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DOE OSTI2020

Materials Data on Ce2Ga12Pd by Materials Project

Ce2PdGa12 crystallizes in the tetragonal P4/nbm space group. The structure is three-dimensional. Ce is bonded in a 6-coordinate geometry to fourteen Ga atoms. There are a spread of Ce–Ga bond distances ranging from 3.21–3.41 Å. Pd is bonded in a body-centered cubic geometry to eight equivalent Ga atoms. All Pd–Ga bond lengths are 2.58 Å. There are four inequivalent Ga sites. In the first Ga site, Ga is bonded in a 9-coordinate geometry to four equivalent Ce and five Ga atoms. There are one shorter (2.44 Å) and four longer (2.64 Å) Ga–Ga bond lengths. In the second Ga site, Ga is bonded in a 2-coordinate geometry to two equivalent Ce, two equivalent Pd, and two equivalent Ga atoms. Both Ga–Ga bond lengths are 2.64 Å. In the third Ga site, Ga is bonded in a 4-coordinate geometry to one Ce and three Ga atoms. The Ga–Ga bond length is 2.59 Å. In the fourth Ga site, Ga is bonded in a 9-coordinate geometry to four equivalent Ce and five Ga atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La2Ga12Pd by Materials Project

La2PdGa12 crystallizes in the tetragonal P4/nbm space group. The structure is three-dimensional. La is bonded in a 6-coordinate geometry to fourteen Ga atoms. There are a spread of La–Ga bond distances ranging from 3.24–3.44 Å. Pd is bonded in a body-centered cubic geometry to eight equivalent Ga atoms. All Pd–Ga bond lengths are 2.59 Å. There are four inequivalent Ga sites. In the first Ga site, Ga is bonded in a 2-coordinate geometry to two equivalent La, two equivalent Pd, and two equivalent Ga atoms. Both Ga–Ga bond lengths are 2.66 Å. In the second Ga site, Ga is bonded in a 4-coordinate geometry to one La and three Ga atoms. There are one shorter (2.58 Å) and two longer (2.66 Å) Ga–Ga bond lengths. In the third Ga site, Ga is bonded in a 9-coordinate geometry to four equivalent La and five Ga atoms. The Ga–Ga bond length is 2.50 Å. In the fourth Ga site, Ga is bonded in a 9-coordinate geometry to four equivalent La and five Ga atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KNa4Te2PdO22 by Materials Project

