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At least 1,261 records · Page 70
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Electrochemical production of H 2 O 2 on palladium-based clusters driven by metal–support interaction

Utilizing palladium (Pd) clusters as active sites offers a promising route to minimize noble metal consumption in electrochemical hydrogen peroxide (H 2 O 2 ) production. In this work, we present a synthesis approach for anchoring Pd-based clusters onto carbon-supported CeO 2 nanosubstrates to enable efficient H 2 O 2 generation via the two-electron oxygen reduction reaction (ORR) pathway. By systematically adjusting Pd loading, we evaluated its impact on H 2 O 2 yield and production rate. The catalyst with the lowest Pd content (0.027 wt%) exhibited outstanding performance, achieving 97% H 2 O 2 selectivity, 94.2 faradaic efficiency at 0.7 V vs. RHE, and a peak production rate of 195.8 mol g Pd −1 h −1 . A formulation containing 0.35 wt% Pd delivered a peak ORR mass activity nearly three times as high as that of commercial 10 wt% Pd/C, while retaining comparable electrochemical stability. These enhancements are attributed to synergistic effects among isolated PdO clusters, CeO 2 nanocrystals, and the conductive carbon support, which together facilitate oxygen adsorption and promote the two-electron ORR pathway. Analysis after accelerated durability testing further revealed a tendency toward cluster agglomeration and mass transfer from smaller to larger nanocrystals, indicative of a coarsening mechanism. Overall, this study underscores the promise of low-Pd PdO–CeO 2 –carbon hybrid catalysts for scalable and efficient H 2 O 2 electrosynthesis, while highlighting stability as a critical area for future improvement.

36 MATERIALS SCIENCE↗
DOE OSTI2022

First Application of Mass Measurements with the Rare-RI Ring Reveals the Solar r -Process Abundance Trend at A = 122 and A = 123

The Rare-RI Ring (R3) is a recently commissioned cyclotronlike storage ring mass spectrometer dedicated to mass measurements of exotic nuclei far from stability at Radioactive Isotope Beam Factory (RIBF) in RIKEN. The first application of mass measurement using the R3 mass spectrometer at RIBF is reported. Rare isotopes produced at RIBF— 127 Sn, 126 In, 125 Cd, 124 Ag, 123 Pd—were injected in R3. Masses of 126 In, 125 Cd, and 123 Pd were measured whereby the mass uncertainty of 123 Pd was improved. This is the first reported measurement with a new storage ring mass spectrometry technique realized at a heavy-ion cyclotron and employing individual injection of the preidentified rare nuclei. The latter is essential for the future mass measurements of the rarest isotopes produced at RIBF. The impact of the new 123 Pd result on the solar r-process abundances in a neutron star merger event is investigated by performing reaction network calculations of 20 trajectories with varying electron fraction Y e . It is found that the neutron capture cross section on 123 Pd increases by a factor of 2.2 and β-delayed neutron emission probability, P 1n , of 123 Rh increases by 14%. The neutron capture cross section on 122 Pd decreases by a factor of 2.6 leading to pileup of material at A = 122, thus reproducing the trend of the solar r-process abundances. The trend of the two-neutron separation energies (S 2n ) was investigated for the Pd isotopic chain. The new mass measurement with improved uncertainty excludes large changes of the S 2n value at N = 77. Finally, such large increase of the S 2n values before N = 82 was proposed as an alternative to the quenching of the N = 82 shell gap to reproduce r-process abundances in the mass region of A = 112 – 124.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

A free association semantic task for fNIRS-based perinatal depression assessment

Perinatal depression (PD) is a highly prevalent psychological disorder that has a detrimental effect on infant and maternal physical and mental health, but effective and objective assessment of PD is still insufficient. In recent years, the functional near-infrared spectroscopy (fNIRS) has been acknowledged as an effective non-invasive tool for clinical assessment of depression. This study proposed a free association semantic task (FAST) paradigm for fNIRS-based assessment of PD. To better address the emotion characteristics of PD, the participants are required to generate a dynamic concept chain based on positive, negative or neutral seed words, while 48-channel fNIRS recordings over frontal and bilateral temporal regions. Results from twenty-two late-pregnant women revealed that, the oxyhemoglobin (oxy-Hb) changes during the FAST with the positive and negative seed words over the frontal region were correlated with PD severity, which was different from the correlation patterns in the FAST with neutral seed word and the classical verbal fluency test (VFT). Furthermore, distinct correlation patterns were also observed in the FAST with the positive and negative seed words, manifested in fNIRS channels corresponding to the right dorsolateral prefrontal cortex (DLPFC) and right inferior frontal gyrus (IFG), respectively. Moreover, regression analyses showed that the FAST with positive and negative seed words can well explain the severity of PD. Our findings suggest the proposed FAST paradigm as a promising approach for PD assessment.

