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In situ Gas-Cell Electron Microscopy Reveals Pressure-Selected Restructuring Pathways in AuRu Ammonia Catalysts

T0 review · 3 major / 5 minor · reviewed 2026-08-03 · deepseek-v4-flash

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Pith's one-line read Atmospheric-pressure hydrogen redirects AuRu ammonia catalysts from thermal phase segregation into a faceting-and-nanovoid restructuring regime via a gas-mediated Kirkendall effect.

desk verdict Solid in-situ gas-cell study where the faceting result holds up; the void-formation population claim needs more statistics than 1/14 and an unsourced 5–10%. read the letter →

arxiv 2602.00433 v2 pith:SSFG4FO5 submitted 2026-01-31 cond-mat.mtrl-sci

Amy S. McKeown-Green , Parivash Moradifar , Zisheng Zhang , Cedric Lim , Andrew Barnum , Lin Yuan , Robert Sinclair , Frank Abild-Pedersen
show 2 more authors
Colin Ophus Jennifer A. Dionne
This is my paper · ORCID
classification cond-mat.mtrl-sci
keywords insituelectronmicroscopygas-cellAuRubimetallicammoniasynthesisnanovoidformationKirkendalleffecthydrogenadsorptionphasesegregation
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This paper sets out to show that restructuring in AuRu ammonia-synthesis catalysts is selected not only by temperature but also by gas pressure and chemistry, and that atmospheric-pressure H2:N2 opens a pathway invisible at the lower pressures typical of in situ electron microscopy. Using gas-cell imaging with correlative spectroscopy and tomography, it documents that at roughly one atmosphere the particles develop sharp facets and internal nanovoids, and that pure hydrogen, not inert gas or nitrogen, drives the effect. The proposed mechanism is a hydrogen-mediated Kirkendall effect: adsorbed H amplifies the Au/Ru diffusivity mismatch, causing vacancies to accumulate at internal Au/Ru interfaces and coalesce into voids. A sympathetic reader would care because this closes a pressure gap between laboratory imaging and real catalytic reactors, and it identifies hydrogen pressure as a controllable handle on nanoscale morphology.

What carries the argument

The load-bearing mechanism is the gas-mediated Kirkendall effect: after thermal phase segregation creates internal Au/Ru interfaces, adsorbed hydrogen changes the relative diffusion rates of Au and Ru so that more Au moves into Ru than Ru into Au, injecting vacancies that cluster into nanovoids. The supporting machinery is a multimodal in situ gas-cell scanning transmission electron microscopy workflow—HAADF imaging through SiN membranes, X-EDS elemental mapping, monochromated EELS plasmon mapping, 4D-STEM phase/orientation mapping, and machine-learning-assisted electron tomography—plus DFT-trained machine-learning interatomic potentials and grand-canonical Monte Carlo simulations to compute

What would settle it

Track a statistically meaningful set of AuRu particles—say 50 or more—under 782 Torr H2:N2 and count the nanovoid fraction; if the rate is comparable to the 1-in-14 observed in situ and shows no dependence on H2 partial pressure, the claim of a distinct pressure-selected regime collapses.

Watch

Extended reading notes

Core claim

The central claim is that pressure and gas chemistry select among distinct restructuring pathways in AuRu nanocrystals, and that atmospheric-pressure H2:N2 unlocks a regime absent at lower pressures: pronounced faceting and internal nanovoid formation. Gas-chemistry control experiments show the effect is hydrogen-specific, and DFT-trained machine-learning interatomic potentials support a gas-mediated Kirkendall mechanism in which adsorbed H changes the Au/Ru diffusion barriers from 0.41/0.23 eV to 0.87/0.18 eV, amplifying the diffusivity mismatch so vacancies cluster into voids. The paper offers this as the first in situ demonstration that hydrogen pressure can regulate vacancy-mediated nano

Load-bearing premise

The load-bearing premise is that the single in situ particle (1 of 14) that formed a nanovoid, plus the 5-10% rate estimated from post-characterization, represents a genuine pressure-selected pathway rather than a rare anomaly; the paper itself notes the low in situ count.

