode layers during ink deposition onto the membrane. This system was utilized to evaluate the impact of ionomer to catalyst ratio on the hydrogen-air fuel cell performance of the PGM-free catalyst.

25 ENERGY STORAGE↗

DOE OSTI2023

HydroGEN: Low Temperature Electrolysis

In low temperature electrolysis (LTE), it is imperative to both enhance and explore durability and demonstrate the opportunities for anion exchange membrane-based water electrolysis (AEMWE). The advantage of alkaline-based systems is primarily reduced capital cost: high pH enabling platinum group metal (PGM)-free catalysts and coatings, and the enhanced stability of those components compared to proton exchange membrane (PEM) -based systems. Compared to the water-only fed AEMWE in previous LTE 2.0 work, supporting electrolytes can allow for a significant improvement in performance through higher site-access and stability by reducing utilization and overpotential stresses that lead to catalyst layer delamination.

HYDROGEN↗

DOE OSTI2024

HydroGEN: Low Temperature Electrolysis

HYDROGEN↗

DOE OSTI2021

An improved oxygen reduction reaction activity and CO 2 -tolerance of La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ achieved by a surface modification with barium cobaltite coatings

Solid oxide fuel cells (SOFCs) cathode often suffers from the poisoning effect of the contaminants commonly encountered in air such as CO 2 . Here we report an effective approach to enhancing the activity and CO 2 tolerance of the state-of-the-art La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF) cathode enabled by a coating of BaCoO 3-δ (BCO), as verified by the electrochemical testings, Raman analyses, and density functional theory calculations. When surface modified with a thin-film BCO coating, LSCF displays a much enhanced ORR activity and an improved durability against CO 2 . For example, anode supported SOFCs with the LSCF cathode coated with BCO coatings show a remarkable peak power density (Pmax) of 0.41 Wcm -2 and a significantly reduced degradation rate in current density of ~0.08% h -1 at 0.8 V and 700 °C for a period of 300 hs when humidified H2 (with 3 vol%H2O) was used as fuel and air with 8 vol% CO 2 as oxidant. The demonstrated performance is improved when compared with those of the cells with a blank LSCF electrode (a Pmax of ~0.36 Wcm -2 and a degradation rate of ~0.15% h -1 ) under the same conditions. Furthermore, the adsorption energy calculations suggests that BCO coating makes CO 2 adsorption much weaker than LSCF (-0.54 eV versus -1.07 eV).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2023

Crack detection in fuel cell electrodes using a spatial filtering technique for overcoming noisy backgrounds

Image processing is a powerful tool that allows for rapid and automated data parsing in settings that occupy large variable spaces and require large data sets. Feature detection on difficultly discerned backgrounds is a subset of image processing that facilitates the extraction of quantitative metrics from otherwise subjective data. Crack detection and quantification is an important capability in polymer electrolyte membrane fuel cell quality control, failure analysis, and optimization. This work presents a technique to perform crack detection and quantification which overcomes challenges faced by commonly used image segmentation techniques. We demonstrate the use of a geometrically filtered noise‐level detection technique to select a binary threshold value from which we then quantify how cracked a sample is. Furthermore, we demonstrate the accuracy of our technique using programmatically generated test images of known crack amounts and their performance on real‐world fuel cell catalyst layer samples.

30 DIRECT ENERGY CONVERSION↗

DOE OSTI2023

Advances in benchmarking and round robin testing for PEM water electrolysis: Reference protocol and hardware

While the number of publications in the PEM water electrolysis community increases each year, no common ground concerning reference hardware (test cells and test bench) and testing protocols has been yet established. This would, however, be necessary for the comparability of experimental results. First attempts for such reference hardware and procedures have been made in the framework of the Task 30 Electrolysis within the Technology Collaboration Programme on Advanced Fuel Cells (AFC TCP) of the International Energy Agency (IEA). Since then, improvements of both the test hardware (test cell and components) as well as the measurement protocol were identified, and a revised methodology and key results based on a comprehensive measurement series have been obtained. A detailed protocol for testing commercial reference components with a reference laboratory test cell developed in-house by Fraunhofer ISE is presented. For evaluation of the protocol and the hardware, it was tested at three different institutions at the same time. Impedance spectroscopic and polarization data was acquired and analyzed. The obtained differences in performance were calculated to give the community an expectation window to compare own data to. Finally, the importance of a thorough temperature control and the conditioning phase are demonstrated.

08 HYDROGEN↗

DOE OSTI2024

Water Confinement on Polymer Coatings Dictates Proton–Electron Transfer on Metal-Catalyzed Hydrogenation of Nitrite

Not Available

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Chemically controlled shape-morphing of elastic sheets

Two-dimensional responsive materials that change shape into complex three-dimensional structures are valuable for creating systems ranging from wearable electronics to soft robotics. Typically, the final 3D structure is unique and predetermined through the materials’ processing. Here, we use theory and simulation to devise a distinctive approach for driving shape changes of 2D elastic sheets in fluid-filled microchambers. The sheets are coated with catalyst to generate controllable fluid flows, which transform the sheets into complex 3D shapes. A given shape can be achieved by patterning the arrangement of the catalytic domains on the sheet and introducing the appropriate reactant to initiate a specific catalytic reaction. Moreover, a single sheet that encompasses multiple catalytic domains can be transformed into a variety of 3D shapes through the addition of one or more reactants. Materials systems that morph on-demand into a variety of distinct structures can simplify manufacturing processes and broaden the utility of soft materials.

36 MATERIALS SCIENCE↗

NASA NTRS1987

Consortium for Materials Development in Space. Technical section

Several topics related to materials development in space are discussed. Physical vapor transport crystal growth, the mass spectroscopic facility, surface coatings and catalyst production by electrodeposition, mass transfer by diffusion, electrooptical organic materials, and high temperature superconductors are among the topics covered.

Source record↗

NASA NTRS1990

Consortium for materials development in space

The status of the Consortium for Materials Development in Space (CMDS) is reviewed. Individual CMDS materials projects and flight opportunities on suborbital and orbital carriers are outlined. Projects include: surface coatings and catalyst production; non-linear optical organic materials; physical properties of immiscible polymers; nuclear track detectors; powdered metal sintering; iron-carbon solidification; high-temperature superconductors; physical vapor transport crystal growth; materials preparation and longevity in hyperthermal oxygen; foam formation; measurement of the microgravity environment; and commercial management of space fluids.

Source record↗

NASA NTRS1993

Corrosion-Indicating Pigment And Probes

Proposed hydrogen-sensitive paint for metal structures changes color at onset of corrosion, involving emission of hydrogen as result of electrochemical reactions. Pigment of suitable paint includes rhodium compound RhCl(PPh3)3, known as Wilkinson's catalyst. As coating on critical parts of such structures as bridges and aircraft, paint gives early warning of corrosion, and parts thus repaired or replaced before failing catastrophically. Reveals corrosion before it becomes visible to eye. Inspection for changes in color not ordinarily necessitate removal of structure from service, and costs less than inspection by x-ray or thermal neutron radiography, ultrasonic, eddy-current, or acoustic-emission techniques.

Bar-Cohen, Yoseph↗