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DOE OSTI2023

Interplay between copper redox and transfer and support acidity and topology in low temperature NH 3 -SCR

Low-temperature standard NH 3 -SCR over copper-exchanged zeolite catalysts occurs on NH 3 -solvated Cu-ion active sites in a quasi-homogeneous manner. As key kinetically relevant reaction steps, the reaction intermediate Cu II (NH 3 ) 4 ion hydrolyzes to Cu II (OH)(NH 3 ) 3 ion to gain redox activity. The Cu II (OH)(NH 3 ) 3 ion also transfers between neighboring zeolite cages to form highly reactive reaction intermediates. Via operando electron paramagnetic resonance spectroscopy and SCR kinetic measurements and density functional theory calculations, we demonstrate here that such kinetically relevant steps become energetically more difficult with lower support Brønsted acid strength and density. Consequently, Cu/LTA displays lower Cu atomic efficiency than Cu/CHA and Cu/AEI, which can also be rationalized by considering differences in their support topology. By carrying out hydrothermal aging to eliminate support Brønsted acid sites, both Cu II (NH 3 ) 4 ion hydrolysis and Cu II (OH)(NH 3 ) 3 ion migration are hindered, leading to a marked decrease in Cu atomic efficiency for all catalysts.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Investigating Cu-Site Doped Cu–Sb–S Nanoparticles Using Photoelectron and Electron Paramagnetic Resonance Spectroscopy

Tetrahedrite (Cu 12 Sb 4 S 13 ) and famatinite (Cu 3 SbS 4 ) are good candidates for green energy applications because they possess promising thermoelectric and photovoltaic properties as well as contain earth-abundant and nontoxic constituents. Herein, X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and electron paramagnetic resonance spectroscopy (EPR) methods examined inherent electronic properties and interatomic magnetic interactions of Cu-site doped tetrahedrite and famatinite nanomaterials. An energy-efficient modified polyol method was utilized for the synthesis of tetrahedrite and famatinite nanoparticles doped on the Cu-site with Zn, Fe, Ni, Mn, and Co. This is the first parallel study of tetrahedrite and famatinite nanomaterials with XPS, UPS, and EPR methods alongside a systematic analysis of dopant-dependent effects on the electronic structure and magnetic interactions for each material. XPS showed that the Cu and Sb species in tetrahedrite and famatinite possess different oxidation states, while UPS characterization reveals larger dopant-dependent shifts in the work function for tetrahedrite nanoparticles (4.21 to 4.79 eV) than for famatinite nanoparticles (4.57 to 4.77 eV). Finally, all famatinite nanoparticles display an EPR signal, indicating trace amounts of paramagnetic Cu(II) present below the detection limit of XPS. For tetrahedrite, EPR signatures were observed only for the Zn-doped and Mn-doped nanoparticles, suggesting signal broadening from Cu–Cu spin exchange or spin–lattice relaxation. This study demonstrates the complementary nature of XPS and EPR techniques for studying the oxidation states of metals in solid-state nanomaterials. Comparing the electronic and magnetic properties of tetrahedrite and famatinite while studying the impact of dopant incorporation will guide future endeavors in designing sustainable, high-performance materials for renewable energy applications.

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

Ag Alloying in Cu 2– y Ag y Ba(Ge,Sn)Se 4 Films and Photovoltaic Devices

Trigonal Cu 2 BaGe 1–x Sn x Se 4 (CBGTSe) has recently gained interest as a potential photovoltaic absorber to target mitigation of antisite defect formation in Cu 2 ZnSn(S,Se) 4 . This study examines partial substitution of Cu by Ag as a potential approach to tune the properties of Ag-incorporated CBGTSe in the following aspects: 1) phase stability and crystal structure as a function of Ag content; 2) film morphology and grain structure; 3) charge carrier properties; 4) band positions; and 5) charge carrier kinetics and recombination. Up to 20% of Cu can be substituted by Ag in CBGTSe, while above 20% a phase mixture appears. Increasing Ag content induces larger average grain size and reduced hole carrier densities. In contrast, photoelectron spectroscopy and photoluminescence measurements reveal negligible impact of Ag substitution on ionization potential (≈5.4 eV) and electron affinity (≈3.7 eV). Also, Ag content offers negligible impact on carrier lifetimes (few ns). Consistent with these fundamental properties, solar cells based on two different Ag/(Ag + Cu) ratios (≈0% and ≈20%) show comparable power conversion efficiencies (≈2.7–2.8%). Finally, these results indicate that CBGTSe films and solar cells may be less sensitive to Ag substitution compared to Cu 2 ZnSn(S,Se) 4 , at least at the current level of absorber and device optimization.

14 SOLAR ENERGY↗
DOE OSTI2020

Highly Selective Electrocatalytic Reduction of CO 2 into Methane on Cu–Bi Nanoalloys

Methane (CH 4 ), the main component of natural gas, is one of the most valuable products facilitating energy storage via electricity conversion. However, the poor selectivity and high overpotential for CH 4 formation with metallic Cu catalysts prevent realistic applications. Introducing a second element to tune the electronic state of Cu has been widely used as an effective method to improve catalytic performance, but achieving high selectivity and activity toward CH 4 remains challenging. Here, we successfully synthesized Cu–Bi NPs, which exhibit a CH 4 Faradaic efficiency (FE) as high as 70.6% at -1.2 V versus reversible hydrogen electrode (RHE). The FE of Cu–Bi NPs has increased by approximately 25-fold compared with that of Cu NPs. DFT calculations showed that alloying Cu with Bi significantly decreases the formation energy of *COH formation, the rate-determining step, which explains the improved performance. Further analysis showed that Cu that has been partially oxidized because of electron withdrawal by Bi is the most possible active site.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Slow spin dynamics in the hyperhoneycomb lattice [ ( C 2 H 5 ) 3 NH ] 2 Cu 2 ( C 2 O 4 ) 3 revealed by H 1 NMR studies

