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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Rb2Ag4Pd3(NO2)12 by Materials Project

(RbAg2(NO2)6)2(Pd)3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of six palladium molecules and one RbAg2(NO2)6 framework. In the RbAg2(NO2)6 framework, Rb1+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Rb–O bond distances ranging from 2.92–3.36 Å. There are two inequivalent Ag+1.50+ sites. In the first Ag+1.50+ site, Ag+1.50+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Ag–O bond distances ranging from 2.41–2.52 Å. In the second Ag+1.50+ site, Ag+1.50+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Ag–O bond distances ranging from 2.41–2.61 Å. There are six inequivalent N+2.33+ sites. In the first N+2.33+ site, N+2.33+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.24 Å) and one longer (1.25 Å) N–O bond length. In the second N+2.33+ site, N+2.33+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.24 Å) and one longer (1.25 Å) N–O bond length. In the third N+2.33+ site, N+2.33+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.24 Å) and one longer (1.26 Å) N–O bond length. In the fourth N+2.33+ site, N+2.33+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.24 Å) and one longer (1.26 Å) N–O bond length. In the fifth N+2.33+ site, N+2.33+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both N–O bond lengths are 1.25 Å. In the sixth N+2.33+ site, N+2.33+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both N–O bond lengths are 1.25 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one Rb1+ and one N+2.33+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one Rb1+, one Ag+1.50+, and one N+2.33+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to one Rb1+, one Ag+1.50+, and one N+2.33+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to one Rb1+ and one N+2.33+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to one Rb1+, one Ag+1.50+, and one N+2.33+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to one Rb1+ and one N+2.33+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Ag+1.50+ and one N+2.33+ atom. In the eighth O2- site, O2- is bonded in a single-bond geometry to one Rb1+ and one N+2.33+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ag+1.50+ and one N+2.33+ atom. In the tenth O2- site, O2- is bonded in a 1-coordinate geometry to one Rb1+, one Ag+1.50+, and one N+2.33+ atom. In the eleventh O2- site, O2- is bonded in a distorted single-bond geometry to one Rb1+, one Ag+1.50+, and one N+2.33+ atom. In the twelfth O2- site, O2- is bonded in a distorted single-bond geometry to one Rb1+, one Ag+1.50+, and one N+2.33+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nd2Sb3Pd by Materials Project

Nd2PdSb3 crystallizes in the tetragonal P4/mmm space group. The structure is one-dimensional and consists of one Nd2PdSb3 ribbon oriented in the (0, 0, 1) direction. Nd3+ is bonded in a linear geometry to one Pd2+ and one Sb+2.67- atom. The Nd–Pd bond length is 2.54 Å. The Nd–Sb bond length is 2.81 Å. Pd2+ is bonded in a linear geometry to two equivalent Nd3+ atoms. There are two inequivalent Sb+2.67- sites. In the first Sb+2.67- site, Sb+2.67- is bonded in a distorted single-bond geometry to one Nd3+ and one Sb+2.67- atom. The Sb–Sb bond length is 2.66 Å. In the second Sb+2.67- site, Sb+2.67- is bonded in a linear geometry to two equivalent Sb+2.67- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K4PdPt(NO2)8 by Materials Project

(K(NO2)2)4PtPd crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of two palladium molecules, two platinum molecules, and one K(NO2)2 framework. In the K(NO2)2 framework, there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.81–3.14 Å. In the second K1+ site, K1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of K–O bond distances ranging from 2.74–3.23 Å. There are four inequivalent N3+ sites. In the first N3+ site, N3+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both N–O bond lengths are 1.25 Å. In the second N3+ site, N3+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both N–O bond lengths are 1.25 Å. In the third N3+ site, N3+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.25 Å) and one longer (1.26 Å) N–O bond length. In the fourth N3+ site, N3+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both N–O bond lengths are 1.25 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent K1+ and one N3+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two K1+ and one N3+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent K1+ and one N3+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one N3+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one N3+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to three K1+ and one N3+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent K1+ and one N3+ atom. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent K1+ and one N3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Reduction-Controlled Atomic Migration for Single Atom Alloy Library