Editorial extensions

If this is right

  • Realistic atmospheric-pressure operation of AuRu ammonia catalysts produces a morphological state—faceted particles with internal nanovoids—that low-pressure and vacuum in situ studies cannot capture, so assessments of catalyst stability based on low-pressure observations will miss the active or aged structure.
  • Hydrogen partial pressure becomes a control parameter: switching from Ar or N2 to H2 at the same ~1 atm pressure turns on void formation, giving catalyst designers a chemically addressable handle on nanoscale morphology.
  • Nanovoids nucleate at Au/Ru interfaces after phase segregation, locating the structural damage in the catalytically active Ru-rich regions rather than at the free surface.
  • The computed diffusion-barrier changes under hydrogen supply a quantitative route to predicting conditions that either avoid or exploit Kirkendall voiding in bimetallic nanoparticles.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • If the hydrogen-mediated Kirkendall effect is general, then other strongly adsorbing gases—CO, O2, NH3—could similarly bias interdiffusion in bimetallic nanoparticles, making vacancy engineering a gas-selected rather than temperature-selected process.
  • The 1-of-14 in situ rate suggests nanovoid formation is stochastic and particle-dependent; a population-level in situ survey correlating void probability with particle size, twin density, and grain-boundary structure could test whether the 5-10% post-reaction fraction is tunable.
  • The paper's observation that extended oxygen-plasma cleaning produced voids at lower H2 pressure implies that surface defect density lowers the void-formation threshold; intentional defect seeding could test this and explain particle-to-particle variability.
  • Because phase segregation relocalizes the plasmonic response, void formation may also change optical properties; monitoring Au and Ru plasmon maps during void growth could give an optical signature of catalyst degradation.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

3 major / 5 minor

Summary. The paper uses in situ gas-cell STEM combined with X-EDS, EELS, 4D-STEM, and ML-accelerated tomography to track restructuring of AuRu bimetallic nanocatalysts under H2:N2 environments up to 1 atm. It reports that vacuum annealing induces Au/Ru phase segregation into Au FCC and Ru HCP domains, while atmospheric-pressure H2:N2 (3:1) additionally produces pronounced faceting and, in a minority of particles, internal nanovoids. Gas-switching experiments identify H2 as the chemical driver, and DFT-trained MLIP plus GCMC simulations suggest a gas-mediated Kirkendall mechanism in which adsorbed H increases the Au/Ru diffusivity mismatch. The paper claims this constitutes a distinct pressure-selected restructuring pathway absent at lower pressures.

Significance. If the central claim holds, the work is significant: it demonstrates a gas-pressure-dependent restructuring regime in a working catalytic nanomaterial, with multimodal evidence including single-particle X-EDS and 3D tomography, and it proposes a conceptually new variant of the Kirkendall effect. The experimental platform closes a real pressure gap in TEM studies of ammonia catalysis. Strengths include the careful correlative characterization, the confirmation of the nanovoid by X-EDS and tomography, the use of DFT-trained MLIP barriers that are not fitted to the observed voids, and the reproducible faceting behavior shown for multiple particles in Figs. S13–S15. The main weakness is the population-level evidence for nanovoid formation, which is central to the 'pressure-selected regime' claim.

major comments (3)
  1. [Fig. 4C paragraph and Figs. S11–S12] The central claim that 782 Torr H2:N2 unlocks a distinct void-forming regime rests on 1 of 14 in-situ particles and a post-reaction estimate of 'roughly 5–10% of particles outside the viewing window.' The text does not state whether the 14 particles are all at 782 Torr or distributed across 50/350/782 Torr; if the latter, the 782 Torr denominator could be only 2–5. The 5–10% estimate is presented without a denominator or selection criterion, and Figs. S11–S12 show selected voided particles rather than a systematic montage or count. A binomial 95% CI for 1/14 is approximately 0–34%, so the data cannot distinguish a genuine 5–10% pathway from a rare anomaly. This is load-bearing because the 'pressure-selected restructuring pathway' in the title and abstract depends on nanovoid formation being a population behavior, not an outlier. Please provide per-pressure denominators, a systematic post
  2. [Fig. 5C and 'Hydrogen activates nanovoid formation' section] The pure-H2 experiments are described qualitatively as 'many nanocrystals showing nanovoid formation' without a denominator or a quantitative comparison to the H2:N2 rate. Since the in-situ H2:N2 case is n=1, the claim that H2 is the dominant driver and that the threshold is H2 partial pressure ≥0.75 atm needs a systematic survey. In addition, Fig. S11(C–F) reports nanovoid formation at 350 Torr after extended O2 plasma cleaning, which the authors attribute to introduced vacancies/defects. This shows that preparation-induced defects can substitute for pressure, raising a confound for the pressure-selected interpretation. Please quantify the plasma-cleaning effect and, at minimum, state how the 60-s cleaning protocol was controlled across the pressure series.
  3. [MLIP/GCMC paragraph in 'Hydrogen activates nanovoid formation'] The gas-mediated Kirkendall mechanism is inferred from two diffusion barriers: Au-in-Ru 0.41→0.87 eV and Ru-in-Au 0.23→0.18 eV. While the asymmetry ratio increases, a net vacancy flux and void nucleation depend on prefactors, vacancy formation energies, and the interdiffusion geometry; the paper does not provide a kinetic model connecting these barriers to vacancy supersaturation. The GCMC simulation shows H on Ru surfaces and some subsurface H, but it does not compute vacancy concentrations or void nucleation. The mechanism is plausible, but as presented it is a hypothesis consistent with the data rather than a demonstrated pathway. Please add a quantitative vacancy-flux or kinetic Monte Carlo model, or revise the mechanistic claim to reflect the level of support.
minor comments (5)
  1. [Abstract] Typo: 'absorbed H atoms' should be 'adsorbed H atoms'.
  2. [Throughout] Notation for the gas mixture is inconsistent (H2:N2 vs H₂:N₂); please unify.
  3. [Fig. 4D–F] The particle-size changes are reported for single particles. Please specify whether the error bars reflect Otsu thresholding uncertainty or particle-to-particle variance, and indicate how many particles were averaged.
  4. [Fig. S11] The O2 plasma-cleaning explanation for voids at 350 Torr is stated categorically. A control with matched cleaning time and gas composition would make this statement rigorous.
  5. [References] The SI reference list includes the Yuan et al. work both as an arXiv preprint and as the published Nat. Energy article (ref 17 in main text); unify to avoid duplicate citation.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the mechanistic barriers and GCMC hydrogen chemical potentials are independent outputs, not fitted values.

