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DOE OSTI2020

Materials Data on BaNd2PtO5 by Materials Project

BaNd2PtO5 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Ba2+ is bonded in a q6 geometry to ten O2- atoms. There are two shorter (3.00 Å) and eight longer (3.05 Å) Ba–O bond lengths. Nd3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Nd–O bond distances ranging from 2.33–2.61 Å. Pt2+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Pt–O bond lengths are 2.03 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Ba2+ and four equivalent Nd3+ atoms to form corner-sharing OBa2Nd4 octahedra. The corner-sharing octahedra tilt angles range from 0–34°. In the second O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Ba2+, three equivalent Nd3+, and one Pt2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaLa2PtO5 by Materials Project

BaLa2PtO5 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Ba2+ is bonded in a distorted q6 geometry to ten O2- atoms. There are two shorter (3.00 Å) and eight longer (3.07 Å) Ba–O bond lengths. La3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of La–O bond distances ranging from 2.34–2.69 Å. Pt2+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Pt–O bond lengths are 2.04 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Ba2+ and four equivalent La3+ atoms to form corner-sharing OBa2La4 octahedra. The corner-sharing octahedra tilt angles range from 0–33°. In the second O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Ba2+, three equivalent La3+, and one Pt2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Direct Evidence for a Sequential Electron Transfer–Proton Transfer Mechanism in the PCET Reduction of a Metal Hydroxide Catalyst

Here, the proton-coupled electron transfer (PCET) mechanism for the reaction M ox -OH + e − + H + → M red -OH 2 was de-termined through kinetic resolution of the independent electron transfer (ET) and proton transfer (PT) steps. The reaction of interest was triggered by visible light excitation of [Ru II (tpy)(bpy′)H 2 O] 2+ , Ru II -OH 2 , where tpy is 2,2′:6′,2″-terpyridine and bpy′ is 4,4′-diaminopropylsilatrane-2,2′-bipyridine, anchored to In 2 O 3 :Sn (ITO) thin films in aqueous solutions. Interfacial kinetics for the PCET reduction reaction were quantified by nanosecond transient absorption spectroscopy as a function of solution pH and applied potential. Data acquired from pH = 5-10 revealed a stepwise electron-transfer proton-transfer (ET-PT) mechanism, while kinetic measurements made below the pK a (Ru III -OH/OH 2 ) = 1.3 were used to study the analogous interfacial reaction where electron transfer was the only mechanistic step. Analysis of this data with a recently reported multi-channel kinetic model was used to construct a PCET zone diagram and supported the assignment of an ET-PT mechanism from pH = 5-10. Ultimately, this study represents a unique example amongst M ox -OH/M red -OH 2 reactivity where the protona-tion and oxidation state of the intermediate was kinetically and spectrally resolved to firmly establish the PCET mechanism.

Charge transfer↗
DOE OSTI2020

Materials Data on BaGd2PtO5 by Materials Project

BaGd2PtO5 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Ba2+ is bonded in a distorted q6 geometry to ten O2- atoms. There are two shorter (2.98 Å) and eight longer (3.01 Å) Ba–O bond lengths. Gd3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Gd–O bond distances ranging from 2.26–2.57 Å. Pt2+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Pt–O bond lengths are 2.03 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Ba2+ and four equivalent Gd3+ atoms to form distorted corner-sharing OBa2Gd4 octahedra. The corner-sharing octahedra tilt angles range from 0–33°. In the second O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Ba2+, three equivalent Gd3+, and one Pt2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K4Mo6PtO26 by Materials Project