Chen, Danni↗
NASA NTRS1992

Dietary protein deficiency reduces lysosomal and nonlysosomal ATP-dependent proteolysis in muscle

When rats are fed a protein deficient (PD) diet for 7 days, rates of proteolysis in skeletal muscle decrease by 40-50% (N. E. Tawa, Jr., and A. L. Goldberg. Am. J. Physiol. 263 (Endocrinol. Metab. 26): E317-325, 1992). To identify the underlying biochemical adaptations, we measured different proteolytic processes in incubated muscles. The capacity for intralysosomal proteolysis, as shown by sensitivity to methylamine or lysosomal protease inhibitors, fell 55-75% in muscles from PD rats. Furthermore, extracts of muscles of PD rats showed 30-70% lower activity of many lysosomal proteases, including cathepsins B, H, and C, and carboxypeptidases A and C, as well as other lysosomal hydrolases. The fall in cathepsin B and proteolysis was evident by 3 days on the PD diet, and both returned to control levels 3 days after refeeding of the normal diet. In muscles maintained under optimal conditions, 80-90% of protein breakdown occurs by nonlysosomal pathways. In muscles of PD rats, this ATP-dependent process was also 40-60% slower. Even though overall proteolysis decreased in muscles of PD rats, their capacity for Ca(2+)-dependent proteolysis increased (by 66%), as did the activity of the calpains (+150-250%). Thus the lysosomal and the ATP-dependent processes decrease coordinately and contribute to the fall in muscle proteolysis in PD animals.

Non-NASA Center↗
NASA NTRS2005

The Palladium Isotopic Composition in Iron Meteorites

Ru, Mo and Pd are very useful indicators for the identification of nucleosynthetic components. We have developed techniques for Pd isotopes, in an effort to check the extent of isotopic effects in this mass region and for a Pt-group element which is less refractory than Ru. Stable Pd isotopes are produced by the process only (102Pd), the s-process only (104Pd), the process only (Pd-110) and by both the r- and s-processes (Pd-105, Pd-106, Pd-108). Kelly and Wasserburg reported a hint of a shift in 102Pd (approx. 25(epsilon)u; 1(epsilon)u (triple bonds) 0.01%) in Santa Clara. Earlier searches for Mo and Ru isotopic anomalies were either positive or negative.

Chen, J. H.↗
DOE OSTI2023

Silver-decorated palladium on carbon catalyst for enhanced ammonium formate dehydrogenation

Palladium (Pd)-based catalysts efficiently convert ammonium formate solution to hydrogen at low temperatures (<100 °C), but they tend to deactivate quickly during stability testing. This manuscript presents a systematic investigation into the catalytic properties of Pd–Ag bimetallic catalysts, focusing on their surface compositions and exploring the mechanisms behind the deactivation of Pd/Ag-based catalysts. Here this study reports a carbon-supported Pd–Ag bimetallic nanoparticle (NP) catalyst obtained through a galvanic replacement method, which showed enhanced formate dehydrogenation performance. The best catalyst, Pd 3 Ag 10 /ACA-G (Pd–Ag bimetallic NPs with a 3 : 10 mass ratio loaded on acid-washed activated carbon, prepared by the galvanic replacement method), presents the highest activity with a TOF of 5202 h -1 (~2.6-fold of commercial Pd/C). The enhanced electron density of Pd–Ag bimetallic nanoparticles, coupled with the advantages of a smaller nanoparticle size, and the modulation of hydrogen adsorption energy through the Ag/Pd surface alloy on the Ag/Pd(111) facet, collectively resulted in experimentally higher turnover rates of hydrogen production. The changes on the catalyst surface, including surface Ag fraction decrease, NP size growth, and O-containing species (carboxylate, etc.) adsorption, gradually resulted in catalyst deactivation.