full rationale

The paper's claimed derivation — H2 pressure/chemistry → H adsorption → modified Au/Ru diffusion barriers → enhanced Kirkendall-type vacancy accumulation → nanovoids — is not circular by construction. The key quantitative inputs (0.41 eV for Au-in-Ru and 0.23 eV for Ru-in-Au without H; 0.87 eV and 0.18 eV with H) are obtained from nudged-elastic-band calculations on a DFT-trained MLIP; the MLIP is trained on GCGO/DFT energies and forces, not on the experimental nanovoid observations, so the barriers are not fitted to reproduce the voids. The GCMC simulation sets the H chemical potential from the experimental H2 pressure via μH = 1/2[G(H2,g) + kBT ln(p/p°)] and outputs H coverage; it does not presuppose void formation. The hydrogen driver is constrained experimentally by Ar/N2/H2 comparisons and by the external pure-Au control (ref. 43). The paper's own admission that only 1 of 14 in-situ particles formed a void, with a 'roughly 5–10%' post-characterization estimate lacking a stated denominator, is a legitimate evidence-strength weakness, but underpowered statistics is not circularity. Self-citations (synthesis/context Yuan et al.; tomography Lim et al.) are methods/background and are not load-bearing for the central mechanistic claim. No equation reduces the prediction to an input.

Assumptions & free parameters 0 free parameters · 5 assumptions · 0 invented entities

The central claim rests primarily on experimental observations plus computed barrier changes. No new physical entities are introduced. The main assumptions are methodological: DFT/MLIP fidelity, void identification, transferability of the Kirkendall picture to gas-exposed interfaces, and representative particle statistics.

assumptions (5)
  • domain assumption PBEsol+D3 DFT accurately describes Au/Ru/H adsorption and diffusion energetics
    The MLIP training data and final barriers inherit the accuracy of the DFT functional; systematic errors in adsorption energies would shift the computed diffusion barriers and the H-coverage from GCMC.
  • domain assumption The fine-tuned MACE-MP-0 MLIP generalizes to large-scale interface/vacancy configurations not explicitly used in training
    Parity plots (Fig. S22) validate energies and forces on a held-out test set, but the NEB barrier heights for the specific Au/Ru interface paths are not cross-validated against direct DFT calculations.
  • domain assumption The nanoscale Kirkendall mechanism (unequal diffusivities → vacancy flux → void nucleation) applies in this polycrystalline, gas-exposed nanoparticle
    The paper adopts the classical Kirkendall framework to interpret the barrier asymmetry; its applicability to gas-exposed, internally interfaced nanoparticles is assumed, not directly demonstrated in the simulations.
  • domain assumption Absence of Au and Ru X-ray signals in the dark-contrast central region indicates a true void rather than a shadowing, thickness, or detection artifact
    Void identification depends on X-EDS signal absence and on machine-learning-assisted tomography with a ±40° missing wedge; residual uncertainty remains about whether all 'voids' are genuinely empty rather than low-density regions.
  • domain assumption The gas cell maintains the nominal H2:N2 composition at pressure without significant beam-induced chemistry changes
    The paper uses Ar as a radiolysis control, but continuous electron irradiation of the gas may generate reactive species; the control supports the assumption but does not eliminate the need for it.

