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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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15 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Effect of operating parameters on H 2 /CO 2 conversion to methanol over Cu-Zn oxide supported on ZrO 2 polymorph catalysts: Characterization and kinetics

Kinetic aspects of the operating parameters for the catalytic conversion of H 2 /CO 2 to methanol over two novel catalysts were evaluated to understand the effect of the polymorphic ZrO 2 phase composed of Cu 0/+ -ZnO sites at the atomic level and its impact on the reaction mechanism. The catalysts were characterized by in situ and ex-situ XRD, N 2 adsorption/desorption isotherms, FRX, TPR, TPD-N 2 O, in situ XANES, TPD-CO 2 , and in situ DRIFTS techniques. The influence of different reaction variables such as the GHSV, temperature, pressure, and H 2 /CO 2 ratio were studied using a fixed bed continuous plug flow reactor. The Cu-ZnO catalyst supported on the tetragonal zirconia polymorph exhibited the highest methanol yield due to the lower activation energy when compared to the catalyst with a greater amount of the monoclinic phase. In addition, the catalysts were reused for 8 cycles of 6 hours to evaluate their stability, which can translate into lower costs for large-scale methanol production. As a result, the estimation of the kinetic parameters over Cu-Zn oxide supported on ZrO 2 polymorphs was significant for understanding the reaction mechanism, as well as to provide a pathway for scaling-up of the process.

36 MATERIALS SCIENCE↗
NASA NTRS1992

Cu-Zn binary phase diagram and diffusion couples

The objectives of this paper are to learn: (1) what information a binary phase diagram can yield; (2) how to construct and heat treat a simple diffusion couple; (3) how to prepare a metallographic sample; (4) how to operate a metallograph; (5) how to correlate phases found in the diffusion couple with phases predicted by the phase diagram; (6) how diffusion couples held at various temperatures could be used to construct a phase diagram; (7) the relation between the thickness of an intermetallic phase layer and the diffusion time; and (8) the effect of one species of atoms diffusing faster than another species in a diffusion couple.

Mccoy, Robert A.↗
DOE OSTI2022

Catalyst design to direct high-octane gasoline fuel properties for improved engine efficiency

The paraffin-to-olefin (P/O) ratio in gasoline fuel is a critical metric affecting fuel properties and engine efficiency. In the conversion of dimethyl ether (DME) to high-octane hydrocarbons over BEA zeolite catalysts, the P/O ratio can be controlled through catalyst design. Here, we report bimetallic catalysts that balance the net hydrogenation and dehydrogenation activity during DME homologation. The Cu-Zn/BEA catalyst exhibited greater relative dehydrogenation activity attributed to higher ionic site density, resulting in a lower P/O ratio (6.6) versus the benchmark Cu/BEA (9.4). The Cu-Ni/BEA catalyst exhibited increased hydrogenation due to reduced Ni species, resulting in a higher P/O ratio (19). The product fuel properties were estimated with an efficiency merit function and compared against finished gasolines and a typical alkylate blendstock. Merit values for the hydrocarbon product from all three BEA catalysts exceeded those of the comparison fuels (0–5.3), with the product from Cu-Zn/BEA exhibiting the highest merit value (9.7).

Catalyst design↗
DOE OSTI2022

Electrical-Discharge-Machining Contamination Removal from Metal Additively Manufactured Components

The use of an electrochemical dissolution process is shown to remove the recast layer contamination from the surfaces of electrical-discharge-machining cut components, as well as the interior exposed surfaces of the structure. The solution chemistry, cell potential, and exposure time are all relevant interdependent variables. Optimization of the electrode geometry should be made for each type of component. For the case of Cu-Zn recast contamination of 300-series alloy components, surface composition analysis indicates that complete electrochemical dissolution is achieved using a dilute solution of nitric acid (HNO 3 ). For example, electrochemical dissolution of the Cu-Zn recast is accomplished at 1.2 V cell potential using a 20% nitric solution and an exposure time of 4 h. The use of a nitric acid bath was specifically chosen since it’s chemically compatible and will not degrade the host alloy or the component. In sum, an electrochemically driven dissolution process can be tailored to remove of the recast contamination without affecting the integrity of the host component structure and its dimensional tolerances.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Electrochemically Dealloyed 3D Porous Copper Nanostructure as Anode Current Collector of Li-Metal Batteries