KNa4PdTe2O22 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. K is bonded in a 6-coordinate geometry to six O atoms. There are a spread of K–O bond distances ranging from 2.59–2.97 Å. There are four inequivalent Na sites. In the first Na site, Na is bonded in a 5-coordinate geometry to five O atoms. There are a spread of Na–O bond distances ranging from 2.20–2.66 Å. In the second Na site, Na is bonded in a 5-coordinate geometry to five O atoms. There are a spread of Na–O bond distances ranging from 2.36–2.57 Å. In the third Na site, Na is bonded in a 4-coordinate geometry to six O atoms. There are a spread of Na–O bond distances ranging from 2.21–2.98 Å. In the fourth Na site, Na is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Na–O bond distances ranging from 2.32–2.87 Å. Pd is bonded to six O atoms to form PdO6 octahedra that share an edgeedge with one PdO6 octahedra, edges with two equivalent TeO6 octahedra, and an edgeedge with one TeO6 trigonal bipyramid. There are a spread of Pd–O bond distances ranging from 1.99–2.07 Å. There are two inequivalent Te sites. In the first Te site, Te is bonded to six O atoms to form distorted TeO6 trigonal bipyramids that share an edgeedge with one PdO6 octahedra. There are a spread of Te–O bond distances ranging from 1.90–2.66 Å. In the second Te site, Te is bonded to six O atoms to form distorted TeO6 octahedra that share edges with two equivalent PdO6 octahedra. There are a spread of Te–O bond distances ranging from 1.85–2.21 Å. There are twenty-two inequivalent O sites. In the first O site, O is bonded in an L-shaped geometry to one Na and one Te atom. In the second O site, O is bonded in a distorted bent 120 degrees geometry to one Te and one O atom. The O–O bond length is 1.26 Å. In the third O site, O is bonded in a single-bond geometry to one Te atom. In the fourth O site, O is bonded in a distorted trigonal planar geometry to two Na and one Te atom. In the fifth O site, O is bonded to one K, one Na, one Pd, and one Te atom to form distorted OKNaTePd trigonal pyramids that share a cornercorner with one ONa2TePd trigonal pyramid, an edgeedge with one OKNa2Te tetrahedra, and edges with two ONa2TePd trigonal pyramids. In the sixth O site, O is bonded to two Na, one Pd, and one Te atom to form distorted ONa2TePd trigonal pyramids that share a cornercorner with one OKNaTePd trigonal pyramid, an edgeedge with one OKNa2Te tetrahedra, and edges with two OKNaTePd trigonal pyramids. In the seventh O site, O is bonded to one K, one Na, one Pd, and one Te atom to form distorted OKNaTePd trigonal pyramids that share a cornercorner with one OKNa2Te tetrahedra, an edgeedge with one OKNa2Te tetrahedra, and edges with two OKNaTePd trigonal pyramids. In the eighth O site, O is bonded in a 4-coordinate geometry to one Na, two equivalent Pd, and one Te atom. In the ninth O site, O is bonded in a water-like geometry to one Pd and one Te atom. In the tenth O site, O is bonded to one K, two Na, and one Te atom to form a mixture of distorted edge and corner-sharing OKNa2Te tetrahedra. In the eleventh O site, O is bonded in a linear geometry to one Na and one Te atom. In the twelfth O site, O is bonded in a bent 150 degrees geometry to one Na and one Te atom. In the thirteenth O site, O is bonded in a 2-coordinate geometry to two Na and one O atom. The O–O bond length is 1.24 Å. In the fourteenth O site, O is bonded in a distorted T-shaped geometry to two Na and one O atom. The O–O bond length is 1.25 Å. In the fifteenth O site, O is bonded in a bent 120 degrees geometry to one Na and one O atom. The O–O bond length is 1.25 Å. In the sixteenth O site, O is bonded in a 2-coordinate geometry to two Na and one O atom. The O–O bond length is 1.25 Å. In the seventeenth O site, O is bonded in a single-bond geometry to one O atom. In the eighteenth O site, O is bonded in a water-like geometry to one K and one Na atom. In the nineteenth O site, O is bonded in a distorted bent 120 degrees geometry to one Na and one O atom. In the twentieth O site, O is bonded in a distorted linear geometry to one K and one O atom. In the twenty-first O site, O is bonded in a bent 150 degrees geometry to one Na and one O atom. In the twenty-second O site, O is bonded in a distorted bent 150 degrees geometry to one K and one O atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2PdO6 by Materials Project

Na2PdO6 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. Na is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Na–O bond distances ranging from 2.39–2.71 Å. Pd is bonded to six O atoms to form PdO6 octahedra that share corners with four ONa2PdO tetrahedra. There are two shorter (1.89 Å) and four longer (2.11 Å) Pd–O bond lengths. There are four inequivalent O sites. In the first O site, O is bonded to two equivalent Na, one Pd, and one O atom to form distorted ONa2PdO tetrahedra that share a cornercorner with one PdO6 octahedra, corners with five ONa2PdO tetrahedra, and edges with two equivalent ONa2PdO tetrahedra. The corner-sharing octahedral tilt angles are 66°. The O–O bond length is 1.37 Å. In the second O site, O is bonded in a distorted trigonal non-coplanar geometry to two equivalent Na and one Pd atom. In the third O site, O is bonded to two equivalent Na, one Pd, and one O atom to form distorted ONa2PdO tetrahedra that share a cornercorner with one PdO6 octahedra, corners with five ONa2PdO tetrahedra, and edges with two equivalent ONa2PdO tetrahedra. The corner-sharing octahedral tilt angles are 66°. In the fourth O site, O is bonded in a distorted trigonal non-coplanar geometry to two equivalent Na and one Pd atom.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Effect of the Selective Halogenation of Small Molecule Acceptors on the Blend Morphology and Voltage Loss of High-Performance Solar Cells