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Pith. "Pith review of In situ Gas-Cell Electron Microscopy Reveals Pressure-Selected Restructuring Pathways in AuRu Ammonia Catalysts." pith.science (2026). https://pith.science/paper/SSFG4FO5

@misc{pith2026260200433,
  author       = {Pith},
  title        = {Pith review of: In situ Gas-Cell Electron Microscopy Reveals Pressure-Selected Restructuring Pathways in AuRu Ammonia Catalysts},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/SSFG4FO5}},
  note         = {Machine review of arXiv:2602.00433}
}
abstract

Bimetallic catalysts provide new routes toward sustainable ammonia synthesis, but the nanoscale structural dynamics under reaction-relevant conditions remain poorly understood. Here, we combine in situ gas-cell and multimodal electron microscopy to determine how temperature, gas pressure, and chemistry select among distinct restructuring pathways in AuRu nanocrystal catalysts. Initially, the AuRu nanocrystals form polycrystalline face-centered cubic (FCC) alloys with Au/Ru intermixing. Elevated temperature ($\geq 350~^\circ$C) induces intraparticle phase segregation into distinct Au-rich (FCC) and Ru-rich hexagonal close-packed (HCP) domains that exhibit localized plasmonic modes. Atmospheric-pressure 3:1 H$_2$:N$_2$ gas unlocks a distinct restructuring regime absent at lower pressures, characterized by pronounced faceting and nanovoid formation. Systematic gas variation identifies hydrogen as the dominant driver. Density functional theory-trained machine-learning interatomic potentials and grand-canonical Monte Carlo simulations reveal that H-Ru interactions enhance the Au/Ru diffusivity mismatch, promoting vacancy accumulation and nanovoid formation. Together, these results show that, rather than simply accelerating the thermally driven phase segregation observed at lower pressures, atmospheric-pressure H$_2$:N$_2$ gas redirects restructuring toward faceting and nanovoid formation through a gas-mediated Kirkendall-type mechanism.

Figures

Figures reproduced from arXiv: 2602.00433 by the authors.

Figure 1
Figure 1. Multi-modal characterization of pristine AuRu nanocatalysts prior to thermal annealing or gas-phase catalysis. (A) Schematic of the experimental setup showing the high-pressure gas-cell integrated [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
Figure 2
Figure 2. Vacuum annealing induced Au–Ru phase segregation. (A) STEM-HAADF image series of three representative AuRu nanocrystals of increasing size during stepwise heating from room temperature (RT) to 750 °C at a 20 °C/min ramp rate with 10-min holds at each temperature. Progressive Au–Ru phase segregation is denoted by two regions of distinct Z-contrast (Au - light, Ru - dark), indicated by white arrows. (B) X-EDS elementa… view at source ↗
Figure 3
Figure 3. Crystallographic phase segregation and plasmonic reconfiguration in Au [PITH_FULL_IMAGE:figures/full_fig_p008_3.png] view at source ↗
Figures from the paper (2 more)
Figure 4
Figure 4. Figure 4: In situ gas-cell imaging of pressure-dependent restructuring in AuRu nanocatalysts in a H2:N2 (3:1) gas environment. (A-C) STEM-HAADF sequences of three representative Au–Ru nanocrystals acquired during stepwise heating to 750 °C in 100 °C increments in a H2:N2 (3:1) g…
Figure 5
Figure 5. Figure 5: Hydrogen drives nanovoid nucleation in Au [PITH_FULL_IMAGE:figures/full_fig_p013_5.png]

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Works this paper leans on

69 extracted references · 2 canonical work pages

  1. [1]

    J. W. Erisman, M. A. Sutton, J. Galloway, Z. Klimont, W. Winiwarter, How a century of ammonia synthesis changed the world. Nat. Geosci. 1, 636–639 (2008)

    2008

  2. [2]

    Vojvodic, A

    A. Vojvodic, A. J. Medford, F. Studt, F. Abild-Pedersen, T. S. Khan, T. Bligaard, J. K. Nørskov, Exploring the limits: A low-pressure, low-temperature Haber–Bosch process. Chem. Phys. Lett. 598, 108–112 (2014)

    2014

  3. [3]

    Y. Gao, A. Cabrera Serrenho, Greenhouse gas emissions from nitrogen fertilizers could be reduced by up to one-fifth of current levels by 2050 with combined interventions. Nat. Food 4, 170–178 (2023)

  4. [4]

    Xue, S.-N

    Z.-H. Xue, S.-N. Zhang, Y.-X. Lin, H. Su, G.-Y. Zhai, J.-T. Han, Q.-Y. Yu, X.-H. Li, M. Antonietti, J.-S. Chen, Electrochemical reduction of N2 into NH3 by donor-acceptor couples of Ni and Au nanoparticles with a 67.8% Faradaic efficiency. J. Am. Chem. Soc. 141, 14976–14980 (2019)

    2019

  5. [5]

    M. Sun, C. Ma, M. Ma, Y. Wei, S. Dong, X. Zhang, J. Tian, M. Shao, Electrochemical ammonia synthesis via nitrogen reduction reaction on 1T/2H mixed-phase MoSSe catalyst: Theoretical and experimental studies. Mater. Today Phys. 30, 100945 (2023)

    2023

  6. [6]