K4Mo6PtO26 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are four inequivalent K sites. In the first K site, K is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of K–O bond distances ranging from 2.69–3.07 Å. In the second K site, K is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of K–O bond distances ranging from 2.78–3.29 Å. In the third K site, K is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of K–O bond distances ranging from 2.75–3.10 Å. In the fourth K site, K is bonded in a 6-coordinate geometry to six O atoms. There are a spread of K–O bond distances ranging from 2.78–3.19 Å. There are six inequivalent Mo sites. In the first Mo site, Mo is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.74–2.31 Å. In the second Mo site, Mo is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.73–2.33 Å. In the third Mo site, Mo is bonded in a 4-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.74–2.44 Å. In the fourth Mo site, Mo is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.74–2.41 Å. In the fifth Mo site, Mo is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.74–2.31 Å. In the sixth Mo site, Mo is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.73–2.32 Å. Pt is bonded in an octahedral geometry to six O atoms. There are a spread of Pt–O bond distances ranging from 1.87–2.05 Å. There are twenty-six inequivalent O sites. In the first O site, O is bonded in a distorted single-bond geometry to one K and one Mo atom. In the second O site, O is bonded in a distorted single-bond geometry to one K and one Mo atom. In the third O site, O is bonded in a distorted single-bond geometry to two K and one Mo atom. In the fourth O site, O is bonded in a distorted bent 120 degrees geometry to one K and one Mo atom. In the fifth O site, O is bonded in a distorted single-bond geometry to one K and one Mo atom. In the sixth O site, O is bonded in a distorted single-bond geometry to two K and one Mo atom. In the seventh O site, O is bonded in a distorted single-bond geometry to two K and one Mo atom. In the eighth O site, O is bonded in a distorted bent 150 degrees geometry to one K and one Mo atom. In the ninth O site, O is bonded in a distorted single-bond geometry to two K and one Mo atom. In the tenth O site, O is bonded in a 1-coordinate geometry to two K and one Mo atom. In the eleventh O site, O is bonded in a distorted single-bond geometry to three K and one Mo atom. In the twelfth O site, O is bonded in a distorted bent 120 degrees geometry to one K and one Mo atom. In the thirteenth O site, O is bonded in a bent 120 degrees geometry to two Mo atoms. In the fourteenth O site, O is bonded in a distorted bent 120 degrees geometry to one K and two Mo atoms. In the fifteenth O site, O is bonded in a distorted water-like geometry to one Mo and one Pt atom. In the sixteenth O site, O is bonded in a distorted trigonal planar geometry to one K and two Mo atoms. In the seventeenth O site, O is bonded in a bent 120 degrees geometry to two Mo atoms. In the eighteenth O site, O is bonded in a bent 120 degrees geometry to two Mo atoms. In the nineteenth O site, O is bonded in a distorted single-bond geometry to one K, one Mo, and one Pt atom. In the twentieth O site, O is bonded in a distorted trigonal planar geometry to one K and two Mo atoms. In the twenty-first O site, O is bonded in a distorted trigonal non-coplanar geometry to two Mo and one Pt atom. In the twenty-second O site, O is bonded in a distorted trigonal non-coplanar geometry to two Mo and one Pt atom. In the twenty-third O site, O is bonded to three Mo and one Pt atom to form distorted corner-sharing OMo3Pt trigonal pyramids. In the twenty-fourth O site, O is bonded to three Mo and one Pt atom to form distorted corner-sharing OMo3Pt trigonal pyramids. In the twenty-fifth O site, O is bonded in a distorted T-shaped geometry to three K atoms. In the twenty-sixth O site, O is bonded in a bent 120 degrees geometry to two K atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nd2Mo6PtO38 by Materials Project

Nd2Mo6PtO38 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Nd is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Nd–O bond distances ranging from 2.35–2.59 Å. There are three inequivalent Mo sites. In the first Mo site, Mo is bonded in a 5-coordinate geometry to five O atoms. There are a spread of Mo–O bond distances ranging from 1.70–2.14 Å. In the second Mo site, Mo is bonded in a 5-coordinate geometry to five O atoms. There are a spread of Mo–O bond distances ranging from 1.72–2.22 Å. In the third Mo site, Mo is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.77–2.26 Å. Pt is bonded in an octahedral geometry to six O atoms. There are four shorter (2.02 Å) and two longer (2.19 Å) Pt–O bond lengths. There are nineteen inequivalent O sites. In the first O site, O is bonded in a distorted bent 120 degrees geometry to one Pt and one O atom. The O–O bond length is 1.25 Å. In the second O site, O is bonded in a trigonal non-coplanar geometry to two Mo and one Pt atom. In the third O site, O is bonded in a trigonal non-coplanar geometry to two Mo and one Pt atom. In the fourth O site, O is bonded in a distorted trigonal non-coplanar geometry to one Nd and two Mo atoms. In the fifth O site, O is bonded in a bent 150 degrees geometry to two Mo atoms. In the sixth O site, O is bonded in a bent 120 degrees geometry to two Mo atoms. In the seventh O site, O is bonded in a bent 150 degrees geometry to one Nd and one Mo atom. In the eighth O site, O is bonded in a distorted water-like geometry to one Nd and one Mo atom. In the ninth O site, O is bonded in a single-bond geometry to one Mo atom. In the tenth O site, O is bonded in a single-bond geometry to one Mo atom. In the eleventh O site, O is bonded in a single-bond geometry to one Mo atom. In the twelfth O site, O is bonded in a bent 150 degrees geometry to one Nd and one Mo atom. In the thirteenth O site, O is bonded in a bent 120 degrees geometry to one Nd and one O atom. The O–O bond length is 1.34 Å. In the fourteenth O site, O is bonded in a single-bond geometry to one Nd atom. In the fifteenth O site, O is bonded in a single-bond geometry to one Nd atom. In the sixteenth O site, O is bonded in a bent 120 degrees geometry to two O atoms. The O–O bond length is 1.26 Å. In the seventeenth O site, O is bonded in a distorted single-bond geometry to one Nd atom. In the eighteenth O site, O is bonded in a single-bond geometry to one O atom. In the nineteenth O site, O is bonded in a single-bond geometry to one O atom.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Platinum on High-Entropy Aluminate Spinels as Thermally Stable CO Oxidation Catalysts