Here, picturing the atomic migration pathways of catalysts in a reactive atmosphere is of central significance for uncovering the underlying catalytic mechanisms and directing the design of high-performance catalysts. Here, we describe a reduction-controlled atomic migration pathway that converts nanoparticles to single atom alloys (SAAs), which has remained synthetically challenging in prior attempts due to the elusive mechanism. We achieved this by thermally treating the noble-metal nanoparticles M (M = Ru, Rh, Pd, Ag, Ir, Pt, and Au) on metal oxide (CuO) supports with H2/Ar. Atomic-level characterization revealed such conversion as the synergistic consequence of noble metal-promoted H2 dissociation and concomitant CuO reduction. The observed atomic migration pathway offers an understanding of the dynamic mechanisms study of nanomaterials formation and catalyst design.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Size-Dependent Energy and Adhesion of Pd Nanoparticles on Graphene on Ni(111) by Pd Vapor Adsorption Calorimetry

Carbon-supported late transition-metal nanoparticles are promising catalysts and electrocatalysts for wide-ranging applications. However, experimental investigations of the bonding energetics of metal nanoparticles on carbon supports are very limited. Here, in this work, we report heats of adsorption of Pd vapor deposited onto single-layer graphene(0001) supported on Ni(111) at 100 and 300 K as Pd grows particles of well-defined size in the range from three atom clusters to 6 nm diameter. Sizes were determined from He + low-energy ion scattering (LEIS). In this size range, the differential heat of Pd adsorption increases from 228 kJ/mol to within 10 kJ/mol of the heat of sublimation of bulk Pd (377 kJ/mol). The chemical potential of metal atoms in these nanoparticles as a function of average particle size was determined from these results. The adhesion energy at the Pd/graphene(0001)/Ni(111) interface was extracted from these data and found to be 3.5 J/m 2 for the largest Pd particles. For the three metal elements that have now been studied (Pd, Ni, and Ag), we found an increase in metal/graphene(0001)/Ni(111) adhesion energy with metal carbophilicity, which we defined here as the heat of C atom adsorption on that metal’s (111) surface estimated from published density functional theory calculations.

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

Semi-grand canonical Monte Carlo simulation of the acrolein induced surface segregation and aggregation of AgPd with machine learning surrogate models

The single atom alloy of AgPd has been found to be a promising catalyst for the selective hydrogenation of acrolein. It is also known that the formation of Pd islands on the surface will greatly reduce the selectivity of the reaction. As a result, the surface segregation and aggregation of Pd on the AgPd surface under reaction conditions of selective hydrogenation of acrolein are of great interest. In this work, we lay out a workflow that can predict the surface segregation and aggregation of Pd on a FCC(111) AgPd surface with and without the presence of acrolein. We use machine learning surrogate models to predict the AgPd bulk energy, AgPd slab energy, and acrolein adsorption energy on AgPd slabs. Then, we use the semi-grand canonical Monte Carlo simulation to predict the surface segregation and aggregation under different bulk Pd concentrations. Under vacuum conditions, our method predicts that only trace amount of Pd will exist on the surface at Pd bulk concentrations less than 20%. However, with the presence of acrolein, Pd will start to aggregate as dimers on the surface at Pd bulk concentrations as low as 6.5%.

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

Materials Data on K2Ag4Pd3(NO2)12 by Materials Project

(KAg2(NO2)6)2(Pd)3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of six palladium molecules and one KAg2(NO2)6 framework. In the KAg2(NO2)6 framework, K1+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of K–O bond distances ranging from 2.81–3.47 Å. There are two inequivalent Ag+1.50+ sites. In the first Ag+1.50+ site, Ag+1.50+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ag–O bond distances ranging from 2.40–3.00 Å. In the second Ag+1.50+ site, Ag+1.50+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ag–O bond distances ranging from 2.41–3.11 Å. There are six inequivalent N+2.33+ sites. In the first N+2.33+ site, N+2.33+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.24 Å) and one longer (1.26 Å) N–O bond length. In the second N+2.33+ site, N+2.33+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both N–O bond lengths are 1.25 Å. In the third N+2.33+ site, N+2.33+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.24 Å) and one longer (1.25 Å) N–O bond length. In the fourth N+2.33+ site, N+2.33+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both N–O bond lengths are 1.25 Å. In the fifth N+2.33+ site, N+2.33+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.24 Å) and one longer (1.26 Å) N–O bond length. In the sixth N+2.33+ site, N+2.33+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.24 Å) and one longer (1.26 Å) N–O bond length. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two Ag+1.50+ and one N+2.33+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ag+1.50+ and one N+2.33+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to one K1+, one Ag+1.50+, and one N+2.33+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to one K1+, one Ag+1.50+, and one N+2.33+ atom. In the fifth O2- site, O2- is bonded in a single-bond geometry to one K1+, one Ag+1.50+, and one N+2.33+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to one K1+, one Ag+1.50+, and one N+2.33+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to one K1+, one Ag+1.50+, and one N+2.33+ atom. In the eighth O2- site, O2- is bonded in a single-bond geometry to one K1+, two Ag+1.50+, and one N+2.33+ atom. In the ninth O2- site, O2- is bonded in a distorted single-bond geometry to one K1+, one Ag+1.50+, and one N+2.33+ atom. In the tenth O2- site, O2- is bonded in a distorted single-bond geometry to one K1+, one Ag+1.50+, and one N+2.33+ atom. In the eleventh O2- site, O2- is bonded in a 1-coordinate geometry to one K1+, one Ag+1.50+, and one N+2.33+ atom. In the twelfth O2- site, O2- is bonded in a distorted single-bond geometry to one K1+, one Ag+1.50+, and one N+2.33+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Te2PdBr6 by Materials Project