    Mu, X.-W

    J. Mu, X.-W. Gao, T. Yu, L.-K. Zhao, W.-B. Luo, H. Yang, Z.-M. Liu, Z. Sun, Q.-F. Gu, F. Li, Ambient electrochemical ammonia synthesis: From theoretical guidance to catalyst design. Adv. Sci. (Weinh.) 11, e2308979 (2024)

    2024

  7. [7]

    Hattori, N

    M. Hattori, N. Okuyama, H. Kurosawa, M. Hara, Low-temperature ammonia synthesis on iron catalyst with an electron donor. J. Am. Chem. Soc. 145, 7888–7897 (2023)

    2023

  8. [8]

    J. Wang, L. Liu, R. Li, S. Wang, X. Ju, T. He, J. Guo, P. Chen, Highly active manganese nitride-europium nitride catalyst for ammonia synthesis. iScience 27, 110858 (2024)

    2024

Show all 69 references
  1. [9]

    F. Tian, J. Li, W. Chen, L. Tang, M. Wu, Innovative progress of thermal ammonia synthesis under mild conditions. Int. J. Hydrogen Energy 78, 92–122 (2024)

    2024

  2. [10]

    Arjones-Fernández, A

    B. Arjones-Fernández, A. Malik, L. Guillade, R. Khatua, L. V. Besteiro, A. Sousa-Castillo, M. Vázquez-González, R. A. Álvarez-Puebla, M. A. Correa-Duarte, Solar‐driven Photocatalytic N 2 reduction to ammonia using plasmonic Au@NiZIF‐8 MOF hybrids. Adv. Opt. Mater., doi: 10.100...

    2025 doi

  3. [11]

    Moriya, Converting N2 molecules into NH3 with TiO2/Fe3O4 composite covered with a thin water layer under ambient condition

    I. Moriya, Converting N2 molecules into NH3 with TiO2/Fe3O4 composite covered with a thin water layer under ambient condition. Sci. Rep. 13, 7746 (2023)

    2023

  4. [12]

    Y. Shi, Z. Zhao, D. Yang, J. Tan, X. Xin, Y. Liu, Z. Jiang, Engineering photocatalytic ammonia synthesis. Chem. Soc. Rev. 52, 6938–6956 (2023)

    2023

  5. [13]

    L. Liu, A. Corma, Bimetallic sites for catalysis: From binuclear metal sites to bimetallic nanoclusters and nanoparticles. Chem. Rev. 123, 4855–4933 (2023)

    2023

  6. [14]

    S. S. S. Ganti, P. K. Roy, N. Wagh, K. N. S. Siva Sai, S. Kumar, Strategically designed catalysts for ammonia synthesis under mild conditions: recent advances and challenges. J. Mater. Chem. A Mater. Energy Sustain. 13, 15361–15426 (2025)

    2025

  7. [15]

    T. Hou, L. Chen, Y. Xin, W. Zhu, C. Zhang, W. Zhang, S. Liang, L. Wang, Porous CuFe for plasmon-assisted N 2 photofixation. ACS Energy Lett. 5, 2444–2451 (2020)

    2020

  8. [16]

    B.-H. Wang, B. Hu, G.-H. Chen, X. Wang, S. Tian, Y. Li, X.-S. Hu, H. Wang, C.-T. Au, L.- L. Jiang, L. Chen, S.-F. Yin, Plasmon-induced photocatalytic nitrogen fixation on medium- spin Au3Fe1/Mo single-atom alloy antenna reactor. Chem Catal. 4, 101083 (2024)

    2024

  9. [17]

    L. Yuan, B. B. Bourgeois, E. Begin, Y. Zhang, A. X. Dai, Z. Cheng, A. S. McKeown- Green, Z. Xue, Y. Cui, K. Xu, Y. Wang, M. R. Jones, Y. Cui, A. Majumdar, J. L. Bao, J. A. Dionne, Atmospheric-pressure ammonia synthesis on AuRu catalysts enabled by plasmon- controlled hydrogena...

    2025

  10. [18]

    F. Tao, M. Salmeron, Surface restructuring and predictive design of heterogeneous catalysts. Science 386 (2024)

    2024

  11. [19]

    K. D. Gilroy, A. Ruditskiy, H.-C. Peng, D. Qin, Y. Xia, Bimetallic nanocrystals: Syntheses, properties, and applications. Chem. Rev. 116, 10414–10472 (2016)

    2016

  12. [20]

    Sytwu, M

    K. Sytwu, M. Vadai, F. Hayee, D. K. Angell, A. Dai, J. Dixon, J. A. Dionne, Driving energetically unfavorable dehydrogenation dynamics with plasmonics. Science 371 , 280– 283 (2021)

    2021

  13. [21]