We report the results of magnetic susceptibility χ and H 1 nuclear magnetic resonance (NMR) measurements on a three-dimensional hyperhoneycomb lattice compound [ ( C 2 H 5 ) 3 NH ] 2 Cu 2 ( C 2 O 4 ) 3 (CCCO). The average value of the antiferromagnetic (AFM) exchange coupling between the Cu 2 + ( S = 1 / 2 ) spins was determined to be J ~ 50 K from the χ measurements. No long-range magnetic ordering has been observed down to T = 50 mK, although NMR lines become slightly broader at low temperatures below 1 K. The broadening of the NMR spectrum observed below 1 K reveals that the Cu spin moments remain at this temperature, suggesting a non-spin-singlet ground state. The temperature and magnetic field dependence of 1 / T 1 at temperatures above 20 K is well explained by paramagnetic thermal spin fluctuations where the fluctuation frequency of Cu 2 + spins is higher than the NMR frequency of the order of megahertz. However, a clear signature of the slowing down of the Cu 2 + spin fluctuations was observed at low temperatures where 1 / T 1 shows a thermally activated behavior. The magnetic field dependence of the magnitude of the spin excitation gap suggests that the magnetic behaviors of CCCO are characterized as an AFM chain at low temperatures.

1-dimensional systems↗
DOE OSTI2020

Materials Data on Zn35Cu17 by Materials Project

Cu17Zn35 is gamma-brass-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are seventeen inequivalent Cu sites. In the first Cu site, Cu is bonded in a 4-coordinate geometry to three Cu and ten Zn atoms. There are a spread of Cu–Cu bond distances ranging from 2.55–2.73 Å. There are a spread of Cu–Zn bond distances ranging from 2.54–2.85 Å. In the second Cu site, Cu is bonded in a 4-coordinate geometry to three Cu and ten Zn atoms. There are a spread of Cu–Cu bond distances ranging from 2.55–2.73 Å. There are a spread of Cu–Zn bond distances ranging from 2.53–2.86 Å. In the third Cu site, Cu is bonded in a 4-coordinate geometry to three Cu and ten Zn atoms. There are a spread of Cu–Cu bond distances ranging from 2.54–2.73 Å. There are a spread of Cu–Zn bond distances ranging from 2.53–2.86 Å. In the fourth Cu site, Cu is bonded in a 5-coordinate geometry to two Cu and eleven Zn atoms. There are one shorter (2.71 Å) and one longer (2.72 Å) Cu–Cu bond lengths. There are a spread of Cu–Zn bond distances ranging from 2.52–2.89 Å. In the fifth Cu site, Cu is bonded in a 5-coordinate geometry to two Cu and eleven Zn atoms. Both Cu–Cu bond lengths are 2.72 Å. There are a spread of Cu–Zn bond distances ranging from 2.52–2.88 Å. In the sixth Cu site, Cu is bonded in a 5-coordinate geometry to two Cu and eleven Zn atoms. Both Cu–Cu bond lengths are 2.72 Å. There are a spread of Cu–Zn bond distances ranging from 2.53–2.87 Å. In the seventh Cu site, Cu is bonded in a 4-coordinate geometry to three Cu and ten Zn atoms. There are one shorter (2.72 Å) and one longer (2.73 Å) Cu–Cu bond lengths. There are a spread of Cu–Zn bond distances ranging from 2.53–2.86 Å. In the eighth Cu site, Cu is bonded in a 4-coordinate geometry to three Cu and ten Zn atoms. There are one shorter (2.72 Å) and one longer (2.73 Å) Cu–Cu bond lengths. There are a spread of Cu–Zn bond distances ranging from 2.52–2.85 Å. In the ninth Cu site, Cu is bonded in a 4-coordinate geometry to three Cu and ten Zn atoms. Both Cu–Cu bond lengths are 2.72 Å. There are a spread of Cu–Zn bond distances ranging from 2.53–2.85 Å. In the tenth Cu site, Cu is bonded in a 12-coordinate geometry to one Cu and eleven Zn atoms. There are a spread of Cu–Zn bond distances ranging from 2.54–2.74 Å. In the eleventh Cu site, Cu is bonded in a 12-coordinate geometry to two Cu and ten Zn atoms. There are a spread of Cu–Zn bond distances ranging from 2.53–2.72 Å. In the twelfth Cu site, Cu is bonded in a 12-coordinate geometry to two Cu and ten Zn atoms. There are a spread of Cu–Zn bond distances ranging from 2.53–2.72 Å. In the thirteenth Cu site, Cu is bonded in a 12-coordinate geometry to two Cu and ten Zn atoms. There are a spread of Cu–Zn bond distances ranging from 2.53–2.72 Å. In the fourteenth Cu site, Cu is bonded in a 9-coordinate geometry to three Cu and nine Zn atoms. There are a spread of Cu–Zn bond distances ranging from 2.55–2.62 Å. In the fifteenth Cu site, Cu is bonded in a 12-coordinate geometry to two Cu and ten Zn atoms. There are a spread of Cu–Zn bond distances ranging from 2.53–2.72 Å. In the sixteenth Cu site, Cu is bonded in a 9-coordinate geometry to three Cu and nine Zn atoms. There are a spread of Cu–Zn bond distances ranging from 2.55–2.62 Å. In the seventeenth Cu site, Cu is bonded in a 12-coordinate geometry to three Cu and nine Zn atoms. There are a spread of Cu–Zn bond distances ranging from 2.55–2.63 Å. There are thirty-five inequivalent Zn sites. In the first Zn site, Zn is bonded in a 12-coordinate geometry to six Cu and six Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.60–2.71 Å. In the second Zn site, Zn is bonded in a 12-coordinate geometry to six Cu and six Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.60–2.71 