PdTe2Br6 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four PdTe2Br6 clusters. Pd4+ is bonded in an L-shaped geometry to two Br1- atoms. There are one shorter (2.51 Å) and one longer (2.58 Å) Pd–Br bond lengths. There are two inequivalent Te1+ sites. In the first Te1+ site, Te1+ is bonded in a distorted rectangular see-saw-like geometry to four Br1- atoms. There are a spread of Te–Br bond distances ranging from 2.58–3.07 Å. In the second Te1+ site, Te1+ is bonded in a 4-coordinate geometry to four Br1- atoms. There are a spread of Te–Br bond distances ranging from 2.53–3.35 Å. There are six inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a single-bond geometry to one Te1+ atom. In the second Br1- site, Br1- is bonded in a single-bond geometry to one Te1+ atom. In the third Br1- site, Br1- is bonded in a distorted L-shaped geometry to one Pd4+ and one Te1+ atom. In the fourth Br1- site, Br1- is bonded in a single-bond geometry to one Te1+ atom. In the fifth Br1- site, Br1- is bonded in a distorted single-bond geometry to two Te1+ atoms. In the sixth Br1- site, Br1- is bonded in a 1-coordinate geometry to one Pd4+ and two Te1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pd(PbCl3)2 by Materials Project

Pd(PbCl3)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Pd2+ is bonded in a distorted square co-planar geometry to four Cl1- atoms. There are two shorter (2.33 Å) and two longer (2.34 Å) Pd–Cl bond lengths. Pb2+ is bonded in a 8-coordinate geometry to eight Cl1- atoms. There are a spread of Pb–Cl bond distances ranging from 2.86–3.54 Å. There are three inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a distorted trigonal planar geometry to three equivalent Pb2+ atoms. In the second Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Pd2+ and three equivalent Pb2+ atoms. In the third Cl1- site, Cl1- is bonded in a 1-coordinate geometry to one Pd2+ and two equivalent Pb2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2PdN2(ClO2)2 by Materials Project

K2PdN2(O2Cl)2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. K1+ is bonded to five O2- and three equivalent Cl1- atoms to form distorted edge-sharing KCl3O5 hexagonal bipyramids. There are a spread of K–O bond distances ranging from 2.88–3.12 Å. There are a spread of K–Cl bond distances ranging from 3.18–3.23 Å. Pd2+ is bonded in a distorted square co-planar geometry to two equivalent N3+ and two equivalent Cl1- atoms. Both Pd–N bond lengths are 2.06 Å. Both Pd–Cl bond lengths are 2.33 Å. N3+ is bonded in a distorted bent 120 degrees geometry to one Pd2+ and two O2- atoms. There is one shorter (1.25 Å) and one longer (1.26 Å) N–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to three equivalent K1+ and one N3+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent K1+ and one N3+ atom. Cl1- is bonded in a 4-coordinate geometry to three equivalent K1+ and one Pd2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KZrPdF7 by Materials Project