Herein, the impacts of the selective halogenation at two different positions of dicyanomethylene-3-indanone (IC) end groups and inner side chains of small molecular acceptors (SMAs) on the P D :SMA interfacial interactions, blend morphology, and resulting photovoltaic properties are described. In this study, four different SMAs (A1, A2, A3, and A4) with the same molecular backbone, but with different degrees of halogenation, are synthesized. The IC end groups on the backbones of the A1 and A3, and A2 and A4 SMAs are chlorinated and fluorinated, respectively; in addition, 6-phenoxyhexyl inner side chains of the A3 and A4 are chlorinated. The SMAs are paired with a chlorinated PBDT-Cl PD to construct organic solar cells (OSCs). The PBDT-Cl:A4-based OSC exhibits the highest power conversion efficiency of 17.2%, outperforming the PBDT-Cl:A1-(13.3%), PBDT-Cl:A2-(15.6%), and PBDT-Cl:A3-based OSC (16.5%). The Cl atoms on the side chains in the A3 and A4 SMAs enhance the molecular/energetic interactions at the P D :SMA interfaces and improve the blend morphology in terms of domain purity and spacing. These effects lead to the improved fill factors and reduced voltage loss of the PBDT-Cl:A3- and PBDT-Cl:A4-based OSCs. This study demonstrates the importance of appropriate halogenation of SMAs in optimizing the blend morphology, reducing voltage loss, and improving OSC performance.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Decoupling size and surface effects of intermetallic CuPd nanocrystals for electrocatalytic nitrate reduction to ammonia

Nitrate pollution poses a major environmental challenge, but its electrochemical conversion to ammonia offers a sustainable waste-to-value solution. Here, in this study, we synthesized monodisperse, size-tunable B2-phase CuPd intermetallic nanocrystals (6–46 nm) and studied their performance in the electrochemical nitrate reduction reaction (eNO 3 RR). By using bromide ions to modulate Pd reduction and applying mild annealing, we achieved phase-pure B2 structures across all sizes. Catalytic testing revealed a volcano-like trend in ammonia yield, peaking at 33 nm nanocubes with a rate of 6.97 mol h −1 g −1 at −0.6 V vs. reversible hydrogen electrode (RHE). This optimum reflects a balance between the increased surface area of smaller particles and the enhanced exposure of active (100) facets in larger ones. Theoretical calculations indicated that the B2-CuPd (100) facet is favorable for nitrate adsorption, thereby supporting the high activity of nanocubes. Our results highlight the critical role of tuning both nanoparticle size and surface structure to maximize eNO 3 RR efficiency.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Machine-learning guided search for phonon-mediated superconductivity in boron and carbon compounds

We present a workflow that iteratively combines ab-initio calculations with a machine-learning (ML) guided search for superconducting compounds with both dynamical stability and instability from imaginary phonon modes, the latter of which have been largely overlooked in previous studies. Electron-phonon coupling (EPC) properties and critical temperature (T c ) of 417 boron, carbon, and borocarbide compounds have been calculated with density functional perturbation theory (DFPT) and isotropic Eliashberg approximation. Our study addresses T c convergence of Brillouin zone sampling with an ansatz test, stabilizing imaginary phonon modes for significant EPC contributions, and comparing the performance of two ML models, especially when including compounds of dynamical instability. We predict a few promising superconducting compounds with formation energy just above the ground state convex hull, such as Ca 5 B 3 N 6 (35 K), TaNbC 2 (28.4 K), Nb 3 B 3 C (16.4 K), Y 2 B 3 C 2 (4.0 K), Pd 3 CaB (7.0 K), MoRuB 2 (15.6 K), RuVB 2 (15.0 K), RuSc 3 C 4 (6.6 K) among others.