Å. In the third Zn site, Zn is bonded in a 12-coordinate geometry to six Cu and six Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.60–2.71 Å. In the fourth Zn site, Zn is bonded in a 12-coordinate geometry to five Cu and seven Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.63–2.75 Å. In the fifth Zn site, Zn is bonded in a 12-coordinate geometry to five Cu and seven Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.60–2.77 Å. In the sixth Zn site, Zn is bonded in a 12-coordinate geometry to five Cu and seven Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.61–2.76 Å. In the seventh Zn site, Zn is bonded in a 12-coordinate geometry to five Cu and seven Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.60–2.67 Å. In the eighth Zn site, Zn is bonded in a 12-coordinate geometry to four Cu and eight Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.62–2.70 Å. In the ninth Zn site, Zn is bonded in a 11-coordinate geometry to five Cu and six Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.57–2.68 Å. In the tenth Zn site, Zn is bonded in a 11-coordinate geometry to five Cu and six Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.57–2.68 Å. In the eleventh Zn site, Zn is bonded in a 11-coordinate geometry to six Cu and five Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.63–2.65 Å. In the twelfth Zn site, Zn is bonded in a 11-coordinate geometry to six Cu and five Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.62–2.65 Å. In the thirteenth Zn site, Zn is bonded in a 11-coordinate geometry to six Cu and five Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.63–2.65 Å. In the fourteenth Zn site, Zn is bonded in a 11-coordinate geometry to five Cu and six Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.57–2.68 Å. In the fifteenth Zn site, Zn is bonded in a 11-coordinate geometry to five Cu and six Zn atoms. There are one shorter (2.57 Å) and two longer (2.68 Å) Zn–Zn bond lengths. In the sixteenth Zn site, Zn is bonded in a 2-coordinate geometry to four Cu and seven Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.56–2.84 Å. In the seventeenth Zn site, Zn is bonded in a 11-coordinate geometry to six Cu and five Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.62–2.65 Å. In the eighteenth Zn site, Zn is bonded in a 11-coordinate geometry to five Cu and six Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.63–2.85 Å. In the nineteenth Zn site, Zn is bonded in a 11-coordinate geometry to six Cu and five Zn atoms. There are two shorter (2.63 Å) and one longer (2.64 Å) Zn–Zn bond lengths. In the twentieth Zn site, Zn is bonded in a 11-coordinate geometry to five Cu and six Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.63–2.88 Å. In the twenty-first Zn site, Zn is bonded in a 11-coordinate geometry to five Cu and six Zn atoms. There are two shorter (2.67 Å) and one longer (2.86 Å) Zn–Zn bond lengths. In the twenty-second Zn site, Zn is bonded in a 11-coordinate geometry to five Cu and six Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.65–2.87 Å. In the twenty-third Zn site, Zn is bonded in a 11-coordinate geometry to five Cu and six Zn atoms. There are one shorter (2.67 Å) and one longer (2.86 Å) Zn–Zn bond lengths. In the twenty-fourth Zn site, Zn is bonded in a 11-coordinate geometry to five Cu and six Zn atoms. There are one shorter (2.65 Å) and one longer (2.86 Å) Zn–Zn bond lengths. In the twenty-fifth Zn site, Zn is bonded in a 11-coordinate geometry to five Cu and six Zn atoms. There are one shorter (2.67 Å) and one longer (2.86 Å) Zn–Zn bond lengths. In the twenty-sixth Zn site, Zn is bonded in a 2-coordinate geometry to four Cu and seven Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.57–2.83 Å. In the twenty-seventh Zn site, Zn is bonded in a 11-coordinate geometry to five Cu and six Zn atoms. The Zn–Zn bond length is 2.87 Å. In the twenty-eighth Zn site, Zn is bonded in a 11-coordinate geometry to four Cu and seven Zn atoms. There are one shorter (2.85 Å) and one longer (2.86 Å) Zn–Zn bond lengths. In the twenty-ninth Zn site, Zn is bonded in a 11-coordinate geometry to five Cu and six Zn atoms. The Zn–Zn bond length is 2.85 Å. In the thirtieth Zn site, Zn is bonded in a 11-coordinate geometry to four Cu and seven Zn atoms. Both Zn–Zn bond lengths are 2.85 Å. In the thirty-first Zn site, Zn is bonded in a 11-coordinate geometry to five Cu and six Zn atoms. The Zn–Zn bond length is 2.86 Å. In the thirty-second Zn site, Zn is bonded in a 11-coordinate geometry to four Cu and seven Zn atoms. There are one shorter (2.84 Å) and one longer (2.85 Å) Zn–Zn bond lengths. In the thirty-third Zn site, Zn is bonded in a 1-coordinate geometry to three Cu and ten Zn atoms. In the thirty-fourth Zn site, Zn is bonded in a 1-coordinate geometry to three Cu and ten Zn atoms. In the thirty-fifth Zn site, Zn is bonded in a 1-coordinate geometry to three Cu and ten Zn atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Metal Complex Molecular Solids Showing Band-like Transport Driven by In Situ Ligand Exchange

