1
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Holtz ME, Padgett E, Johnston-Peck AC, Levin I, Muller DA, Herzing AA. Mapping Polar Distortions using Nanobeam Electron Diffraction and a Cepstral Approach. Microsc Microanal 2023; 29:1422-1435. [PMID: 37488825 DOI: 10.1093/micmic/ozad070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 05/26/2023] [Accepted: 06/18/2023] [Indexed: 07/26/2023]
Abstract
Measuring local polar ordering is key to understanding ferroelectricity in thin films, especially for systems with small domains or significant disorder. Scanning nanobeam electron diffraction (NBED) provides an effective local probe of lattice parameters, local fields, polarization directions, and charge densities, which can be analyzed using a relatively low beam dose over large fields of view. However, quantitatively extracting the magnitudes and directions of polarization vectors from NBED remains challenging. Here, we use a cepstral approach, similar to a pair distribution function, to determine local polar displacements that drive ferroelectricity from NBED patterns. Because polar distortions generate asymmetry in the diffraction pattern intensity, we can efficiently recover the underlying displacements from the imaginary part of the cepstrum transform. We investigate the limits of this technique using analytical and simulated data and give experimental examples, achieving the order of 1.1 pm precision and mapping of polar displacements with nanometer resolution.
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Affiliation(s)
- Megan E Holtz
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
- School of Applied and Engineering Physics, Cornell University, 142 Sciences Drive, Ithaca, NY 14853, USA
- Department of Metallurgical and Materials Engineering, Colorado School of Mines, 1301 19th Street, Golden, CO 80401, USA
| | - Elliot Padgett
- School of Applied and Engineering Physics, Cornell University, 142 Sciences Drive, Ithaca, NY 14853, USA
| | - Aaron C Johnston-Peck
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
| | - Igor Levin
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
| | - David A Muller
- School of Applied and Engineering Physics, Cornell University, 142 Sciences Drive, Ithaca, NY 14853, USA
| | - Andrew A Herzing
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
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2
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Johnston-Peck AC, Maier RA. Adlayer formation on C-plane (0001) and R-plane ( 1 1 ‒ 0 2 ) Al 2O 3 surfaces. J Am Ceram Soc 2023; 106:1490-1499. [PMID: 36761689 PMCID: PMC9903351 DOI: 10.1111/jace.18814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 09/17/2022] [Indexed: 06/18/2023]
Abstract
Adlayers on C-plane (0001) and R-plane ( 1 1 ‒ 02 ) terminated surfaces of corundum phase aluminum oxide were synthesized by annealing mixtures of two oxide powders, aluminum oxide with an additive. Using high-angle annular dark field scanning transmission electron microscopy, the adsorbed layers were characterized, and image simulations aided interpretation of the results. The adlayers were pseudomorphic, one atomic layer thick and with a fractional site occupancy. Atomic positions of the adlayer atoms relaxed and changed relative to the bulk structure, where there is evidence that the magnitude of the relaxation is sensitive to the ionic radius of the adsorbate. The pseudomorphic adlayer structure formed for different elements including, but not limited to, the lanthanides (i.e., Ge, Ba and Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm).
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Affiliation(s)
- Aaron C Johnston-Peck
- Material Measurement Laboratory National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899 United States
| | - Russell A Maier
- Material Measurement Laboratory National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899 United States
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3
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Huang W, Johnston-Peck AC, Wolter T, Yang WCD, Xu L, Oh J, Reeves BA, Zhou C, Holtz ME, Herzing AA, Lindenberg AM, Mavrikakis M, Cargnello M. Steam-created grain boundaries for methane C-H activation in palladium catalysts. Science 2021; 373:1518-1523. [PMID: 34554810 DOI: 10.1126/science.abj5291] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Weixin Huang
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Aaron C Johnston-Peck
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Trenton Wolter
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Wei-Chang D Yang
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Lang Xu
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Jinwon Oh
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Benjamin A Reeves
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Chengshuang Zhou
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Megan E Holtz
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Andrew A Herzing
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Aaron M Lindenberg
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA.,Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Manos Mavrikakis
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Matteo Cargnello
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.,SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
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4
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Nikoobakht B, Johnston-Peck AC, Laleyan D, Wang P, Mi Z. Surface-directed ZnGa 2O 4 and β-Ga 2O 3 nanofins coated with a non-polar GaN shell based on the Kirkendall effect. CrystEngComm 2021. [DOI: 10.1039/d1ce00744k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Transformation of laterally grown ZnO nanofins by replacing Zn with Ga via the “Kirkendall Effect”.