The commercialization of high-energy Li-metal batteries is impeded by Li dendrites formed during electrochemical cycling and the safety hazards it causes. Here, a novel porous copper current collector that can effectively mitigate the dendritic growth of Li is reported. This porous Cu foil is fabricated via a simple two-step electrochemical process, where Cu-Zn alloy is electrodeposited on commercial copper foil and then Zn is electrochemically dissolved to form a 3D porous structure of Cu. The 3D porous Cu layers on average have a thickness of ≈14 um and porosity of ≈72%. This current collector can effectively suppress Li dendrites in cells cycled with a high areal capacity of 10 mAh cm -2 and under a high current density of 10 mA cm -2 . This electrochemical fabrication method is facile and scalable for mass production. In conclusion, results of advanced in situ synchrotron X-ray diffraction reveal the phase evolution of the electrochemical deposition and dealloying processes.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Thermoelectric performance in disordered Cu 2 ZnSnSe 4 nanostructures driven by ultra-low thermal conductivity

Here, high-energy reactive mechanical alloying (ball milling) was used to synthesize tetragonal and cubic polymorphs of Cu 2 ZnSnSe 4 . The ordered tetragonal (I-4) polymorph undergoes a phase transition above 400 K into a Cu-Zn disordered tetragonal (I-42 m) polymorph, while the cubic (F-43 m) polymorph with full cation disorder is stabilized at room temperature. Both polymorphs show ultra-low thermal conductivities, 0.42 W m -1 K -1 at 722 K and 0.21 W m -1 K -1 at 523 K for the disordered tetragonal and cubic phases respectively. The cubic polymorph has a higher zT in the low-temperature range, peaking at 0.26 (523 K), while the disordered tetragonal has a maximum zT of 0.46 at 712 K. The latter is the highest reported zT for stoichiometric Cu 2 ZnSnSe 4 , comparable to the best-performing doped materials in the literature. A combination of experimental results and ab-initio calculations point to a coupling between structural disorder and microstructure as the mechanism behind the reported performance.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Operando high-pressure investigation of size-controlled CuZn catalysts for the methanol synthesis reaction

Although Cu/ZnO-based catalysts have been long used for the hydrogenation of CO 2 to methanol, open questions still remain regarding the role and the dynamic nature of the active sites formed at the metal-oxide interface. Here, we apply high-pressure operando spectroscopy methods to well-defined Cu and Cu 0.7 Zn 0.3 nanoparticles supported on ZnO/Al2O 3 , γ-Al 2 O 3 and SiO 2 to correlate their structure, composition and catalytic performance. We obtain similar activity and methanol selectivity for Cu/ZnO/Al 2 O 3 and CuZn/SiO 2 , but the methanol yield decreases with time on stream for the latter sample. Operando X-ray absorption spectroscopy data reveal the formation of reduced Zn species coexisting with ZnO on CuZn/SiO 2 . Near-ambient pressure X-ray photoelectron spectroscopy shows Zn surface segregation and the formation of a ZnO-rich shell on CuZn/SiO 2 . In this work we demonstrate the beneficial effect of Zn, even in diluted form, and highlight the influence of the oxide support and the Cu-Zn interface in the reactivity.

36 MATERIALS SCIENCE↗
NASA NTRS1982

Small particles in plumes of Mount St. Helens

Particles in the size range 0.1-25 microns were sampled by aircraft carrying a quartz crystal microcascade in the Mount St. Helens plume on three dates in August and September 1980. Two of the sampling dates represented 'typical' emissions of the volcano between plinian eruptions. One sampling flight was made 1-4 hours before the small plinian eruption of August 7, 1980 when the plume had become discontinuous and visibly darker. The plume sampled on August 7, before the eruption, contained mainly approximately 2-micron diameter silicic glass particles, fragments of the Mount St. Helens magma. The typical plumes sampled on September 22 and August 6 had much smaller concentrations of particles, trimodal size distributions with peaks at 10, 0.4, and 0.1 microns. The particles were largely nonsilicate and apparently represented Cu-Zn oxide (10 micron peak), Al sulfate, chloride, and oxide, and sulfuric acid (smallest size peak).