KZrPdF7 crystallizes in the orthorhombic Pnna space group. The structure is three-dimensional. K1+ is bonded in a 10-coordinate geometry to ten F1- atoms. There are a spread of K–F bond distances ranging from 2.76–3.13 Å. Zr4+ is bonded to seven F1- atoms to form ZrF7 pentagonal bipyramids that share corners with four equivalent PdF6 octahedra and an edgeedge with one PdF6 octahedra. The corner-sharing octahedra tilt angles range from 37–48°. There are a spread of Zr–F bond distances ranging from 2.03–2.17 Å. Pd2+ is bonded to six F1- atoms to form PdF6 octahedra that share corners with four equivalent ZrF7 pentagonal bipyramids and an edgeedge with one ZrF7 pentagonal bipyramid. There are four shorter (2.20 Å) and two longer (2.23 Å) Pd–F bond lengths. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a 2-coordinate geometry to one K1+, one Zr4+, and one Pd2+ atom. In the second F1- site, F1- is bonded in a 2-coordinate geometry to one K1+, one Zr4+, and one Pd2+ atom. In the third F1- site, F1- is bonded in a distorted single-bond geometry to two equivalent K1+ and one Zr4+ atom. In the fourth F1- site, F1- is bonded in a 3-coordinate geometry to two equivalent K1+, one Zr4+, and one Pd2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KHfPdF7 by Materials Project

KHfPdF7 crystallizes in the orthorhombic Pnna space group. The structure is three-dimensional. K1+ is bonded in a 10-coordinate geometry to ten F1- atoms. There are a spread of K–F bond distances ranging from 2.75–3.11 Å. Hf4+ is bonded to seven F1- atoms to form HfF7 pentagonal bipyramids that share corners with four equivalent PdF6 octahedra and an edgeedge with one PdF6 octahedra. The corner-sharing octahedra tilt angles range from 36–47°. There are a spread of Hf–F bond distances ranging from 2.00–2.14 Å. Pd2+ is bonded to six F1- atoms to form PdF6 octahedra that share corners with four equivalent HfF7 pentagonal bipyramids and an edgeedge with one HfF7 pentagonal bipyramid. There are four shorter (2.20 Å) and two longer (2.23 Å) Pd–F bond lengths. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a 2-coordinate geometry to one K1+, one Hf4+, and one Pd2+ atom. In the second F1- site, F1- is bonded in a 2-coordinate geometry to one K1+, one Hf4+, and one Pd2+ atom. In the third F1- site, F1- is bonded in a distorted single-bond geometry to two equivalent K1+ and one Hf4+ atom. In the fourth F1- site, F1- is bonded in a 3-coordinate geometry to two equivalent K1+, one Hf4+, and one Pd2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs2HgPdCl6 by Materials Project

Cs2PdHgCl6 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Cs1+ is bonded to twelve Cl1- atoms to form CsCl12 cuboctahedra that share corners with twelve equivalent CsCl12 cuboctahedra, faces with six equivalent CsCl12 cuboctahedra, faces with four equivalent PdCl6 octahedra, and faces with four equivalent HgCl6 octahedra. There are four shorter (3.84 Å) and eight longer (3.89 Å) Cs–Cl bond lengths. Pd2+ is bonded to six Cl1- atoms to form distorted PdCl6 octahedra that share corners with six equivalent HgCl6 octahedra and faces with eight equivalent CsCl12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.34 Å) and two longer (3.20 Å) Pd–Cl bond lengths. Hg2+ is bonded to six Cl1- atoms to form HgCl6 octahedra that share corners with six equivalent PdCl6 octahedra and faces with eight equivalent CsCl12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.36 Å) and four longer (3.05 Å) Hg–Cl bond lengths. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a distorted single-bond geometry to four equivalent Cs1+, one Pd2+, and one Hg2+ atom. In the second Cl1- site, Cl1- is bonded in a 2-coordinate geometry to four equivalent Cs1+, one Pd2+, and one Hg2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Engineering catalyst supports to stabilize PdO x two-dimensional rafts for water-tolerant methane oxidation

The treatment of emissions from natural gas engines is an important area of research since methane is a potent greenhouse gas. The benchmark catalysts, based on Pd, still face challenges such as water poisoning and long-term stability. In this work, we report an approach for catalyst synthesis that relies on the trapping of metal single atoms on the support surface, in thermally stable form, to modify the nature of further deposited metal/metal oxide. By anchoring Pt ions on a catalyst support we can tailor the morphology of the deposited phase. In particular, two-dimensional (2D) rafts of PdO x are formed, resulting in higher reaction rates and improved water tolerance during methane oxidation. The results show that modifying the support by trapping single atoms could provide an important addition to the toolkit of catalyst designers for controlling the nucleation and growth of metal and metal oxide clusters in heterogeneous catalysts.