08 HYDROGEN↗
DOE OSTI2020

Materials Data on Yb3(GePd)4 by Materials Project

Yb3Pd4Ge4 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. there are two inequivalent Yb sites. In the first Yb site, Yb is bonded to six Ge atoms to form distorted edge-sharing YbGe6 octahedra. There are two shorter (3.07 Å) and four longer (3.12 Å) Yb–Ge bond lengths. In the second Yb site, Yb is bonded in a 12-coordinate geometry to six equivalent Pd and six Ge atoms. There are four shorter (3.08 Å) and two longer (3.11 Å) Yb–Pd bond lengths. There are two shorter (2.98 Å) and four longer (3.02 Å) Yb–Ge bond lengths. Pd is bonded in a 12-coordinate geometry to three equivalent Yb and four Ge atoms. There are a spread of Pd–Ge bond distances ranging from 2.59–2.62 Å. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to six Yb, two equivalent Pd, and one Ge atom. The Ge–Ge bond length is 2.55 Å. In the second Ge site, Ge is bonded in a 9-coordinate geometry to three Yb and six equivalent Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaSn3Pd by Materials Project

BaPdSn3 crystallizes in the tetragonal I4mm space group. The structure is three-dimensional. Ba is bonded in a 12-coordinate geometry to five equivalent Pd and twelve Sn atoms. There are four shorter (3.90 Å) and one longer (3.99 Å) Ba–Pd bond lengths. There are a spread of Ba–Sn bond distances ranging from 3.65–3.78 Å. Pd is bonded in a 5-coordinate geometry to five equivalent Ba and five Sn atoms. There are one shorter (2.69 Å) and four longer (2.74 Å) Pd–Sn bond lengths. There are two inequivalent Sn sites. In the first Sn site, Sn is bonded in a 2-coordinate geometry to four equivalent Ba, two equivalent Pd, and two equivalent Sn atoms. Both Sn–Sn bond lengths are 3.10 Å. In the second Sn site, Sn is bonded in a 1-coordinate geometry to four equivalent Ba, one Pd, and four equivalent Sn atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th2Pd by Materials Project

Th2Pd is Khatyrkite structured and crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. Th is bonded in a 4-coordinate geometry to four equivalent Pd atoms. All Th–Pd bond lengths are 3.13 Å. Pd is bonded in a 10-coordinate geometry to eight equivalent Th and two equivalent Pd atoms. Both Pd–Pd bond lengths are 2.98 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on VPd2 by Materials Project

VPd2 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. V is bonded to two equivalent V and ten equivalent Pd atoms to form distorted VV2Pd10 cuboctahedra that share corners with two equivalent VV2Pd10 cuboctahedra, corners with ten equivalent PdV5Pd7 cuboctahedra, edges with twelve equivalent VV2Pd10 cuboctahedra, edges with twelve equivalent PdV5Pd7 cuboctahedra, faces with four equivalent VV2Pd10 cuboctahedra, and faces with fourteen equivalent PdV5Pd7 cuboctahedra. Both V–V bond lengths are 2.75 Å. There are eight shorter (2.71 Å) and two longer (2.82 Å) V–Pd bond lengths. Pd is bonded to five equivalent V and seven equivalent Pd atoms to form distorted PdV5Pd7 cuboctahedra that share corners with five equivalent VV2Pd10 cuboctahedra, corners with seven equivalent PdV5Pd7 cuboctahedra, edges with six equivalent VV2Pd10 cuboctahedra, edges with eighteen equivalent PdV5Pd7 cuboctahedra, faces with seven equivalent VV2Pd10 cuboctahedra, and faces with eleven equivalent PdV5Pd7 cuboctahedra. There are a spread of Pd–Pd bond distances ranging from 2.70–2.77 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SrPd2 by Materials Project

Pd2Sr is Cubic Laves structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Sr is bonded in a 12-coordinate geometry to twelve equivalent Pd atoms. All Sr–Pd bond lengths are 3.29 Å. Pd is bonded to six equivalent Sr and six equivalent Pd atoms to form a mixture of face, edge, and corner-sharing PdSr6Pd6 cuboctahedra. All Pd–Pd bond lengths are 2.81 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiGePd by Materials Project

TiPdGe crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Ti is bonded in a 11-coordinate geometry to six equivalent Pd and five Ge atoms. There are two shorter (2.88 Å) and four longer (3.04 Å) Ti–Pd bond lengths. All Ti–Ge bond lengths are 2.74 Å. Pd is bonded in a 10-coordinate geometry to six equivalent Ti and four Ge atoms. There are two shorter (2.50 Å) and two longer (2.54 Å) Pd–Ge bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to six equivalent Ti and three equivalent Pd atoms. In the second Ge site, Ge is bonded in a 9-coordinate geometry to three equivalent Ti and six equivalent Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaPd2 by Materials Project