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Affiliation(s)
- Babak Nikoobakht
- Materials Measurement Science Division, National Institute of Standards and Technology, Mailstop 8372, Gaithersburg, 20899, MD, USA
| | - Aaron C. Johnston-Peck
- Materials Measurement Science Division, National Institute of Standards and Technology, Mailstop 8372, Gaithersburg, 20899, MD, USA
| | - David Laleyan
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, 1301 Beal Avenue, Ann Arbor, MI 48105, USA
| | - Ping Wang
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, 1301 Beal Avenue, Ann Arbor, MI 48105, USA
| | - Zetian Mi
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, 1301 Beal Avenue, Ann Arbor, MI 48105, USA
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5
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Holm A, Goodman ED, Stenlid JH, Aitbekova A, Zelaya R, Diroll BT, Johnston-Peck AC, Kao KC, Frank CW, Pettersson LGM, Cargnello M. Nanoscale Spatial Distribution of Supported Nanoparticles Controls Activity and Stability in Powder Catalysts for CO Oxidation and Photocatalytic H 2 Evolution. J Am Chem Soc 2020; 142:14481-14494. [PMID: 32786792 PMCID: PMC7924732 DOI: 10.1021/jacs.0c03842] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Supported metal nanoparticles are essential components of high-performing catalysts, and their structures are intensely researched. In comparison, nanoparticle spatial distribution in powder catalysts is conventionally not quantified, and the influence of this collective property on catalyst performance remains poorly investigated. Here, we demonstrate a general colloidal self-assembly method to control uniformity of nanoparticle spatial distribution on common industrial powder supports. We quantify distributions on the nanoscale using image statistics and show that the type of nanospatial distribution determines not only the stability, but also the activity of heterogeneous catalysts. Widely investigated systems (Au-TiO2 for CO oxidation thermocatalysis and Pd-TiO2 for H2 evolution photocatalysis) were used to showcase the universal importance of nanoparticle spatial organization. Spatially and temporally resolved microkinetic modeling revealed that nonuniformly distributed Au nanoparticles suffer from local depletion of surface oxygen, and therefore lower CO oxidation activity, as compared to uniformly distributed nanoparticles. Nanoparticle spatial distribution also determines the stability of Pd-TiO2 photocatalysts, because nonuniformly distributed nanoparticles sinter while uniformly distributed nanoparticles do not. This work introduces new tools to evaluate and understand catalyst collective (ensemble) properties in powder catalysts, which thereby pave the way to more active and stable heterogeneous catalysts.
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Affiliation(s)
- Alexander Holm
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA 94305, USA
- Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Emmett D. Goodman
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA 94305, USA
| | - Joakim Halldin Stenlid
- Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Aisulu Aitbekova
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA 94305, USA
| | - Rosadriana Zelaya
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA 94305, USA
| | - Benjamin T. Diroll
- Center for Nanoscale Materials, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, USA
| | - Aaron C. Johnston-Peck
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Kun-Che Kao
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA 94305, USA
| | - Curtis W. Frank
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Lars G. M. Pettersson
- Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Matteo Cargnello
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA 94305, USA
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6
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Guo W, Johnston-Peck AC, Zhang Y, Hu Y, Huang J, Wei WD. Cooperation of Hot Holes and Surface Adsorbates in Plasmon-Driven Anisotropic Growth of Gold Nanostars. J Am Chem Soc 2020; 142:10921-10925. [PMID: 32484345 DOI: 10.1021/jacs.0c03342] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Light-driven synthesis of plasmonic metal nanostructures has garnered broad scientific interests. Although it has been widely accepted that surface plasmon resonance (SPR)-generated energetic electrons play an essential role in this photochemical process, the exact function of plasmon-generated hot holes in regulating the morphology of nanostructures has not been fully explored. Herein, we discover that those hot holes work with surface adsorbates collectively to control the anisotropic growth of gold (Au) nanostructures. Specifically, it is found that hot holes stabilized by surface adsorbed iodide enable the site-selective oxidative etching of Au0, which leads to nonuniform growths along different lateral directions to form six-pointed Au nanostars. Our studies establish a molecular-level understanding of the mechanism behind the plasmon-driven synthesis of Au nanostars and illustrate the importance of cooperation between charge carriers and surface adsorbates in regulating the morphology evolution of plasmonic nanostructures.