Transition-metal complexes exhibit excellent charge transport properties in solid films, rendering them promising for application in modern electronics. Although the charge transport mechanism of metal complex solids with multiple redox states is considered to be governed by self-exchange hole hopping, the effect of additives, such as Lewis bases, has not been identified. Herein, we describe the effect of 4- tert -butylpyridine (TBP) on the charge transport mechanism and film properties of [Cu(dmbpy) 2 ] 2 + / + (dmbpy = 6,6'-dimethyl-2,2'-bipyridine)-based molecular solids. The formation of [Cu(TBP) 4 ] 2 + , excess TBP, and free dmbpy from the ligand-exchange reaction between [Cu(dmbpy) 2 ] 2 + and TBP increases the film conductivity and changes the transport mechanism from hopping to band-like transport through a combination of chemical composition, film morphology, and crystallographic changes. In conclusion, these findings advance our understanding of the fundamental properties of molecular metal complex solids and enable optoelectronic applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Spin-Glass-like State and Reversible Room-Temperature Magnetocaloric Effect in Double Distorted Perovskites Nd(Cu 3– x Mn x )Mn 4 O 12

The preparation, complex magnetic properties and room-temperature magnetocaloric effect in Nd(Cu 3–x Mn x )Mn 4 O 12 with cation distribution (Nd 3+ ) A (Cu 3–x 2+x Mn x 3+ ) A' (Mn 1+x 3+ Mn 3–x 4+ ) B O 12 2– (x = 1 and 1.5) have been reported. Both compounds show a sharp paramagnetic-ferromagnetic (FM) transition at T C of 300 and 280 K, respectively. The substitution of Cu by Mn at the A' site induces the emergence of a spin glass state below ≈63 K for x = 1 and ≈72 K for x = 1.5 compound. Another antiferromagnetic-like magnetic transition is also observed in both compounds at 23 and 28 K, respectively, which is discussed as the antiferromagnetic coupling between Nd 3+ at the A' site and (Mn 3+ /Mn 4+ ) at the B site. These two compounds exhibit room-temperature magnetocaloric effect. For a small field of 2 T, the maximum magnetic entropy changes –ΔS M are 1.5 J/kg K at 300 K and 1.4 J/kg K at 280 K, respectively. Furthermore, the –ΔS M (T) curves show an asymmetric distribution, resulting in high refrigerant capacity values for both compounds. We further demonstrate the distinct roles of the A'- and B-site spins on the magnetic properties and the origin of the spin-glass-like state in double distorted perovskites Ln(Cu 3–x Mn x )Mn 4 O 12 family of compounds.

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

A comparative study of solute trapping in Fe-(33–45 at%) Cu alloys manufactured by laser directed energy deposition

The high cooling rates in laser directed energy deposition (DED-LB) of alloys lead to substantial amounts of solute trapping as solute atoms cannot diffuse away from the solid/liquid interface before it advances. In some concentrated alloys, this results in supersaturated solid phases that form nanoscale hierarchical microstructures when the solute atoms precipitate out during reheating from subsequent laser passes. We choose the Iron-Copper (Fe-Cu) binary alloy as model system as it is chemically homogeneous in the liquid phase and has negligible solid solubility at room temperature. Two alloys with nominal compositions in atomic (at.) %, Fe67Cu33 and Fe55Cu45, were manufactured using DED-LB. Scanning transmission electron microscopy (STEM), energy dispersive spectroscopy (EDS) and wavelength dispersive spectroscopy (WDS) were used to characterize the nanostructures and heterogeneous chemical compositions. A non-equilibrium solute partitioning model was used to compute the supersaturated chemistries of the constituent phases and validated with experimentally measured compositions. The measured phase compositions of the two alloys were very similar, at roughly 12 at.% Cu and 4 at.% Fe in the α(bcc)-Fe and ε(fcc)-Cu phases respectively, despite having different processing parameters and mechanical behavior. This indicates that the total thermal history, that depends on both the processing parameters and laser scan pattern, plays a stronger role on the final microstructure evolution than just the initial quantity of trapped solute. In addition, we find that current non-equilibrium solute partitioning models applied on the continuum scale fall short of predicting accurate quantitative phase compositions in concentrated alloys, although the qualitative trends are captured correctly.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Refining Microstructures in Additively Manufactured Al/Cu Gradients Through TiB 2 Inclusions

Here, the additive manufacture of compositionally graded Al/Cu parts by laser engineered net shaping (LENS) is demonstrated. The use of a blue light build laser enabled deposition on a Cu substrate. The thermal gradient and rapid solidification inherent to selective laser melting enabled mass transport of Cu up to 4 mm from a Cu substrate through a pure Al deposition, providing a means of producing gradients with finer step sizes than the printed layer thicknesses. Divorcing gradient continuity from layer or particle size makes LENS a potentially enabling technology for the manufacture of graded density impactors for ramp compression experiments. Printing graded structures with pure Al, however, was prevented by the growth of Al 2 Cu 3 dendrites and acicular grains amid a matrix of Al 2 Cu. A combination of adding TiB 2 grain refining powder and actively varying print layer composition suppressed the dendritic growth mode and produced an equiaxed microstructure in a compositionally graded part. Material phase was characterized for crystal structure and nanoindentation hardness to enable a discussion of phase evolution in the rapidly solidifying melt pool of a LENS print.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Exploring competitive metal binding and crystallization of UO 2 2+ and Cu 2+ tetrahydrofuran-2,3,4,5-tetracarboxylic acid complexes