Thermal degradation is a leading cause of automotive catalyst deactivation. Because high-entropy oxides are uniquely stabilized at high temperatures via an increase in configurational entropy, these materials may offer new mechanisms for preventing the thermal deactivation of precious metal catalysts. In this work, we evaluated platinum loaded on simple and high-entropy aluminate spinels (MAl 2 O 4 , where M = Co, Cu, Mg, Ni, or mixtures thereof) in carbon monoxide oxidation before and after aging at 800 °C. Pt supported on all simple spinels showed significant deactivation after thermal aging compared to the fresh samples, with T 90 increasing by at least 60 °C. However, Pt on high-entropy spinels had nearly the same or better activity after aging, with T 90 increasing by only 6 °C at most. During aging and reduction, copper exsolved from the spinel supports and alloyed with platinum. This interaction promoted low temperature oxidation activity, presumably through weakened CO binding, but did not prevent deactivation. On the other hand, Co, Mg, and Ni constituents promoted stronger CO bonding, as evidenced by apparent negative order kinetics and poor activity at low temperatures. High-entropy spinels, containing a variety of active metals, displayed synergetic reactant adsorption capacity and cooperative effects with supported platinum particles, which collectively prevented thermal deactivation.

CO oxidation↗
DOE OSTI2020

Materials Data on Ba6Y2Ru3PtO18 by Materials Project

Ba6Y2Ru3PtO18 is (Cubic) Perovskite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. there are six inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent RuO6 octahedra, faces with seven BaO12 cuboctahedra, a faceface with one PtO6 octahedra, faces with three equivalent YO6 octahedra, and faces with three equivalent RuO6 octahedra. The corner-sharing octahedral tilt angles are 14°. There are a spread of Ba–O bond distances ranging from 2.97–3.07 Å. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent RuO6 octahedra, faces with seven BaO12 cuboctahedra, a faceface with one RuO6 octahedra, faces with three equivalent YO6 octahedra, and faces with three equivalent PtO6 octahedra. The corner-sharing octahedral tilt angles are 11°. There are a spread of Ba–O bond distances ranging from 2.98–3.20 Å. In the third Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent PtO6 octahedra, faces with seven BaO12 cuboctahedra, faces with three equivalent YO6 octahedra, and faces with four RuO6 octahedra. The corner-sharing octahedral tilt angles are 10°. There are a spread of Ba–O bond distances ranging from 2.93–3.16 Å. In the fourth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent RuO6 octahedra, faces with seven BaO12 cuboctahedra, faces with three equivalent YO6 octahedra, and faces with four RuO6 octahedra. The corner-sharing octahedral tilt angles are 13°. There are a spread of Ba–O bond distances ranging from 2.90–3.17 Å. In the fifth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve BaO12 cuboctahedra, faces with six BaO12 cuboctahedra, faces with two YO6 octahedra, faces with three equivalent RuO6 octahedra, and faces with three equivalent PtO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.99–3.05 Å. In the sixth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve BaO12 cuboctahedra, faces with six BaO12 cuboctahedra, faces with two YO6 octahedra, and faces with six RuO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.97–3.01 Å. There are two inequivalent Y3+ sites. In the first Y3+ site, Y3+ is bonded to six O2- atoms to form YO6 octahedra that share corners with three equivalent RuO6 octahedra, corners with three equivalent PtO6 octahedra, and faces with eight BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are three shorter (2.19 Å) and three longer (2.26 Å) Y–O bond lengths. In the second Y3+ site, Y3+ is bonded to six O2- atoms to form YO6 octahedra that share corners with six RuO6 octahedra and faces with eight BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are three shorter (2.22 Å) and three longer (2.24 Å) Y–O bond lengths. There are three inequivalent Ru+4.67+ sites. In the first Ru+4.67+ site, Ru+4.67+ is bonded to six O2- atoms to form RuO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent YO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one RuO6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are three shorter (1.96 Å) and three longer (2.05 Å) Ru–O bond lengths. In the second Ru+4.67+ site, Ru+4.67+ is bonded to six O2- atoms to form RuO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent YO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one RuO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (1.98 Å) and three longer (2.05 Å) Ru–O bond lengths. In the third Ru+4.67+ site, Ru+4.67+ is bonded to six O2- atoms to form RuO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent YO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one PtO6 octahedra. The corner-sharing octahedral tilt angles are 3°. There are three shorter (1.94 Å) and three longer (2.07 Å) Ru–O bond lengths. Pt4+ is bonded to six O2- atoms to form PtO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent YO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one RuO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.00 Å) and three longer (2.07 Å) Pt–O bond lengths. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Y3+, and one Ru+4.67+ atom. In the second O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Y3+, and one Ru+4.67+ atom. In the third O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Y3+, and one Ru+4.67+ atom. In the fourth O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Y3+, and one Pt4+ atom. In the fifth O2- site, O2- is bonded to four Ba2+, one Ru+4.67+, and one Pt4+ atom to form a mixture of distorted corner and face-sharing OBa4RuPt octahedra. The corner-sharing octahedra tilt angles range from 6–60°. In the sixth O2- site, O2- is bonded in a 6-coordinate geometry to four Ba2+ and two Ru+4.67+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Using anion photoelectron spectroscopy of cluster models to gain insights into mechanisms of catalyst-mediated H 2 production from water