Nepal, Niraj K. [Ames Laboratory (AMES), Ames, IA ↗
DOE OSTI2020

Materials Data on KLaPdO3 by Materials Project

KLaPdO3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. K1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.72–3.04 Å. La3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of La–O bond distances ranging from 2.39–2.66 Å. Pd2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Pd–O bond distances ranging from 2.03–2.10 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to three equivalent K1+, two equivalent La3+, and one Pd2+ atom to form distorted OK3La2Pd octahedra that share corners with five equivalent OK2La3Pd octahedra and edges with eight OK3La2Pd octahedra. The corner-sharing octahedra tilt angles range from 6–8°. In the second O2- site, O2- is bonded to two equivalent K1+, three equivalent La3+, and one Pd2+ atom to form a mixture of distorted corner and edge-sharing OK2La3Pd octahedra. The corner-sharing octahedra tilt angles range from 6–8°. In the third O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent K1+, two equivalent La3+, and two equivalent Pd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba2Ca(PdO2)3 by Materials Project

Ba2Ca(PdO2)3 crystallizes in the orthorhombic Fmmm space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are four shorter (2.79 Å) and four longer (2.83 Å) Ba–O bond lengths. In the second Ba2+ site, Ba2+ is bonded in a 10-coordinate geometry to six O2- atoms. There are four shorter (2.87 Å) and two longer (3.26 Å) Ba–O bond lengths. Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are four shorter (2.39 Å) and two longer (2.46 Å) Ca–O bond lengths. There are two inequivalent Pd2+ sites. In the first Pd2+ site, Pd2+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (2.07 Å) and two longer (2.08 Å) Pd–O bond lengths. In the second Pd2+ site, Pd2+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Pd–O bond lengths are 2.06 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to two Ba2+, one Ca2+, and two Pd2+ atoms to form a mixture of distorted corner, edge, and face-sharing OBa2CaPd2 square pyramids. In the second O2- site, O2- is bonded in a 6-coordinate geometry to three Ba2+, one Ca2+, and two equivalent Pd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Andrieslombaardite, RhSbS, a new platinum-group mineral from the platiniferous Onverwacht Pipe, Republic of South Africa

A hundred years after the discovery of the Merensky Reef in 1924, it is appropriate to present the new mineral andrieslombaardite in honour of Andries Frederik Lombaard who was instrumental in its discovery. Andrieslombaardite, RhSbS, was first described as an unknown mineral from placer deposits associated with the Tulameen Alaskan-Uralian type complex, British Colombia, Canada (Raicevic and Cabri, 1976) but has since been reported from several other deposits including the platiniferous Driekop, Mooihoek, and Onverwacht pipes in the eastern Bushveld Complex, South Africa. The mineral and the name were approved by the Commission on New Minerals Nomenclature and Classification (CNMNC) of the International Mineralogical Association (IMA no. 2022-076) based on data in the co-type samples from Onverwacht and a co-type sample from the Yubdo stream, Birbir River, Ethiopia. Andrieslombaardite in the Onverwacht sample is a single 8 x 20 μm grain attached to laurite in a matrix of altered silicate and Fe-oxyhydroxide minerals. In the Yubdo samples, there are many grains of pale brownish gray andrieslombaardite up to 25 x 55 μm in size, included in Pt-Fe alloys, some associated with erlichmanite, and others attached to bornite and chalcopyrite. The reflectance values (R%) measured in air and in oil at the COM wavelengths are 48.3 and 33.0 (470 nm), 49.3 and 34.0 (546 nm), 51.0 and 35.9 (589 nm), and 51.8 and 36.7 (650 nm). The colour values x, y, Y, λd, and Pe in air are 0.317, 0.322, 50.3, 580, and 3.2, and in oil are 0.319, 0.324, 35.6, 579, and 4.5. The composition of andrieslombaardite is ideally RhSbS, but it contains variable amounts of Fe, Pt, Pd, and Ir that may substitute for Rh. The mineral is cubic with unit-cell dimensions of a = 6.0278(4) Å, V = 219.01(6) Å 3 and Z = 4. It was synthesised at 400 and 550°C using stoichiometric elemental amounts. It is a member of the cobaltite group. The mineralisation of the intrusive dunite pipes was probably introduced at high temperatures, under magmatic conditions. The primary assemblages were to a certain degree overprinted and redistributed by low-temperature hydrothermal fluids. The Pt-Fe alloys from Yubdo containing PGM inclusions such as andrieslombaardite in the Yubdo-Alaskan-type complex were formed at some post-magmatic stage owing to PGE remobilisation during hydrothermal or metamorphic episodes.