Rose, W. I.↗
DOE OSTI2020

Materials Data on Zn3Cu by Materials Project

CuZn3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Cu is bonded to twelve equivalent Zn atoms to form CuZn12 cuboctahedra that share corners with six equivalent CuZn12 cuboctahedra, corners with twelve equivalent ZnZn8Cu4 cuboctahedra, edges with eighteen equivalent ZnZn8Cu4 cuboctahedra, faces with eight equivalent CuZn12 cuboctahedra, and faces with twelve equivalent ZnZn8Cu4 cuboctahedra. There are six shorter (2.65 Å) and six longer (2.71 Å) Cu–Zn bond lengths. Zn is bonded to four equivalent Cu and eight equivalent Zn atoms to form distorted ZnZn8Cu4 cuboctahedra that share corners with four equivalent CuZn12 cuboctahedra, corners with fourteen equivalent ZnZn8Cu4 cuboctahedra, edges with six equivalent CuZn12 cuboctahedra, edges with twelve equivalent ZnZn8Cu4 cuboctahedra, faces with four equivalent CuZn12 cuboctahedra, and faces with sixteen equivalent ZnZn8Cu4 cuboctahedra. There are a spread of Zn–Zn bond distances ranging from 2.67–2.75 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ZnCu by Materials Project

CuZn is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Cu is bonded in a body-centered cubic geometry to eight equivalent Zn atoms. All Cu–Zn bond lengths are 2.56 Å. Zn is bonded in a body-centered cubic geometry to eight equivalent Cu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ZnCu3 by Materials Project

Cu3Zn crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are five inequivalent Cu sites. In the first Cu site, Cu is bonded to nine Cu and three equivalent Zn atoms to form CuZn3Cu9 cuboctahedra that share corners with twelve CuZn3Cu9 cuboctahedra, edges with six equivalent ZnZn6Cu6 cuboctahedra, edges with eighteen CuZn3Cu9 cuboctahedra, faces with six equivalent ZnZn6Cu6 cuboctahedra, and faces with twelve CuZn3Cu9 cuboctahedra. There are three shorter (2.55 Å) and six longer (2.62 Å) Cu–Cu bond lengths. All Cu–Zn bond lengths are 2.60 Å. In the second Cu site, Cu is bonded to twelve Cu atoms to form CuCu12 cuboctahedra that share corners with six equivalent CuCu12 cuboctahedra, corners with six equivalent ZnZn6Cu6 cuboctahedra, edges with six equivalent ZnZn6Cu6 cuboctahedra, edges with eighteen CuZn3Cu9 cuboctahedra, and faces with eighteen CuZn3Cu9 cuboctahedra. All Cu–Cu bond lengths are 2.62 Å. In the third Cu site, Cu is bonded to nine Cu and three equivalent Zn atoms to form CuZn3Cu9 cuboctahedra that share corners with seventeen CuZn3Cu9 cuboctahedra, edges with six equivalent ZnZn6Cu6 cuboctahedra, edges with sixteen CuZn3Cu9 cuboctahedra, faces with six equivalent ZnZn6Cu6 cuboctahedra, and faces with fifteen CuZn3Cu9 cuboctahedra. There are three shorter (2.55 Å) and six longer (2.62 Å) Cu–Cu bond lengths. All Cu–Zn bond lengths are 2.60 Å. In the fourth Cu site, Cu is bonded to sixteen Cu atoms to form CuCu16 cuboctahedra that share corners with six equivalent ZnZn6Cu6 cuboctahedra, corners with sixteen CuZn3Cu9 cuboctahedra, edges with six equivalent ZnZn6Cu6 cuboctahedra, edges with eighteen CuZn3Cu9 cuboctahedra, and faces with thirty-four CuZn3Cu9 cuboctahedra. There are a spread of Cu–Cu bond distances ranging from 2.55–5.24 Å. In the fifth Cu site, Cu is bonded to nine Cu and three equivalent Zn atoms to form CuZn3Cu9 cuboctahedra that share corners with seventeen CuZn3Cu9 cuboctahedra, edges with six equivalent ZnZn6Cu6 cuboctahedra, edges with sixteen CuZn3Cu9 cuboctahedra, faces with six equivalent ZnZn6Cu6 cuboctahedra, and faces with fifteen CuZn3Cu9 cuboctahedra. All Cu–Cu bond lengths are 2.62 Å. All Cu–Zn bond lengths are 2.60 Å. Zn is bonded to six equivalent Cu and six equivalent Zn atoms to form ZnZn6Cu6 cuboctahedra that share corners with six equivalent CuCu12 cuboctahedra, corners with six equivalent ZnZn6Cu6 cuboctahedra, edges with six equivalent ZnZn6Cu6 cuboctahedra, edges with eighteen CuZn3Cu9 cuboctahedra, faces with six equivalent ZnZn6Cu6 cuboctahedra, and faces with twelve equivalent CuZn3Cu9 cuboctahedra. All Zn–Zn bond lengths are 2.62 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ZnCu2 by Materials Project