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Affiliation(s)
- Wenxiao Guo
- Department of Chemistry and Center for Catalysis, University of Florida, Gainesville, Florida 32611, United States
| | - Aaron C Johnston-Peck
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | - Yuchao Zhang
- Department of Chemistry and Center for Catalysis, University of Florida, Gainesville, Florida 32611, United States
| | - Yue Hu
- Department of Chemistry and Center for Catalysis, University of Florida, Gainesville, Florida 32611, United States
| | - Jiawei Huang
- Department of Chemistry and Center for Catalysis, University of Florida, Gainesville, Florida 32611, United States
| | - Wei David Wei
- Department of Chemistry and Center for Catalysis, University of Florida, Gainesville, Florida 32611, United States
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7
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Goodman ED, Johnston-Peck AC, Dietze EM, Wrasman CJ, Hoffman AS, Abild-Pedersen F, Bare SR, Plessow PN, Cargnello M. Supported Catalyst Deactivation by Decomposition into Single Atoms Is Suppressed by Increasing Metal Loading. Nat Catal 2019; 2. [PMID: 32118197 DOI: 10.1038/s41929-019-0328-1] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the high-temperature environments needed to perform catalytic processes, supported precious metal catalysts severely lose their activity over time. Even brief exposure to high temperatures can lead to significant losses in activity, which forces manufacturers to use large amounts of noble metals to ensure effective catalyst function for a required lifetime. Generally, loss of catalytic activity is attributed to nanoparticle sintering, or processes by which larger particles grow at the expense of smaller ones. Here, by independently controlling particle size and particle loading using colloidal nanocrystals, we reveal the opposite process as a novel deactivation mechanism: nanoparticles rapidly lose activity by high-temperature nanoparticle decomposition into inactive single atoms. This deactivation route is remarkably fast, leading to severe loss of activity in as little as ten minutes. Importantly, this deactivation pathway is strongly dependent on particle density and concentration of support defect sites. A quantitative statistical model explains how for certain reactions, higher particle densities can lead to more stable catalysts.
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Affiliation(s)
- Emmett D Goodman
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA 94305, USA
| | - Aaron C Johnston-Peck
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, 20899, USA
| | - Elisabeth M Dietze
- Institute of Catalysis Research and Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Cody J Wrasman
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA 94305, USA
| | - Adam S Hoffman
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, CA 94025, USA
| | - Frank Abild-Pedersen
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA 94305, USA.,Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, CA 94025, USA
| | - Simon R Bare
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, CA 94025, USA
| | - Philipp N Plessow
- Institute of Catalysis Research and Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Matteo Cargnello
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA 94305, USA
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8
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Sims CM, Maier RA, Johnston-Peck AC, Gorham JM, Hackley VA, Nelson BC. Approaches for the quantitative analysis of oxidation state in cerium oxide nanomaterials. Nanotechnology 2019; 30:085703. [PMID: 30240366 PMCID: PMC6351072 DOI: 10.1088/1361-6528/aae364] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Cerium oxide nanomaterials (nanoceria, CNMs) are receiving increased attention from the research community due to their unique chemical properties, most prominent of which is their ability to alternate between the Ce3+ and Ce4+ oxidation states. While many analytical techniques and methods have been employed to characterize the amounts of Ce3+ and Ce4+ present (Ce3+/Ce4+ ratio) within nanoceria materials, to-date no studies have used multiple complementary analytical tools (orthogonal analysis) with technique-independent oxidation state controls for quantitative determinations of the Ce3+/Ce4+ ratio. Here, we describe the development of analytical methods measuring the oxidation states of nanoceria analytes using technique-independent Ce3+ (CeAlO3:Ge) and Ce4+ (CeO2) control materials, with a particular focus on x-ray photoelectron spectroscopy (XPS) and electron energy loss spectroscopy (EELS) approaches. The developed methods were demonstrated in characterizing a suite of commercial nanoceria products, where the two techniques (XPS and EELS) were found to be in good agreement with respect to Ce3+/Ce4+ ratio. Potential sources of artifacts and discrepancies in the measurement results were also identified and discussed, alongside suggestions for interpreting oxidation state results using the different analytical techniques. The results should be applicable towards producing more consistent and reproducible oxidation state analyses of nanoceria materials.