Solvent extractions are used to separate actinide elements from fission products in nuclear waste streams and the successful isolation of specific species utilize subtle differences in metal ligand binding. Metal ligand binding is also important in crystallization of metal organic materials and herein we explore the importance of competitive binding in the tetrahydrofuran-2,3,4,5-tetracarboxylic acid (THFTCA) system. This ligand has been previously evaluated for the selective extraction of uranium from other lanthanides and actinides and in the current research, we evaluate the crystallization of uranyl-THFTCA complexes in the presence of Cu 2+ , Sr 2+ , Th 4+ , and Ce 3+ . Three major phases were formed in the crystallization experiments and characterized with single crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, and Raman spectroscopy. Two of the resulting phases were novel (UTHF1 ((C 4 H 10 N 2 )[UO 2 (C 8 H 8 O 9 ) 2 ]∙2H 2 O) and UTHF2 (Na[(UO 2 )(C 8 H 5 O 9 )(H 2 O)]∙ 3.5 H 2 O)), whereas the third (CuTHF1) was previously reported in the literature. Raman spectroscopy was utilized to evaluate spectral changes in the mother liquor of UTHF1, UTHF2, and CuTHF1 over time to assess the crystallization process. Further, isothermal titration calorimetry was used to determine the binding constants for UO 2 2+ and Cu 2+ to the THFTCA ligand in solution and evaluate the role of competitive metal binding in this system. The thermodynamic parameters and the crystallographic data were used to justify the formation of a weaker UO 2 2+ -THFTCA complex. Formation of a weaker UO 2 2+ -THFTCA complex supports our findings that UTHF1 only forms in homomeric systems, but suggests that the crystallization of UTHF2 and CuTHF1 is reliant on the presence of additional counter ions and ligands to change the amount of available THFTCA ligand.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Scanning SQUID characterization of extremely overdoped La 2-x Sr x CuO 4

Recently, advances in film synthesis methods have enabled a study of extremely overdoped La 2 - x Sr x Cu O 4 . This has revealed a surprising behavior of the superfluid density as a function of doping and temperature, the explanation of which is vividly debated. One popular class of models posits electronic phase separation, where the superconducting phase fraction decreases with doping, while some competing phase (e.g., ferromagnetic) progressively takes over. A problem with this scenario is that all the way up to the dome edge the superconducting transition remains sharp, according to mutual inductance measurements. However, the physically relevant scale is the Pearl penetration depth Λ P , and this technique probes the sample on a length scale L that is much larger than Λ P . In the present paper, we use local scanning superconducting quantum interference device (SQUID) measurements that probe the susceptibility of the sample on the scale L << Λ P . Our SQUID maps show uniform landscapes of susceptibility and excellent overall agreement of the local penetration depth data with the bulk measurements. Overall, these results contribute an important piece to the puzzle of how high-temperature superconductivity vanishes on the overdoped side of the cuprate phase diagram.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Materials Data on Cu39S20 by Materials Project