58 GEOSCIENCES↗
DOE OSTI2020

Materials Data on PdN4Cl2O by Materials Project

Pd(N2)2Cl2O crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional and consists of four nitrogen molecules, two palladium molecules, and one Cl2O framework. In the Cl2O framework, O2- is bonded in a 8-coordinate geometry to four equivalent Cl1- atoms. All O–Cl bond lengths are 3.70 Å. Cl1- is bonded in a 6-coordinate geometry to two equivalent O2- and four equivalent Cl1- atoms. All Cl–Cl bond lengths are 3.91 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Pd(II) and Rh(I) Catalytic Precursors for Arene Alkenylation: Comparative Evaluation of Reactivity and Mechanism Based on Experimental and Computational Studies

We combine experimental and computational investigations to compare and understand catalytic arene alkenylation using the Pd(II) and Rh(I) precursors Pd(OAc) 2 and [(η 2 -C 2 H 4 ) 2 Rh(µ-OAc)] 2 with arene, olefin and Cu(II) carboxylate at elevated temperature (> 120 °C). Under specific conditions, previous computational and experimental efforts have identified heterotrimetallic cyclic PdCu 2 (η 2 -C 2 H 4 ) 3 (μ-OPiv) 6 and [(η 2 -C 2 H 4 ) 2 Rh(µ-OPiv) 2 ] 2 (µ-Cu) (OPiv = pivalate) species as likely active catalysts for these processes. Further studies of catalyst speciation suggest a complicated equilibrium between Cu(II)-containing complexes containing one Rh or Pd atom with complexes containing two Rh or Pd atoms. At 120 °C, Rh catalysis produces styrene > 20-fold more rapidly than Pd. Also, at 120 °C, Rh is ~98% selective for styrene formation while Pd is ~82% selective. Furthermore, our studies indicate that Pd catalysis has a higher predilection toward olefin functionalization to form undesired vinyl ester, while Rh catalysis is more selective for arene/olefin coupling. However, at elevated temperatures, Pd converts vinyl ester and arene to vinyl arene, which is proposed to occur through low valent Pd(0) clusters that are formed in situ. Regardless of arene functionality, the regioselectivity for alkenylation of mono-substituted arenes with the Rh catalyst gives an approximate 2:1 meta:para ratio with minimal ortho C–H activation. In contrast, Pd selectivity is significantly influenced by arene electronics with electron-rich arenes giving an approximate 1:2:2 ortho:meta:para ratio while the electron deficient (α,α,α)-trifluorotoluene gives a 3:1 meta:para ratio with minimal ortho functionalization. Kinetic intermolecular arene ethenylation competition experiments find that Rh reacts most rapidly with benzene, and the rate of mono-substituted arene alkenylation does not correlate with arene electronics. In contrast, with Pd catalysis, electron-rich arenes react more rapidly than benzene while electron-deficient arenes react less rapidly than benzene. These experimental findings, in combination with computational results, are consistent with the arene C–H activation step for Pd catalysis involving significant η 1 -arenium character due to Pd-mediated electrophilic aromatic substitution character. In contrast, the mechanism for Rh catalysis is not sensitive to arene substituent electronics, which we propose indicates less electrophilic aromatic substitution character for the Rh-mediated arene C–H activation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on La4PdO7 by Materials Project