Cu2Zn is beta-derived structured and crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Cu is bonded to nine equivalent Cu and three equivalent Zn atoms to form CuZn3Cu9 cuboctahedra that share corners with three equivalent ZnZn6Cu6 cuboctahedra, corners with nine equivalent CuZn3Cu9 cuboctahedra, edges with nine equivalent ZnZn6Cu6 cuboctahedra, edges with fifteen equivalent CuZn3Cu9 cuboctahedra, faces with six equivalent ZnZn6Cu6 cuboctahedra, and faces with twelve equivalent CuZn3Cu9 cuboctahedra. There are three shorter (2.55 Å) and six longer (2.64 Å) Cu–Cu bond lengths. All Cu–Zn bond lengths are 2.60 Å. Zn is bonded to six equivalent Cu and six equivalent Zn atoms to form ZnZn6Cu6 cuboctahedra that share corners with six equivalent CuZn3Cu9 cuboctahedra, corners with six equivalent ZnZn6Cu6 cuboctahedra, edges with six equivalent ZnZn6Cu6 cuboctahedra, edges with eighteen equivalent CuZn3Cu9 cuboctahedra, faces with six equivalent ZnZn6Cu6 cuboctahedra, and faces with twelve equivalent CuZn3Cu9 cuboctahedra. All Zn–Zn bond lengths are 2.64 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ZnCu3 by Materials Project

Cu3Zn crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. there are two inequivalent Cu sites. In the first Cu site, Cu is bonded to twelve Cu atoms to form CuCu12 cuboctahedra that share corners with six equivalent CuCu12 cuboctahedra, corners with twelve equivalent ZnZn6Cu6 cuboctahedra, edges with eighteen CuCu12 cuboctahedra, faces with two equivalent ZnZn6Cu6 cuboctahedra, and faces with eighteen CuCu12 cuboctahedra. There are six shorter (2.55 Å) and six longer (2.61 Å) Cu–Cu bond lengths. In the second Cu site, Cu is bonded to nine Cu and three equivalent Zn atoms to form CuZn3Cu9 cuboctahedra that share corners with eighteen equivalent CuZn3Cu9 cuboctahedra, edges with six equivalent ZnZn6Cu6 cuboctahedra, edges with twelve CuCu12 cuboctahedra, faces with six equivalent ZnZn6Cu6 cuboctahedra, and faces with fourteen CuCu12 cuboctahedra. All Cu–Cu bond lengths are 2.61 Å. All Cu–Zn bond lengths are 2.61 Å. Zn is bonded to six equivalent Cu and six equivalent Zn atoms to form ZnZn6Cu6 cuboctahedra that share corners with six equivalent ZnZn6Cu6 cuboctahedra, corners with twelve equivalent CuCu12 cuboctahedra, edges with six equivalent ZnZn6Cu6 cuboctahedra, edges with twelve equivalent CuZn3Cu9 cuboctahedra, faces with six equivalent ZnZn6Cu6 cuboctahedra, and faces with fourteen CuCu12 cuboctahedra. All Zn–Zn bond lengths are 2.61 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ZnCu by Materials Project

CuZn crystallizes in the orthorhombic Cmmm space group. The structure is two-dimensional and consists of two CuZn sheets oriented in the (0, 1, 0) direction. Cu is bonded in a 8-coordinate geometry to four equivalent Zn atoms. All Cu–Zn bond lengths are 2.55 Å. Zn is bonded in a 8-coordinate geometry to four equivalent Cu atoms.

36 MATERIALS SCIENCE↗