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Affiliation(s)
- Christopher M. Sims
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
| | - Russell A. Maier
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
| | - Aaron C. Johnston-Peck
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
| | - Justin M. Gorham
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
| | - Vincent A. Hackley
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
| | - Bryant C. Nelson
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
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9
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Zhang F, Allen AJ, Johnston-Peck AC, Liu J, Pettibone JM. Transformation of engineered nanomaterials through the prism of silver sulfidation. Nanoscale Adv 2019; 1:241-253. [PMID: 31276100 PMCID: PMC6605090 DOI: 10.1039/c8na00103k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 08/02/2018] [Indexed: 05/27/2023]
Abstract
Understanding the structure transformation of engineered nanomaterials (ENMs) is a grand measurement challenge, which impacts many aspects of ENMs applications, such as their efficacy, safety, and environmental consequence. To address the significant knowledge gap regarding the fundamental kinetic rate and extent of ENM transformation in the environment, we present a comprehensive and mechanistic structural investigation of the transformation, aggregation, and dissolution behavior of a polyvinylpyrrolidone-coated silver nanoparticle (AgNP) suspension upon sulfidation in moderately reduced hard water with fulvic acid and dissolved Na2S. This reaction is among the most prevalent and industrially and environmentally relevant ENMs transformation. Using ex situ transmission electron microscopy (TEM) and both in situ and ex situ synchrotron-based small angle X-ray scattering (SAXS) and X-ray diffraction (XRD), we find that sulfidation of faceted AgNPs strongly depends on the crystallographic orientation of the facets, with nanometer-scale passivation layers developed on {111} and {100} facets and continuous nucleation and growth on {110} facets. Nanobeam electron diffraction and atomic resolution imaging show Ag and Ag2S domains both possess a high degree of crystalline order, contradicting amorphous structures as previously reported. In situ SAXS/XRD allowed simultaneous determination of the morphological changes and extent of sulfidation of AgNPs. SAXS/XRD results strongly indicate sulfidation follows first-order reaction kinetics without any aggregation. Aided by their size monodispersity, for the first time, using direct, in situ morphology and atomic-structure probes whose results mutually corroborate, we unequivocally determined the sulfidation rate constant of AgNPs under an environmentally relevant condition (~0.013 min-1 for 68 nm diameter AgNPs). A rigorous analysis of the long-term sulfidation product of the AgNPs under different S/Ag ratios using ex situ SAXS/XRD clearly demonstrates that the silver mass in the original AgNP and transformed Ag/Ag2S NP is preserved. This result has important environmental implications, strongly suggesting that Ag+ ions, a known highly effective antimicrobial agent, are not leached into the solution during sulfidation of AgNPs. The combined nondestructive methodology can be extended to unfold the structure transformation pathway and kinetics in a broad range of ENM systems.