La4PdO7 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent La3+ sites. In the first La3+ site, La3+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of La–O bond distances ranging from 2.40–3.00 Å. In the second La3+ site, La3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of La–O bond distances ranging from 2.32–2.79 Å. Pd2+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (2.05 Å) and two longer (2.06 Å) Pd–O bond lengths. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to four La3+ atoms to form OLa4 tetrahedra that share corners with seven equivalent OLa5Pd octahedra, corners with six OLa4 tetrahedra, an edgeedge with one OLa5Pd octahedra, and edges with four OLa4 tetrahedra. The corner-sharing octahedra tilt angles range from 14–73°. In the second O2- site, O2- is bonded to five La3+ and one Pd2+ atom to form distorted OLa5Pd octahedra that share a cornercorner with one OLa5Pd octahedra, corners with eleven OLa4 tetrahedra, edges with four equivalent OLa5Pd octahedra, and edges with four OLa4 tetrahedra. The corner-sharing octahedral tilt angles are 0°. In the third O2- site, O2- is bonded to four La3+ atoms to form OLa4 tetrahedra that share corners with four equivalent OLa5Pd octahedra, corners with six OLa4 tetrahedra, edges with three equivalent OLa5Pd octahedra, and edges with three OLa4 tetrahedra. The corner-sharing octahedra tilt angles range from 17–62°. In the fourth O2- site, O2- is bonded in a 6-coordinate geometry to four La3+ and two equivalent Pd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Palladium/Zeolite Low Temperature Passive NOx Adsorbers (PNA): Structure-Adsorption Property Relationships for Hydrothermally Aged PNA Materials

Zeolites with different framework structures (SSZ-13, ZSM-5, BEA) but similar Si/Al ratios and Pd loading (~1 wr%) were synthesized and evaluated as low temperature passive NOx adsorbers (PNA). These materials exhibit high NOx adsorption efficiency with atomically dispersed Pd the active adsorption site. Hydrothermal aging at 750 ºC for 16 hours in the presence of 10% water vapor in air resulted in the formation of PdO nanoparticles in all three samples as evidenced by high energy XRD. Hydrothermal aging of the small-pore Pd/SSZ-13 (Si/Al = 6), which contain ~100-90% atomically dispersed palladium ions, decreases its PNA performance only by ~10-20%. High-field solid state 27Al NMR studies on the fresh and aged samples substantiate dealumination and significant changes in the distribution of Al (and thus, Bronsted acid) sites after hydrothermal aging. FTIR measurements with NO probe molecule and titration of Bronsted acid sites with nitrosyl (NO+) ions further corroborate the 27Al NMR data. Because framework aluminum atoms are the anchoring sites for atomically dispersed Pd ions, their elution from the framework causes the loss of active atomically dispersed Pd species. Furthermore, with the aid of HAADF-STEM imaging and synchrotron XRD studies, we further confirm and visualize the fate of these Pd species – they agglomerate into PdO nanoparticles on the external surface of zeolite. Consequently, these changes lead to the decrease in PNA performance of these materials after hydrothermal aging. The thus formed agglomerates cannot be re-dispersed back to their ionic state due to the loss of framework Al T-sites and/or inherent stability of such large PdO particles. Our study clearly demonstrates that, unlike in previous studies that found increased PNA performance upon HTA , high temperatures hydrothermal aging of PNA materials that contain atomically dispersed Pd initially, results in a decrease in NOx storage efficiency due mostly to the formation of PdO agglomerates. However, we also highlight the high hydrothermal stability of predominantly atomically dispersed 1-3 wt% Pd/SSZ-13 (Si/Al = 6), whose performance decreases only marginally after prolonged hydrothermal aging at 750 ºC. Overall, this study shows that hydrothermally stable passive NOx materials can be prepared using small-pore SSZ-13 zeolite.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on KSmPdO3 by Materials Project