We report that metal oxide cluster models of catalyst materials offer a powerful platform for probing the molecular-scale features and interactions that govern catalysis. This perspective gives an overview of studies implementing the combination of anion photoelectron (PE) spectroscopy and density functional theory calculations toward exploring cluster models of metal oxides and metal-oxide supported Pt that catalytically drive the hydrogen evolution reaction (HER) or the water–gas shift reaction. The utility in the combination of these experimental and computational techniques lies in our ability to unambiguously determine electronic and molecular structures, which can then connect to results of reactivity studies. In particular, we focus on the activity of oxygen vacancies modeled by suboxide clusters, the critical mechanistic step of forming proximal metal hydride and hydroxide groups as a prerequisite for H2 production, and the structural features that lead to trapped dihydroxide groups. The pronounced asymmetric oxidation found in heterometallic group 6 oxides and near-neighbor group 5/group 6 results in higher activity toward water, while group 7/group 6 oxides form very specific stoichiometries that suggest facile regeneration. Studies on the trans-periodic combination of cerium oxide and platinum as a model for ceria supported Pt atoms and nanoparticles reveal striking negative charge accumulation by Pt, which, combined with the ionic conductivity of ceria, suggests a mechanism for the exceptionally high activity of this system towards the water–gas shift reaction.

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

Platinum Graphene Catalytic Condenser for Millisecond Programmable Metal Surfaces

Accelerating catalytic chemistry and tuning surface reactions require precise control of the electron density of metal atoms. In this work, nanoclusters of platinum were supported on a graphene sheet within a catalytic condenser device that facilitated electron or hole accumulation in the platinum active sites with negative or positive applied potential, respectively. The catalytic condenser was fabricated by depositing on top of a p-type Si wafer an amorphous HfO 2 dielectric (70 nm), on which was placed the active layer of 2–4 nm platinum nanoclusters on graphene. A potential of ±6 V applied to the Pt/graphene layer relative to the silicon electrode moved electrons into or out of the active sites of Pt, attaining charge densities more than 1% of an electron or hole per surface Pt atom. At a level of charge condensation of ±10% of an electron per surface atom, the binding energy of carbon monoxide to a Pt(111) surface was computed via density functional theory to change 24 kJ mol –1 (0.25 eV), which was consistent with the range of carbon monoxide binding energies determined from temperature-programmed desorption (ΔBE CO of 20 ± 1 kJ mol –1 or 0.19 eV) and equilibrium surface coverage measurements (ΔBE CO of 14 ± 1 kJ mol –1 or 0.14 eV). Impedance spectroscopy indicated that Pt/graphene condensers with potentials oscillating at 3000 Hz exhibited negligible loss in capacitance and charge accumulation, enabling programmable surface conditions at amplitudes and frequencies necessary to achieve catalytic resonance.