Cu39S20 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are thirty-nine inequivalent Cu+1.03+ sites. In the first Cu+1.03+ site, Cu+1.03+ is bonded to one Cu+1.03+ and four S2- atoms to form distorted CuCuS4 tetrahedra that share corners with six CuCu2S4 tetrahedra, edges with two CuCu2S4 tetrahedra, and a faceface with one CuS6 octahedra. The Cu–Cu bond length is 2.45 Å. There are a spread of Cu–S bond distances ranging from 2.31–2.48 Å. In the second Cu+1.03+ site, Cu+1.03+ is bonded in a distorted trigonal planar geometry to three S2- atoms. There are one shorter (2.30 Å) and two longer (2.36 Å) Cu–S bond lengths. In the third Cu+1.03+ site, Cu+1.03+ is bonded to two Cu+1.03+ and four S2- atoms to form distorted CuCu2S4 tetrahedra that share a cornercorner with one CuS6 octahedra, corners with two CuCuS4 tetrahedra, and edges with five CuCu2S4 tetrahedra. The corner-sharing octahedral tilt angles are 53°. There are one shorter (2.49 Å) and one longer (2.50 Å) Cu–Cu bond lengths. There are a spread of Cu–S bond distances ranging from 2.36–2.48 Å. In the fourth Cu+1.03+ site, Cu+1.03+ is bonded in a 6-coordinate geometry to four Cu+1.03+ and six S2- atoms. There are two shorter (2.52 Å) and one longer (2.53 Å) Cu–Cu bond lengths. There are a spread of Cu–S bond distances ranging from 2.60–2.93 Å. In the fifth Cu+1.03+ site, Cu+1.03+ is bonded to two Cu+1.03+ and four S2- atoms to form distorted CuCu2S4 tetrahedra that share a cornercorner with one CuS6 octahedra, corners with three CuCuS4 tetrahedra, and edges with five CuCuS4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. The Cu–Cu bond length is 2.46 Å. There are a spread of Cu–S bond distances ranging from 2.36–2.50 Å. In the sixth Cu+1.03+ site, Cu+1.03+ is bonded to two Cu+1.03+ and four S2- atoms to form distorted CuCu2S4 tetrahedra that share a cornercorner with one CuS6 octahedra, corners with two CuCuS4 tetrahedra, and edges with six CuCu2S4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. The Cu–Cu bond length is 2.50 Å. There are a spread of Cu–S bond distances ranging from 2.37–2.48 Å. In the seventh Cu+1.03+ site, Cu+1.03+ is bonded in a 6-coordinate geometry to four Cu+1.03+ and six S2- atoms. There are one shorter (2.54 Å) and one longer (2.56 Å) Cu–Cu bond lengths. There are a spread of Cu–S bond distances ranging from 2.64–2.89 Å. In the eighth Cu+1.03+ site, Cu+1.03+ is bonded in a 3-coordinate geometry to five S2- atoms. There are a spread of Cu–S bond distances ranging from 2.40–3.07 Å. In the ninth Cu+1.03+ site, Cu+1.03+ is bonded in a 4-coordinate geometry to one Cu+1.03+ and four S2- atoms. There are a spread of Cu–S bond distances ranging from 2.28–2.51 Å. In the tenth Cu+1.03+ site, Cu+1.03+ is bonded to one Cu+1.03+ and four S2- atoms to form distorted CuCuS4 tetrahedra that share corners with five CuCuS4 tetrahedra, edges with two CuCu2S4 tetrahedra, and a faceface with one CuS6 octahedra. The Cu–Cu bond length is 2.45 Å. There are a spread of Cu–S bond distances ranging from 2.30–2.49 Å. In the eleventh Cu+1.03+ site, Cu+1.03+ is bonded in a 3-coordinate geometry to four S2- atoms. There are a spread of Cu–S bond distances ranging from 2.38–3.05 Å. In the twelfth Cu+1.03+ site, Cu+1.03+ is bonded in a 1-coordinate geometry to three S2- atoms. There are a spread of Cu–S bond distances ranging from 2.39–2.67 Å. In the thirteenth Cu+1.03+ site, Cu+1.03+ is bonded to two Cu+1.03+ and four S2- atoms to form distorted CuCu2S4 tetrahedra that share corners with two CuCu2S4 tetrahedra and edges with six CuCuS4 tetrahedra. There are one shorter (2.46 Å) and one longer (2.51 Å) Cu–Cu bond lengths. There are a spread of Cu–S bond distances ranging from 2.28–2.54 Å. In the fourteenth Cu+1.03+ site, Cu+1.03+ is bonded in a 4-coordinate geometry to one Cu+1.03+ and four S2- atoms. The Cu–Cu bond length is 2.56 Å. There are a spread of Cu–S bond distances ranging from 2.29–2.55 Å. In the fifteenth Cu+1.03+ site, Cu+1.03+ is bonded in a 5-coordinate geometry to four Cu+1.03+ and six S2- atoms. There are one shorter (2.45 Å) and one longer (2.57 Å) Cu–Cu bond lengths. There are a spread of Cu–S bond distances ranging from 2.61–2.97 Å. In the sixteenth Cu+1.03+ site, Cu+1.03+ is bonded in a 2-coordinate geometry to three S2- atoms. There are a spread of Cu–S bond distances ranging from 2.35–2.69 Å. In the seventeenth Cu+1.03+ site, Cu+1.03+ is bonded to one Cu+1.03+ and four S2- atoms to form distorted CuCuS4 tetrahedra that share corners with five CuCuS4 tetrahedra, edges with three CuCuS4 tetrahedra, and a faceface with one CuS6 octahedra. There are a spread of Cu–S bond distances ranging from 2.30–2.46 Å. In the eighteenth Cu+1.03+ site, Cu+1.03+ is bonded in a distorted trigonal planar geometry to three S2- atoms. There are one shorter (2.30 Å) and two longer (2.36 Å) Cu–S bond lengths. In the nineteenth Cu+1.03+ site, Cu+1.03+ is bonded to six S2- atoms to form distorted CuS6 octahedra that share corners with five CuCu2S4 tetrahedra and faces with four CuCuS4 tetrahedra. There are a spread of Cu–S bond distances ranging from 2.62–2.85 Å. In the twentieth Cu+1.03+ site, Cu+1.03+ is bonded in a 3-coordinate geometry to four S2- atoms. There are a spread of Cu–S bond distances ranging from 2.45–2.91 Å. In the twenty-first Cu+1.03+ site, Cu+1.03+ is bonded to one Cu+1.03+ and four S2- atoms to form distorted CuCuS4 tetrahedra that share corners with six CuCuS4 tetrahedra, edges with two CuCu2S4 tetrahedra, and a faceface with one CuS6 octahedra. The Cu–Cu bond length is 2.44 Å. There are a spread of Cu–S bond distances ranging from 2.31–2.47 Å. In the twenty-second Cu+1.03+ site, Cu+1.03+ is bonded to two Cu+1.03+ and four S2- atoms to form a mixture of distorted corner and edge-sharing CuCu2S4 tetrahedra. There are one shorter (2.44 Å) and one longer (2.52 Å) Cu–Cu bond lengths. There are a spread of Cu–S bond distances ranging from 2.29–2.54 Å. In the twenty-third Cu+1.03+ site, Cu+1.03+ is bonded in a 5-coordinate geometry to four Cu+1.03+ and six S2- atoms. The Cu–Cu bond length is 2.53 Å. There are a spread of Cu–S bond distances ranging from 2.62–2.96 Å. In the twenty-fourth Cu+1.03+ site, Cu+1.03+ is bonded in a 10-coordinate geometry to four Cu+1.03+ and six S2- atoms. There are one shorter (2.44 Å) and one longer (2.46 Å) Cu–Cu bond lengths. There are a spread of Cu–S bond distances ranging from 2.66–2.83 Å. In the twenty-fifth Cu+1.03+ site, Cu+1.03+ is bonded to two Cu+1.03+ and four S2- atoms to form distorted CuCu2S4 tetrahedra that share corners with three CuCuS4 tetrahedra and edges with five CuCu2S4 tetrahedra. There are a spread of Cu–S bond distances ranging from 2.29–2.55 Å. In the twenty-sixth Cu+1.03+ site, Cu+1.03+ is bonded to two Cu+1.03+ and four S2- atoms to form distorted CuCu2S4 tetrahedra that share corners with two CuCu2S4 tetrahedra and edges with five CuCuS4 tetrahedra. There are a spread of Cu–S bond distances ranging from 2.29–2.55 Å. In the twenty-seventh Cu+1.03+ site, Cu+1.03+ is bonded in a 3-coordinate geometry to four S2- atoms. There are a spread of Cu–S bond distances ranging from 2.38–3.12 Å. In the twenty-eighth Cu+1.03+ site, Cu+1.03+ is bonded in a 3-coordinate geometry to two Cu+1.03+ and five S2- atoms. There are one shorter (2.41 Å) and one longer (2.43 Å) Cu–Cu bond lengths. There are a spread of Cu–S bond distances ranging from 2.43–2.99 Å. In the twenty-ninth Cu+1.03+ site, Cu+1.03+ is bonded in a 4-coordinate geometry to two Cu+1.03+ and four S2- atoms. The Cu–Cu bond length is 2.56 Å. There are a spread of Cu–S bond distances ranging from 2.28–2.51 Å. In the thirtieth Cu+1.03+ site, Cu+1.03+ is bonded in a distorted trigonal planar geometry to one Cu+1.03+ and three S2- atoms. There are a spread of Cu–S bond distances ranging from 2.31–2.37 Å. In the thirty-first Cu+1.03+ site, Cu+1.03+ is bonded in a 3-coordinate geometry to four Cu+1.03+ and six S2- atoms. The Cu–Cu bond length is 2.48 Å. There are a spread of Cu–S bond distances ranging from 2.58–2.91 Å. In the thirty-second Cu+1.03+ site, Cu+1.03+ is bonded in a 2-coordinate geometry to three S2- atoms. There are a spread of Cu–S bond distances ranging from 2.32–2.70 Å. In the thirty-third Cu+1.03+ site, Cu+1.03+ is bonded to two Cu+1.03+ and four S2- atoms to form distorted CuCu2S4 tetrahedra that share a cornercorner with one CuS6 octahedra, corners with three CuCuS4 tetrahedra, and edges with five CuCu2S4 tetrahedra. The corner-sharing octahedral tilt angles are 53°. There are a spread of Cu–S bond distances ranging from 2.37–2.50 Å. In the thirty-fourth Cu+1.03+ site, Cu+1.03+ is bonded in a 3-coordinate geometry to four S2- atoms. There are a spread of Cu–S bond distances ranging from 2.37–3.01 Å. In the thirty-fifth Cu+1.03+ site, Cu+1.03+ is bonded to one Cu+1.03+ and four S2- atoms to form distorted CuCuS4 tetrahedra that share a cornercorner with one CuS6 octahedra, corners with six CuCuS4 tetrahedra, and edges with three CuCuS4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Cu–S bond distances ranging from 2.30–2.53 Å. In the thirty-sixth Cu+1.03+ site, Cu+1.03+ is bonded in a 1-coordinate geometry to three S2- atoms. There are a spread of Cu–S bond distances ranging from 2.36–2.68 Å. In the thirty-seventh Cu+1.03+ site, Cu+1.03+ is bonded in a distorted trigonal planar geometry to three S2- atoms. There are a spread of Cu–S bond distances ranging from 2.30–2.36 Å. In the thirty-eighth Cu+1.03+ site, Cu+1.03+ is bonded in a 3-coordinate geometry to five S2- atoms. There are a spread of Cu–S bond distances ranging from 2.39–3.11 Å. In the thirty-ninth Cu+1.03+ site, Cu+1.03+ is bonded in a 2-coordinate geometry to four S2- atoms. There are a spread of Cu–S bond distances ranging from 2.39–3.07 Å. There are twenty inequivalent S2- sites. In the first S2- site, S2- is bonded in a 8-coordinate geometry to eight Cu+1.03+ atoms. In the second S2- site, S2- is bonded in a 9-coordinate geometry to nine Cu+1.03+ atoms. In the third S2- site, S2- is bonded in a 9-coordinate geometry to nine Cu+1.03+ atoms. In the fourth S2- site, S2- is bonded in a 8-coordinate geometry to eight Cu+1.03+ atoms. In the fifth S2- site, S2- is bonded in a 4-coordinate geometry to seven Cu+1.03+ atoms. In the sixth S2- site, S2- is bonded in a 9-coordinate geometry to nine Cu+1.03+ atoms. In the seventh S2- site, S2- is bonded in a 4-coordinate geometry to ten Cu+1.03+ atoms. In the eighth S2- site, S2- is bonded in a 4-coordinate geometry to six Cu+1.03+ atoms. In the ninth S2- site, S2- is bonded in a 8-coordinate geometry to eight Cu+1.03+ atoms. In the tenth S2- site, S2- is bonded in a 4-coordinate geometry to six Cu+1.03+ atoms. In the eleventh S2- site, S2- is bonded in a 4-coordinate geometry to ten Cu+1.03+ atoms. In the twelfth S2- site, S2- is bonded in a 9-coordinate geometry to nine Cu+1.03+ atoms. In the thirteenth S2- site, S2- is bonded in a 4-coordinate geometry to seven Cu+1.03+ atoms. In the fourteenth S2- site, S2- is bonded in a 4-coordinate geometry to six Cu+1.03+ atoms. In the fifteenth S2- site, S2- is bonded in a 9-coordinate geometry to nine Cu+1.03+ atoms. In the sixteenth S2- site, S2- is bonded in a 4-coordinate geometry to seven Cu+1.03+ atoms. In the seventeenth S2- site, S2- is bonded in a 9-coordinate geometry to nine Cu+1.03+ atoms. In the eighteenth S2- site, S2- is bonded in a 9-coordinate geometry to nine Cu+1.03+ atoms. In the nineteenth S2- site, S2- is bonded in a 10-coordinate geometry to ten Cu+1.03+ atoms. In the twentieth S2- site, S2- is bonded in a 9-coordinate geometry to nine Cu+1.03+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2025