2D raft↗
DOE OSTI2020

Materials Data on CoH12PdC4(NO3)4 by Materials Project

Co(CO3)4PdN4H12 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional and consists of two PdN4H12 clusters and one Co(CO3)4 framework. In each PdN4H12 cluster, Pd4+ is bonded in a square co-planar geometry to four equivalent N3- atoms. All Pd–N bond lengths are 2.06 Å. N3- is bonded in a distorted trigonal non-coplanar geometry to one Pd4+ and three H1+ atoms. All N–H bond lengths are 1.03 Å. There are three inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the Co(CO3)4 framework, Co4+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with four equivalent OO4 tetrahedra. There is two shorter (1.75 Å) and four longer (1.95 Å) Co–O bond length. C4+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.24 Å) and one longer (1.31 Å) C–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a water-like geometry to one Co4+ and one C4+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one C4+ and one O2- atom. The O–O bond length is 2.78 Å. In the third O2- site, O2- is bonded in a single-bond geometry to one Co4+ and two equivalent O2- atoms. Both O–O bond lengths are 2.85 Å. In the fourth O2- site, O2- is bonded to four O2- atoms to form OO4 tetrahedra that share corners with two equivalent CoO6 octahedra and an edgeedge with one OO4 tetrahedra. The corner-sharing octahedral tilt angles are 51°.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Modeling plasma-induced surface charge effects on CO 2 activation by single atom catalysts supported on reducible and irreducible metal oxides

Abstract The accumulation of negative surface charge on catalytic surfaces in the presence of low-temperature plasma (LTP) could influence catalytic performance. However, it is difficult to disentangle the role of surface charging and other LTP catalytic effects in experiment. Herein, we use density functional theory (DFT) modeling to understand the effect of plasma-induced surface charging on CO 2 activation by atomically dispersed single atom (SA) catalysts on both reducible and irreducible metal oxide supports. We model CO 2 adsorption strength and CO 2 dissociation barriers for Co 1 , Ni 1 , Cu 1 , Rh 1 , Pd 1 , and Ag 1 SAs on both reducible and irreducible supports, namely, CeO 2 (100), TiO 2 (101), and γ -Al 2 O 3 (110), to elucidate trends. We find that accumulated surface charge on the SA increases the CO 2 adsorption strength and decreases the CO 2 dissociation barrier for all studied SA/support combinations. For both charged and uncharged (neutral) systems, SAs on the reducible CeO 2 (100) support generally adsorb CO 2 more weakly compared to when on irreducible supports like γ -Al 2 O 3 (110). SAs on γ -Al 2 O 3 (110) typically have larger barriers for CO 2 dissociation for both charged and uncharged systems compared to TiO 2 (101) and CeO 2 (100). The magnitude of surface charging effects on CO 2 binding energies and dissociation barriers depends sensitively on both the SA and the support. In some cases, the CO 2 activation trends qualitatively change between neutral and charged systems for a fixed SA across different supports. This DFT modeling study demonstrates that surface charging should be considered in strong electric fields because it can have a large effect on molecule adsorption and bond-breaking on catalytic surfaces.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

Materials Data on Rb2Pd(NO3)4 by Materials Project

Rb2Pd(NO3)4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Rb1+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Rb–O bond distances ranging from 2.96–3.50 Å. Pd2+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (2.03 Å) and two longer (2.04 Å) Pd–O bond lengths. There are two inequivalent N5+ sites. In the first N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.24–1.33 Å. In the second N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.24–1.32 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Rb1+ and one N5+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Rb1+, one Pd2+, and one N5+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Rb1+ and one N5+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one Rb1+ and one N5+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Rb1+ and one N5+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Rb1+, one Pd2+, and one N5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2P2PdO7 by Materials Project

K2PdP2O7 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.75–3.01 Å. In the second K1+ site, K1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of K–O bond distances ranging from 2.86–3.25 Å. Pd2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are two shorter (2.04 Å) and two longer (2.06 Å) Pd–O bond lengths. P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.50–1.64 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three K1+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two K1+ and two equivalent P5+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Pd2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent K1+, one Pd2+, and one P5+ atom.

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