Inorganic carbon compounds↗
DOE OSTI2021

Ab Initio modeling of Near-Edge EELS spectra for chemisorbed molecules

Abstract Electron energy loss spectroscopy (EELS) has recently been applied to probe chemisorbed molecules on metal nanostructures, but a fundamental understanding of the correlation between these spectra and the electronic structures of the adsorbates has been limited. We report here on the insights afforded by time-dependent density functional theory to decipher the energy loss near edge structure (ELNES) of EELS spectra associated with chemisorption. These first-principles calculations simulate the ELNES-EELS spectra for chemisorbed CO on various facets of Au and Pt. Computational predictions of key signatures such as the ‘red shift’ and reductions in the peak intensity of the 2 π * and 6 σ * peaks, as compared to free CO in the gas phase, are validated in comparison to experimentally collected EELS spectra. These signatures are revealed to arise from changes in the electronic structure in terms of unoccupied density of states associated with the chemisorption process. They are consistent with a Blyholder model that incorporates donation and back-donation of electrons. They are also characteristic of the chemisorption process, such as the choice of metal, site of adsorption and the coverage and distribution of adsorbates. Our simulations thus provide guidelines for the use of ELNES-EELS to characterize the atomic structure and adsorption property of nanostructured surfaces and facilitate the development of advanced nanomaterials for catalytic applications.

Materials Science↗
DOE OSTI2020

Materials Data on Tl2HPtC5N5O by Materials Project

PtTl2C5N5HO crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of one PtTl2C5N5HO sheet oriented in the (1, 0, 0) direction. Pt2+ is bonded in a distorted single-bond geometry to one O2- atom. The Pt–O bond length is 2.09 Å. There are two inequivalent Tl1+ sites. In the first Tl1+ site, Tl1+ is bonded in a 6-coordinate geometry to five N3- and one O2- atom. There are a spread of Tl–N bond distances ranging from 2.90–3.40 Å. The Tl–O bond length is 2.68 Å. In the second Tl1+ site, Tl1+ is bonded in a 6-coordinate geometry to five N3- and one O2- atom. There are a spread of Tl–N bond distances ranging from 3.05–3.16 Å. The Tl–O bond length is 2.78 Å. There are five inequivalent C+2.40+ sites. In the first C+2.40+ site, C+2.40+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. In the second C+2.40+ site, C+2.40+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. In the third C+2.40+ site, C+2.40+ is bonded in a distorted single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. In the fourth C+2.40+ site, C+2.40+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. In the fifth C+2.40+ site, C+2.40+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. There are five inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted single-bond geometry to one Tl1+ and one C+2.40+ atom. In the second N3- site, N3- is bonded in a distorted single-bond geometry to two Tl1+ and one C+2.40+ atom. In the third N3- site, N3- is bonded in a distorted single-bond geometry to three Tl1+ and one C+2.40+ atom. In the fourth N3- site, N3- is bonded in a distorted single-bond geometry to two equivalent Tl1+ and one C+2.40+ atom. In the fifth N3- site, N3- is bonded in a distorted single-bond geometry to two equivalent Tl1+ and one C+2.40+ atom. H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. O2- is bonded in a distorted single-bond geometry to one Pt2+, two Tl1+, and one H1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

From Trivial Kondo Insulator Ce 3 Pt 3 Bi 4 to Topological Nodal-Line Semimetal Ce 3 Pd 3 Bi 4

In this work, using the density functional theory combined with dynamical mean-field theory, we have performed systematic study of the electronic structure and its band topology properties of Ce 3 Pt 3 Bi 4 and Ce 3 Pd 3 Bi 4 . At high temperatures ( ~ 290 K ), the electronic structures of both compounds resemble the open-core 4 f density functional calculation results. For Ce 3 Pt 3 Bi 4 , clear hybridization gap can be observed below 72 K, and its coherent momentum-resolved spectral function below 18 K exhibits an topologically trivial indirect gap of ~ 6 meV and resembles density functional band structure with itinerant 4 f state. For Ce 3 Pd 3 Bi 4 , no clear hybridization gap can be observed down to 4 K, and its momentum-resolved spectral function resembles electron-doped open-core 4 f density functional calculations. The band nodal points of Ce 3 Pd 3 Bi 4 at 4 K are protected by the gliding-mirror symmetry and form ringlike structure. Therefore, the Ce 3 Pt 3 Bi 4 compound is topologically trivial Kondo insulator while the Ce 3 Pd 3 Bi 4 compound is topological nodal-line semimetal.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Yb2Ge6Pt by Materials Project