A Diazo Linker Ligand Promotes Flexibility and Induced Fit Binding in a Microporous Copper Coordination Network

Abstract Flexible organic linkers represent an intuitive and effective strategy to design flexible metal–organic materials. We report herein a systematic study concerning the effect of varying the central bond of mixed pyridyl‐benzoate linkers, L, upon the flexibility of three isostructuralkddtopology microporous coordination networks (CNs) of formula ML 2 :X‐kdd‐1‐Cu,1= L = (E)‐4‐(pyridin‐4‐yldiazenyl)benzoate;X‐kdd‐2‐Cu,2= L = (E)‐4‐(2‐(pyridin‐4‐yl)vinyl)benzoate; the previously reportedX‐kdd‐3‐Cu,3= L = 4‐(pyridin‐4‐ylethynyl)benzoate. As revealed by single crystal x‐ray diffraction (SCXRD) and gas sorption studies,X‐kdd‐1‐Cu, exhibited gate‐opening during CO 2 and hydrocarbon (C2 and C8) sorption experiments whereas the other two CNs did not. Insight into these phase transformations was gained from in situ variable‐pressure and variable temperature powder X‐ray diffraction (PXRD), SCXRD, and modeling. Rotation of ligand1around the diazo bond, torsion angle changes between phenyl and carboxylate moieties, and deformation of the Cu‐based rod building blocks enabled activatedX‐kdd‐1‐Cuto form new phases with C8 isomers and CH 2 Cl 2 , CH 2 Cl 2 inducing contraction of the activated phase. Computational studies suggest that1enables flexibility thanks to its lower barrier of deformation versus2or3. This study teaches that diazo moieties could offer a general strategy to enhance the flexibility of CNs.

Chemistry↗
DOE OSTI2020

Materials Data on CuAs2S8N8(OF7)4 by Materials Project

Cu(AsF6)2(NSF2NS(O)F2)4 crystallizes in the tetragonal I4_1/a space group. The structure is zero-dimensional and consists of four copper molecules, eight AsF6 clusters, and sixteen NSF2NS(O)F2 clusters. In each AsF6 cluster, As5+ is bonded in an octahedral geometry to six F1- atoms. There are a spread of As–F bond distances ranging from 1.77–1.79 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the third F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one As5+ atom. In each NSF2NS(O)F2 cluster, there are two inequivalent N5+ sites. In the first N5+ site, N5+ is bonded in a bent 120 degrees geometry to two S2- atoms. There is one shorter (1.52 Å) and one longer (1.60 Å) N–S bond length. In the second N5+ site, N5+ is bonded in a single-bond geometry to one S2- atom. The N–S bond length is 1.43 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded to one N5+, one O2-, and two F1- atoms to form corner-sharing SNOF2 tetrahedra. The S–O bond length is 1.41 Å. Both S–F bond lengths are 1.56 Å. In the second S2- site, S2- is bonded to two N5+ and two F1- atoms to form distorted corner-sharing SN2F2 tetrahedra. Both S–F bond lengths are 1.59 Å. O2- is bonded in a single-bond geometry to one S2- atom. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one S2- atom. In the second F1- site, F1- is bonded in a single-bond geometry to one S2- atom. In the third F1- site, F1- is bonded in a single-bond geometry to one S2- atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one S2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2024

A compact approach to higher-resolution resonant inelastic x-ray scattering detection using photoelectrons

The detection of inelastically scattered soft x-rays with high energy resolution usually requires large grating spectrometers. Recently, photoelectron spectrometry for analysis of x-rays (PAX) has been rediscovered for modern spectroscopy experiments at synchrotron light sources. By converting scattered photons to electrons and using an electron energy analyser, the energy resolution for resonant inelastic x-ray scattering (RIXS) becomes decoupled from the x-ray spot size and instrument length. In this work, we develop PAX towards high energy resolution using a modern photoemission spectroscopy setup studying Ba 2 Cu 3 O 4 Cl 2 at the Cu L 3 -edge. We measure a momentum transfer range of 24% of the first Brillouin zone simultaneously. Our results hint at the observation of a magnon excitation below 100 meV energy transfer and show intensity variations related to the dispersion of dd-excitations. With dedicated setups, PAX can complement the best and largest RIXS instruments, while at the same time opening new opportunities to acquire RIXS at a range of momentum transfers simultaneously and combine it with angle-resolved photoemission spectroscopy in a single instrument.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