KSmPdO3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. K1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.65–3.04 Å. Sm3+ is bonded to seven O2- atoms to form distorted edge-sharing SmO7 hexagonal pyramids. There are a spread of Sm–O bond distances ranging from 2.31–2.58 Å. Pd2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Pd–O bond distances ranging from 2.00–2.10 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent K1+, three equivalent Sm3+, and one Pd2+ atom to form distorted OK2Sm3Pd octahedra that share corners with five equivalent OK3Sm2Pd octahedra and edges with eight OK2Sm3Pd octahedra. The corner-sharing octahedra tilt angles range from 8–10°. In the second O2- site, O2- is bonded to three equivalent K1+, two equivalent Sm3+, and one Pd2+ atom to form a mixture of distorted edge and corner-sharing OK3Sm2Pd octahedra. The corner-sharing octahedra tilt angles range from 8–10°. In the third O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent K1+, two equivalent Sm3+, and two equivalent Pd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KPrPdO3 by Materials Project

KPrPdO3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. K1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.69–3.03 Å. Pr3+ is bonded to seven O2- atoms to form distorted edge-sharing PrO7 hexagonal pyramids. There are a spread of Pr–O bond distances ranging from 2.38–2.62 Å. Pd2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Pd–O bond distances ranging from 2.01–2.10 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent K1+, three equivalent Pr3+, and one Pd2+ atom to form distorted OK2Pr3Pd octahedra that share corners with five equivalent OK3Pr2Pd octahedra and edges with eight OK2Pr3Pd octahedra. The corner-sharing octahedra tilt angles range from 7–8°. In the second O2- site, O2- is bonded to three equivalent K1+, two equivalent Pr3+, and one Pd2+ atom to form a mixture of distorted edge and corner-sharing OK3Pr2Pd octahedra. The corner-sharing octahedra tilt angles range from 7–8°. In the third O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent K1+, two equivalent Pr3+, and two equivalent Pd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KPd2O3 by Materials Project

KPd2O3 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. K is bonded in a 6-coordinate geometry to six equivalent O atoms. There are three shorter (2.70 Å) and three longer (2.82 Å) K–O bond lengths. There are two inequivalent Pd sites. In the first Pd site, Pd is bonded in an octahedral geometry to six equivalent O atoms. All Pd–O bond lengths are 2.07 Å. In the second Pd site, Pd is bonded in a square co-planar geometry to four equivalent O atoms. All Pd–O bond lengths are 2.06 Å. O is bonded to two equivalent K and three Pd atoms to form a mixture of distorted edge and corner-sharing OK2Pd3 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ni2PdSe2 by Materials Project

PdNi2Se2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are three inequivalent Pd2+ sites. In the first Pd2+ site, Pd2+ is bonded in a square co-planar geometry to four equivalent Se2- atoms. All Pd–Se bond lengths are 2.60 Å. In the second Pd2+ site, Pd2+ is bonded in a square co-planar geometry to four equivalent Se2- atoms. All Pd–Se bond lengths are 2.53 Å. In the third Pd2+ site, Pd2+ is bonded in a linear geometry to two equivalent Se2- atoms. Both Pd–Se bond lengths are 2.70 Å. Ni1+ is bonded in a see-saw-like geometry to four Se2- atoms. There are two shorter (2.35 Å) and two longer (2.41 Å) Ni–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 6-coordinate geometry to two Pd2+ and four equivalent Ni1+ atoms. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to one Pd2+ and four equivalent Ni1+ atoms.

36 MATERIALS SCIENCE↗