Yb2PtGe6 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are two inequivalent Yb sites. In the first Yb site, Yb is bonded in a 10-coordinate geometry to ten Ge atoms. There are a spread of Yb–Ge bond distances ranging from 3.07–3.30 Å. In the second Yb site, Yb is bonded in a 8-coordinate geometry to four equivalent Pt and ten Ge atoms. All Yb–Pt bond lengths are 3.14 Å. There are a spread of Yb–Ge bond distances ranging from 3.15–3.50 Å. Pt is bonded in a 9-coordinate geometry to four equivalent Yb and five Ge atoms. There are a spread of Pt–Ge bond distances ranging from 2.44–2.57 Å. There are six inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to two equivalent Yb, two equivalent Pt, and five Ge atoms. There are one shorter (2.48 Å) and four longer (2.90 Å) Ge–Ge bond lengths. In the second Ge site, Ge is bonded in a 7-coordinate geometry to two equivalent Yb and five Ge atoms. All Ge–Ge bond lengths are 2.90 Å. In the third Ge site, Ge is bonded in a 6-coordinate geometry to six Yb and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.47 Å. In the fourth Ge site, Ge is bonded in a 1-coordinate geometry to six Yb, one Pt, and two equivalent Ge atoms. In the fifth Ge site, Ge is bonded in a 7-coordinate geometry to two equivalent Yb and five Ge atoms. The Ge–Ge bond length is 2.48 Å. In the sixth Ge site, Ge is bonded in a 2-coordinate geometry to two equivalent Yb, two equivalent Pt, and five Ge atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Perturbation theory approach to predict the covariance matrices of the galaxy power spectrum and bispectrum in redshift space

In this paper, we predict the covariance matrices of both the power spectrum and the bispectrum, including full non-Gaussian contributions, redshift space distortions, linear bias effects, and shot-noise corrections, using perturbation theory (PT). To quantify the redshift-space distortion effect, we focus mainly on the monopole and quadrupole components of both the power and bispectra. We, for the first time, compute the 5- and 6-point spectra to predict the cross-covariance between the power and bispectra, and the autocovariance of the bispectrum in redshift space. Further, we test the validity of our calculations by comparing them with the covariance matrices measured from the MultiDark-Patchy mock catalogues that are designed to reproduce the galaxy clustering measured from the Baryon Oscillation Spectroscopic Survey Data Release 12. We argue that the simple, leading-order PT works because the shot-noise corrections for the Patchy mocks are more dominant than other higher order terms we ignore. In the meantime, we confirm some discrepancies in the comparison, especially of the cross-covariance. We discuss potential sources of such discrepancies. We also show that our PT model reproduces well the cumulative signal-to-noise ratio of the power spectrum and the bispectrum as a function of maximum wavenumber, implying that our PT model captures successfully essential contributions to the covariance matrices.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2026

Supramolecular Assembly of Multielement Ribbon-like Structures Derived from Halide Perovskites

Halide perovskites are crucial materials with broad applications owing to their exceptional optoelectronic properties. Vacancy-ordered double perovskites, featuring highly tunable transition metal sites, enable controllable optoelectronic properties through multielement compositional design. Here, in this study, we introduced 18-crown-6 into the vacancy-ordered double perovskites system and developed two-dimensional ribbon-like single crystals (18C6@K) 2 {PtSnTeIrRe} 1 Cl 6 via an antisolvent supramolecular assembly method, demonstrating morphology modulation through multielement composition design. The crystals crystallize in the centrosymmetric space group $P\bar{1}$. The dumbbell-shaped structural units (crown ether@A)2MX6 pack along a and b axes to form a 2-dimensional (2D) monolayer, and these monolayers further stack along the c axis to generate the ribbon-like single crystals. Energy-dispersive X-ray spectroscopy (EDX) qualitatively confirmed the uniform distribution of the five transition metals throughout the crystal, while inductively coupled plasma atomic emission spectroscopy (ICP–AES) quantitatively verified their atomic ratios. We further investigated the origin of the morphology, distinct from the previously reported cube-like single crystals with the $R\bar{3}$ space group. When acetonitrile was used as the solvent, three-dimensional crystals with $R\bar{3}$ symmetry were obtained, whereas dimethylformamide (DMF) was essential for forming two-dimensional ribbon-like single crystals. The essential role of DMF could be ascribed to its capability to maintain a higher concentration of the building blocks. Moreover, Ir 4+ and Pt 4+ cations also played critical roles in inducing the two-dimensional ribbon-like morphology. The three-element (18C6@K) 2 {PtSnTe}1Cl 6 single crystals exhibited bright yellow emission under 375 nm laser excitation, demonstrating the tunability of optoelectronic properties of this class of material.