    J. L. Vincent, P. A. Crozier, Atomic level fluxional behavior and activity of CeO2- supported Pt catalysts for CO oxidation. Nat. Commun. 12, 5789 (2021)

    2021

  14. [22]

    K. Koo, P. J. M. Smeets, X. Hu, V. P. Dravid, Analytical in situ gas transmission electron microscopy enabled with ultrathin silicon nitride membranes. Microsc. Microanal. 29, 1597–1598 (2023)

    2023

  15. [23]

    S. B. Simonsen, S. Dahl, E. Johnson, S. Helveg, Ceria-catalyzed soot oxidation studied by environmental transmission electron microscopy. J. Catal. 255, 1–5 (2008)

    2008

  16. [24]

    S. Lee, K. Gadelrab, L. Cheng, J. P. Braaten, H. Wu, F. M. Ross, Simultaneous 2D projection and 3D topographic imaging of gas-dependent dynamics of catalytic nanoparticles. ACS Nano 18, 21258–21267 (2024)

    2024

  17. [25]

    Janbroers, P

    S. Janbroers, P. A. Crozier, H. W. Zandbergen, P. J. Kooyman, A model study on the carburization process of iron-based Fischer–Tropsch catalysts using in situ TEM–EELS. Appl. Catal. B 102, 521–527 (2011)

    2011

  18. [26]

    S. B. Vendelbo, C. F. Elkjær, H. Falsig, I. Puspitasari, P. Dona, L. Mele, B. Morana, B. J. Nelissen, R. van Rijn, J. F. Creemer, P. J. Kooyman, S. Helveg, Visualization of oscillatory behaviour of Pt nanoparticles catalysing CO oxidation. Nat. Mater. 13, 884–890 (2014)

    2014

  19. [27]

    J. Ding, L. Wang, P. Wu, A. Li, W. Li, C. Stampfl, X. Liao, B. S. Haynes, X. Han, J. Huang, Confined Ru nanocatalysts on surface to enhance ammonia synthesis: An in situ ETEM study. ChemCatChem 13, 534–538 (2021)

    2021

  20. [28]

    M. R. Ward, R. W. Mitchell, E. D. Boyes, P. L. Gai, Visualization of atomic scale reaction dynamics of supported nanocatalysts during oxidation and ammonia synthesis using in-situ environmental (scanning) transmission electron microscopy. J. Energy Chem. 57, 281–290 (2021)

    2021

  21. [29]

    Österlund, Pressure Gaps in Heterogeneous Catalysis

    L. Österlund, Pressure Gaps in Heterogeneous Catalysis. Wiley [Preprint] (2021). https://doi.org/10.1002/9783527813599.ch13

    2021 doi

  22. [30]

    Okamoto, T

    H. Okamoto, T. B. Massalski, The Au-Ru (gold-ruthenium) system. Bull. Alloy Phase Diagrams 5, 388–390 (1984)

    1984

  23. [31]

    Zhang, K

    Q. Zhang, K. Kusada, D. Wu, T. Yamamoto, T. Toriyama, S. Matsumura, S. Kawaguchi, Y. Kubota, H. Kitagawa, Selective control of fcc and hcp crystal structures in Au-Ru solid- solution alloy nanoparticles. Nat. Commun. 9, 510 (2018)

    2018

  24. [32]

    Chookajorn, H

    T. Chookajorn, H. A. Murdoch, C. A. Schuh, Design of stable nanocrystalline alloys. Science 337, 951–954 (2012)

    2012

  25. [33]

    https://next- gen.materialsproject.org/materials/mp-33

    mp-33: Ru (Hexagonal, P6_3/mmc, 194), Materials Project. https://next- gen.materialsproject.org/materials/mp-33

  26. [34]

    https://legacy.materialsproject.org/materials/mp-81/

    mp-81: Au (cubic, Fm-3m, 225). https://legacy.materialsproject.org/materials/mp-81/

  27. [35]

    Jiang, Z

    Y. Jiang, Z. M. Wong, H. Yan, T. L. Tan, U. Mirsaidov, Revealing multistep phase separation in metal alloy nanoparticles with in situ transmission electron microscopy. ACS Nano 19, 3886–3894 (2025)

    2025

  28. [36]

    S. E. Zeltmann, A. Müller, K. C. Bustillo, B. Savitzky, L. Hughes, A. M. Minor, C. Ophus, Patterned probes for high precision 4D-STEM bragg measurements. Ultramicroscopy 209, 112890 (2020)

    2020

  29. [39]

    Hébert, W.-D

    C. Hébert, W.-D. Schöne, D. S. Su, Experimental and theoretical determination of low electron energy loss spectra of Ag and Ru. Ultramicroscopy 106, 1115–1119 (2006)

    2006

  30. [40]

    Otsu, A threshold selection method from gray-level histograms

    N. Otsu, A threshold selection method from gray-level histograms. IEEE Trans. Syst. Man Cybern. 9, 62–66 (1979)

    1979

  31. [41]