BaPd2 is Cubic Laves structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Ba is bonded in a 12-coordinate geometry to twelve equivalent Pd atoms. All Ba–Pd bond lengths are 3.37 Å. Pd is bonded to six equivalent Ba and six equivalent Pd atoms to form a mixture of edge, face, and corner-sharing PdBa6Pd6 cuboctahedra. All Pd–Pd bond lengths are 2.88 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on EuPd2 by Materials Project

EuPd2 is Cubic Laves structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Eu is bonded in a 12-coordinate geometry to twelve equivalent Pd atoms. All Eu–Pd bond lengths are 3.25 Å. Pd is bonded to six equivalent Eu and six equivalent Pd atoms to form a mixture of edge, face, and corner-sharing PdEu6Pd6 cuboctahedra. All Pd–Pd bond lengths are 2.77 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SrIn4Pd by Materials Project

SrPdIn4 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Sr is bonded in a 1-coordinate geometry to two equivalent Pd and thirteen In atoms. Both Sr–Pd bond lengths are 3.49 Å. There are a spread of Sr–In bond distances ranging from 3.36–3.93 Å. Pd is bonded in a 9-coordinate geometry to two equivalent Sr and seven In atoms. There are a spread of Pd–In bond distances ranging from 2.70–2.86 Å. There are three inequivalent In sites. In the first In site, In is bonded in a 3-coordinate geometry to three equivalent Sr, three equivalent Pd, and one In atom. The In–In bond length is 3.23 Å. In the second In site, In is bonded in a distorted q6 geometry to four equivalent Sr and six In atoms. All In–In bond lengths are 3.24 Å. In the third In site, In is bonded in a 2-coordinate geometry to three equivalent Sr, one Pd, and four equivalent In atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaIn4Pd by Materials Project

CaPdIn4 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Ca is bonded in a 7-coordinate geometry to two equivalent Pd and eleven In atoms. Both Ca–Pd bond lengths are 3.34 Å. There are a spread of Ca–In bond distances ranging from 3.27–3.66 Å. Pd is bonded in a 9-coordinate geometry to two equivalent Ca and seven In atoms. There are a spread of Pd–In bond distances ranging from 2.74–2.83 Å. There are three inequivalent In sites. In the first In site, In is bonded in a 3-coordinate geometry to three equivalent Ca, three equivalent Pd, and one In atom. The In–In bond length is 3.11 Å. In the second In site, In is bonded in a distorted linear geometry to one Ca, one Pd, and four equivalent In atoms. All In–In bond lengths are 3.16 Å. In the third In site, In is bonded in a distorted q6 geometry to four equivalent Ca and six In atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PdPb2 by Materials Project

Pb2Pd is Khatyrkite structured and crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. Pd is bonded in a 10-coordinate geometry to two equivalent Pd and eight equivalent Pb atoms. Both Pd–Pd bond lengths are 2.96 Å. All Pd–Pb bond lengths are 3.02 Å. Pb is bonded in a 7-coordinate geometry to four equivalent Pd and three equivalent Pb atoms. There are one shorter (3.25 Å) and two longer (3.43 Å) Pb–Pb bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pd3Pb by Materials Project

Pd3Pb is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Pd is bonded to eight equivalent Pd and four equivalent Pb atoms to form PdPd8Pb4 cuboctahedra that share corners with twelve equivalent PdPd8Pb4 cuboctahedra, edges with eight equivalent PbPd12 cuboctahedra, edges with sixteen equivalent PdPd8Pb4 cuboctahedra, faces with four equivalent PbPd12 cuboctahedra, and faces with fourteen equivalent PdPd8Pb4 cuboctahedra. All Pd–Pd bond lengths are 2.91 Å. All Pd–Pb bond lengths are 2.91 Å. Pb is bonded to twelve equivalent Pd atoms to form PbPd12 cuboctahedra that share corners with twelve equivalent PbPd12 cuboctahedra, edges with twenty-four equivalent PdPd8Pb4 cuboctahedra, faces with six equivalent PbPd12 cuboctahedra, and faces with twelve equivalent PdPd8Pb4 cuboctahedra.

36 MATERIALS SCIENCE↗