Zhu, Heqing [University of California, Berkeley, C↗
DOE OSTI2020

Materials Data on Ba17Tm16Zn8Pt4O57 by Materials Project

Ba17Tm16Pt4Zn8O57 crystallizes in the tetragonal I4/m space group. The structure is three-dimensional. there are five inequivalent Ba sites. In the first Ba site, Ba is bonded in a 9-coordinate geometry to nine O atoms. There are a spread of Ba–O bond distances ranging from 2.61–3.10 Å. In the second Ba site, Ba is bonded in a 6-coordinate geometry to ten O atoms. There are a spread of Ba–O bond distances ranging from 2.74–3.32 Å. In the third Ba site, Ba is bonded in a 10-coordinate geometry to ten O atoms. There are a spread of Ba–O bond distances ranging from 2.74–3.25 Å. In the fourth Ba site, Ba is bonded in a 10-coordinate geometry to eight O atoms. There are a spread of Ba–O bond distances ranging from 2.85–2.97 Å. In the fifth Ba site, Ba is bonded in a distorted q6 geometry to ten O atoms. There are two shorter (2.86 Å) and eight longer (2.92 Å) Ba–O bond lengths. There are four inequivalent Tm sites. In the first Tm site, Tm is bonded to seven O atoms to form distorted TmO7 pentagonal bipyramids that share corners with two equivalent PtO6 octahedra, edges with two equivalent TmO7 pentagonal bipyramids, edges with two equivalent ZnO5 trigonal bipyramids, and a faceface with one PtO6 octahedra. The corner-sharing octahedral tilt angles are 12°. There are a spread of Tm–O bond distances ranging from 2.20–2.53 Å. In the second Tm site, Tm is bonded to seven O atoms to form distorted TmO7 pentagonal bipyramids that share corners with two equivalent ZnO5 trigonal bipyramids, edges with three TmO7 pentagonal bipyramids, an edgeedge with one ZnO5 trigonal bipyramid, and a faceface with one PtO6 octahedra. There are a spread of Tm–O bond distances ranging from 2.26–2.38 Å. In the third Tm site, Tm is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of Tm–O bond distances ranging from 2.27–2.46 Å. In the fourth Tm site, Tm is bonded to seven O atoms to form distorted TmO7 pentagonal bipyramids that share a cornercorner with one TmO7 pentagonal bipyramid, corners with two equivalent ZnO5 trigonal bipyramids, an edgeedge with one TmO7 pentagonal bipyramid, edges with two equivalent ZnO5 trigonal bipyramids, and faces with two equivalent TmO7 pentagonal bipyramids. There are a spread of Tm–O bond distances ranging from 2.26–2.43 Å. Pt is bonded to six O atoms to form PtO6 octahedra that share corners with two equivalent TmO7 pentagonal bipyramids, corners with two equivalent ZnO5 trigonal bipyramids, and faces with two TmO7 pentagonal bipyramids. There are a spread of Pt–O bond distances ranging from 2.05–2.11 Å. There are two inequivalent Zn sites. In the first Zn site, Zn is bonded to five O atoms to form distorted ZnO5 trigonal bipyramids that share corners with two equivalent PtO6 octahedra and edges with three TmO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 13°. There are a spread of Zn–O bond distances ranging from 1.96–2.14 Å. In the second Zn site, Zn is bonded to five O atoms to form distorted ZnO5 trigonal bipyramids that share corners with four TmO7 pentagonal bipyramids and edges with two equivalent TmO7 pentagonal bipyramids. There are a spread of Zn–O bond distances ranging from 1.98–2.15 Å. There are ten inequivalent O sites. In the first O site, O is bonded to four equivalent Ba, one Tm, and one Pt atom to form OBa4TmPt octahedra that share corners with nine OBa3TmZnPt octahedra, edges with five equivalent OBa4TmPt octahedra, and faces with two equivalent OBa3TmZnPt octahedra. The corner-sharing octahedra tilt angles range from 4–55°. In the second O site, O is bonded in a 4-coordinate geometry to two Ba, three Tm, and one Zn atom. In the third O site, O is bonded in a 6-coordinate geometry to three Ba, two Tm, and one Pt atom. In the fourth O site, O is bonded in a 4-coordinate geometry to one Ba, three Tm, and one Zn atom. In the fifth O site, O is bonded to five Ba and one Zn atom to form distorted OBa5Zn octahedra that share corners with eight OBa5Zn octahedra, edges with eight OBa5Zn octahedra, and faces with two equivalent OBa3TmZnPt octahedra. The corner-sharing octahedra tilt angles range from 13–55°. In the sixth O site, O is bonded to three Ba, one Tm, one Pt, and one Zn atom to form a mixture of distorted corner and face-sharing OBa3TmZnPt octahedra. The corner-sharing octahedra tilt angles range from 46–58°. In the seventh O site, O is bonded to two Ba, three Tm, and one Zn atom to form distorted OBa2Tm3Zn octahedra that share corners with ten OBa5Zn octahedra, edges with two equivalent OBa2Tm3Zn octahedra, and faces with four OBa2Tm4 octahedra. The corner-sharing octahedra tilt angles range from 0–76°. In the eighth O site, O is bonded to four Ba, one Tm, and one Pt atom to form distorted OBa4TmPt octahedra that share corners with eight OBa4TmPt octahedra, edges with five OBa5Zn octahedra, and faces with two equivalent OBa3TmZnPt octahedra. The corner-sharing octahedra tilt angles range from 3–59°. In the ninth O site, O is bonded to four Ba, one Tm, and one Zn atom to form distorted OBa4TmZn octahedra that share corners with nine OBa3TmZnPt octahedra, edges with five OBa5Zn octahedra, and faces with two equivalent OBa2Tm3Zn octahedra. The corner-sharing octahedra tilt angles range from 3–58°. In the tenth O site, O is bonded to two equivalent Ba and four equivalent Tm atoms to form OBa2Tm4 octahedra that share corners with ten OBa2Tm4 octahedra and faces with eight equivalent OBa2Tm3Zn octahedra. The corner-sharing octahedra tilt angles range from 0–60°.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Development of a Transferable Density-Functional Tight-Binding Model for Organic Molecules at the Water/Platinum Interface