    K. Koo, N. S. Chellam, S. Shim, C. A. Mirkin, G. C. Schatz, X. Hu, V. P. Dravid, Electron- induced radiation chemistry in environmental transmission electron microscopy, arXiv [cond-mat.mtrl-sci] (2024). http://arxiv.org/abs/2402.17928

    2024

  32. [43]

    Chmielewski, J

    A. Chmielewski, J. Meng, B. Zhu, Y. Gao, H. Guesmi, H. Prunier, D. Alloyeau, G. Wang, C. Louis, L. Delannoy, P. Afanasiev, C. Ricolleau, J. Nelayah, Reshaping dynamics of gold nanoparticles under H2 and O2 at atmospheric pressure. ACS Nano 13, 2024–2033 (2019)

    2024

  33. [44]

    Y. Yin, R. M. Rioux, C. K. Erdonmez, S. Hughes, G. A. Somorjai, A. P. Alivisatos, Formation of hollow nanocrystals through the nanoscale Kirkendall effect. Science 304, 711–714 (2004)

    2004

  34. [45]

    Z. Yang, N. Yang, M.-P. Pileni, Nano Kirkendall effect related to nanocrystallinity of metal nanocrystals: Influence of the outward and inward atomic diffusion on the final nanoparticle structure. J. Phys. Chem. C Nanomater. Interfaces 119, 22249–22260 (2015)

    2015

  35. [46]

    S. W. Chee, S. F. Tan, Z. Baraissov, M. Bosman, U. Mirsaidov, Direct observation of the nanoscale Kirkendall effect during galvanic replacement reactions. Nat. Commun. 8 (2017)

    2017

  36. [47]

    Carenco, C

    S. Carenco, C. Sassoye, M. Faustini, P. Eloy, D. P. Debecker, H. Bluhm, M. Salmeron, The active state of supported ruthenium oxide nanoparticles during carbon dioxide methanation. J. Phys. Chem. C Nanomater. Interfaces 120, 15354–15361 (2016)

    2016

  37. [48]

    Fraga, M

    G. Fraga, M. Konarova, L. Massin, A. D. K. Deshan, D. Rackemann, B. Laycock, S. Pratt, N. Batalha, Reduction of RuO2 nanoparticles supported on silica by organic molecules: a strategy for nanoparticle redispersion. J. Mater. Chem. A Mater. Energy Sustain. 13, 7445– 7460 (2025)

    2025

  38. [49]

    S. W. Chee, Z. M. Wong, Z. Baraissov, S. F. Tan, T. L. Tan, U. Mirsaidov, Interface- mediated Kirkendall effect and nanoscale void migration in bimetallic nanoparticles during interdiffusion. Nat. Commun. 10, 2831 (2019)

    2019

  39. [50]

    Glodán, C

    G. Glodán, C. Cserháti, I. Beszeda, D. L. Beke, Production of hollow hemisphere shells by pure Kirkendall porosity formation in Au/Ag system. Appl. Phys. Lett. 97, 113109 (2010)

    2010

  40. [51]

    Glodán, C

    G. Glodán, C. Cserháti, D. L. Beke, Temperature-dependent formation and shrinkage of hollow shells in hemispherical Ag/Pd nanoparticles. Philos. Mag. (Abingdon) 92, 3806– 3812 (2012)

    2012

  41. [52]

    El Mel, R

    A.-A. El Mel, R. Nakamura, C. Bittencourt, The Kirkendall effect and nanoscience: hollow nanospheres and nanotubes. Beilstein J. Nanotechnol. 6, 1348–1361 (2015)

    2015

  42. [53]

    B. D. Anderson, J. B. Tracy, Nanoparticle conversion chemistry: Kirkendall effect, galvanic exchange, and anion exchange. Nanoscale 6, 12195–12216 (2014)

    2014

  43. [54]

    R. B. McLellan, Solid solutions of hydrogen in gold, silver and copper. J. Phys. Chem. Solids 34, 1137–1141 (1973)

    1973

  44. [55]

    R. B. McLellan, W. A. Oates, The solubility of hydrogen in rhodium, ruthenium, iridium and nickel. Acta Metall. 21, 181–185 (1973)

    1973

  45. [56]

    M. A. Kuzovnikov, M. Tkacz, Synthesis of ruthenium hydride. Phys. Rev. B. 93 (2016)

    2016

  46. [57]

    Y. Yuan, J. Zhou, A. Bayles, H. Robatjazi, P. Nordlander, N. J. Halas, Steam methane reforming using a regenerable antenna–reactor plasmonic photocatalyst. Nat. Catal. 7, 1339–1349 (2024). Materials and Methods Nanocrystals Synthesis and Sample Preparation Bimetallic AuRu allo...