A computationally efficient and transferable approach for modeling reactions at metal/water interfaces could significantly accelerate our understanding and ultimately the development of new catalytic transformations, particularly in the context of the emerging field of biomass conversion. Here, we present a parametrization of Pt–X (X = H, O, C) density-functional tight-binding (DFTB) for addressing this need. We first constructed Pt–H, Pt–O, and Pt–C repulsive potential splines. These pairwise parameters were then augmented to include many-body interactions using the Chebyshev Interaction Model for Efficient Simulation (ChIMES). We compare the geometrical and energetic performances of both DFTB and DFTB/ChIMES methods with DFT reference data across a variety of organic molecules at the platinum surface from nanoparticles to single-crystal surfaces. DFTB shows limited transferability between extended crystal surfaces and small nanoparticles. This transferability is significantly improved through the introduction of three-body interactions with Pt in DFTB/ChIMES, which provides consistent results across various systems, with reductions in the RMSD from around 30 kcal/mol in DFTB to around 10 kcal/mol. We demonstrate the stability and reliability of the obtained parameters by performing metadynamic simulations for the adsorption of phenol on Pt(111). We observe that DFTB itself is undersolvating the surface, leading to only one or two chemisorbed water molecules in a c(4 × 6) unit cell. In contrast, DFTB/ChIMES leads to a coverage of about 0.5 ML and successfully captures the chemisorbed mode of phenol at both the solid/liquid and the solid/gas interfaces. Furthermore, in agreement with experimental measurements, the adsorption at the solid/liquid interface is significantly weaker than that at the solid/gas interface. As a result, we highlight that even with DFTB, where we can accumulate dynamics for more than 1 ns for a given system, the simulations are not fully converged.

Adsorption↗