    2024

  47. [58]

    L. Yuan, B. B. Bourgeois, E. Begin, Y. Zhang, A. X. Dai, Z. Cheng, A. S. McKeown-Green, Z. Xue, Y. Cui, K. Xu, Y. Wang, M. R. Jones, Y. Cui, A. Majumdar, J. L. Bao, J. A. Dionne, Atmospheric pressure ammonia synthesis on AuRu catalysts enabled by plasmon-controlled hydrogenati...

    2024

  48. [59]

    Ophus, S

    C. Ophus, S. E. Zeltmann, A. Bruefach, A. Rakowski, B. H. Savitzky, A. M. Minor, M. C. Scott, Automated crystal orientation mapping in py4DSTEM using sparse correlation matching. Microsc. Microanal. 28, 1–14 (2022)

    2022

  49. [60]

    Zhang, W

    Z. Zhang, W. Gee, R. H. Lavroff, A. N. Alexandrova, GOCIA: a grand canonical global optimizer for clusters, interfaces, and adsorbates. Phys. Chem. Chem. Phys. 27, 696–706 (2025)

    2025

  50. [61]

    Kresse, J

    G. Kresse, J. Furthmüller, Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B Condens. Matter 54, 11169–11186 (1996)

    1996

  51. [62]

    Kresse, D

    G. Kresse, D. Joubert, From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B Condens. Matter 59, 1758–1775 (1999)

    1999

  52. [63]

    J. P. Perdew, A. Ruzsinszky, G. I. Csonka, O. A. Vydrov, G. E. Scuseria, L. A. Constantin, X. Zhou, K. Burke, Restoring the density-gradient expansion for exchange in solids and surfaces. Phys. Rev. Lett. 100, 136406 (2008)

    2008

  53. [64]

    Grimme, J

    S. Grimme, J. Antony, S. Ehrlich, H. Krieg, A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu. J. Chem. Phys. 132, 154104 (2010)

    2010

  54. [65]

    Batatia, P

    I. Batatia, P. Benner, Y. Chiang, A. M. Elena, D. P. Kovács, J. Riebesell, X. R. Advincula, M. Asta, M. Avaylon, W. J. Baldwin, F. Berger, N. Bernstein, A. Bhowmik, F. Bigi, S. M. Blau, V. Cărare, M. Ceriotti, S. Chong, J. P. Darby, S. De, F. Della Pia, V. L. Deringer, R. Elij...

    2025

  55. [66]

    Mills, H

    G. Mills, H. Jónsson, G. K. Schenter, Reversible work transition state theory: application to dissociative adsorption of hydrogen. Surf. Sci. 324, 305–337 (1995)

    1995

  56. [67]

    R. B. Wexler, T. Qiu, A. M. Rappe, Automatic prediction of surface phase diagrams using ab initio grand canonical Monte Carlo. J. Phys. Chem. C Nanomater. Interfaces 123, 2321–2328 (2019)

    2019

  57. [68]

    B. H. Savitzky, S. E. Zeltmann, L. A. Hughes, H. G. Brown, S. Zhao, P. M. Pelz, T. C. Pekin, E. S. Barnard, J. Donohue, L. Rangel DaCosta, E. Kennedy, Y. Xie, M. T. Janish, M. M. Schneider, P. Herring, C. Gopal, A. Anapolsky, R. Dhall, K. C. Bustillo, P. Ercius, M. C. Scott, J...

    2021

  58. [69]

    C. Lim, C. Casert, A. R. C. McCray, S. Lee, A. Barnum, J. Dionne, C. Ophus, Missing wedge inpainting and joint alignment in electron tomography through implicit neural representations, arXiv [eess.IV] (2025). https://doi.org/10.48550/arXiv.2512.08113

    2025 doi

  59. [70]

    A. S. McKeown-Green, J. C. Ondry, M. F. Crook, J. J. Calvin, A. P. Alivisatos, Examining the role of chloride ligands on defect removal in imperfectly attached semiconductor nanocrystals for 1D and 2D attachment cases. J. Phys. Chem. C Nanomater. Interfaces 127, 7740–7751 (2023)

    2023

  60. [71]

    J. T. Cox, G. Hass, J. B. Ramsey, W. R. Hunter, Reflectance and optical constants of evaporated ruthenium in the vacuum ultraviolet from 300 to 2000 Å. J. Opt. Soc. Am. 64, 423 (1974)

    2000

  61. [72]

    Tehuacanero-Cuapa, J

    S. Tehuacanero-Cuapa, J. Reyes-Gasga, A. Rodríguez-Gómez, D. Bahena, I. Hernández- Calderón, R. García-García, The low-loss EELS spectra from radiation damaged gold nanoparticles. J. Appl. Phys. 120, 164302 (2016)

    2016

Pith tools

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