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Affiliation(s)
- Fan Zhang
- Materials Measurement Science Division, National Institute of Standards and TechnologyGaithersburgMD 20899USA
| | - Andrew J. Allen
- Materials Measurement Science Division, National Institute of Standards and TechnologyGaithersburgMD 20899USA
| | - Aaron C. Johnston-Peck
- Materials Measurement Science Division, National Institute of Standards and TechnologyGaithersburgMD 20899USA
| | - Jingyu Liu
- Materials Measurement Science Division, National Institute of Standards and TechnologyGaithersburgMD 20899USA
| | - John M. Pettibone
- Materials Measurement Science Division, National Institute of Standards and TechnologyGaithersburgMD 20899USA
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10
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Liu J, Zhang F, Allen AJ, Johnston-Peck AC, Pettibone JM. Comparing sulfidation kinetics of silver nanoparticles in simulated media using direct and indirect measurement methods. Nanoscale 2018; 10:22270-22279. [PMID: 30465677 PMCID: PMC6624851 DOI: 10.1039/c8nr06668j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Reported reaction kinetics of metal nanoparticles in natural and engineered systems commonly have used proxy measurements to infer chemical transformations, but extension of these methods to complex media has proven difficult. Here, we compare the sulfidation rate of AgNPs using two ion selective electrode (ISE)-based methods, which rely on either (i) direct measurement of free sulfide, or (ii) monitor the free Ag+ available in solution over time in the presence of sulfide species. Most experiments were carried out in moderately hard reconstituted water at pH 7 containing fulvic acid or humic acid, which represented a broad set of known interferences in ISE. Distinct differences in the measured rates were observed between the two proxy-based methods and details of the divergent results are discussed. The two ISE based methods were then compared to direct monitoring of AgNP chemical conversion to Ag2S using synchrotron-based in situ X-ray diffraction (XRD). Using XRD, distinct rates from both ISE-based technique were observed, which demonstrated that ISE measurements alone are inadequate to discriminate both the rate and extent of AgNP sulfidation. XRD rate data elucidated previously unidentified reaction regimes that were associated with AgNP coating (PVP and citrate acid) and NOM components, which provided new mechanistic insight into metallic NP processing. In general, the extent of Ag2S formation was inversely proportional to surface coverage of the initial AgNP. Overall, methods to determine reaction kinetics of nanomaterials in increasingly complex media and heterogeneous size distributions to improve NP-based design and performance will require similar approaches.
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Affiliation(s)
- Jingyu Liu
- National Institute of Standards and Technology, Gaithersburg, Maryland, USA.
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11
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Johnston-Peck AC, Yang WCD, Winterstein JP, Sharma R, Herzing AA. In situ oxidation and reduction of cerium dioxide nanoparticles studied by scanning transmission electron microscopy. Micron 2018; 115:54-63. [PMID: 30212712 DOI: 10.1016/j.micron.2018.08.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 08/23/2018] [Accepted: 08/24/2018] [Indexed: 11/29/2022]
Abstract
Cerium dioxide nanocubes and truncated octahedra were reduced and oxidized in the scanning transmission electron microscope. The reduction process was stimulated by the electron beam and oxidation was supported by background gases in the microscope environment. High-angle annular dark field imaging is sensitive to local lattice distortions that arise as oxygen vacancies are created and cerium cations reduce enabling high spatial resolution characterization of this process with temporal resolution on the order of seconds. Such measurements enable us to differentiate and infer that the observed behavior between the nanocubes and truncated octahedra may be due to the difference in crystallographic termination of surfaces. In situ measurements taken with different partial pressures of oxygen reveal the cerium oxidation state and the dose rate threshold for the onset of beam reduction are influenced by the environment. Increasing oxygen partial pressure reduces the Ce3+ content and decreases susceptibility to electron beam driven reduction.
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Affiliation(s)
- Aaron C Johnston-Peck
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
| | - Wei-Chang D Yang
- Center for Nanoscience and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA; Maryland NanoCenter University of Maryland College Park, MD 20742, USA
| | - Jonathan P Winterstein
- Center for Nanoscience and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Renu Sharma
- Center for Nanoscience and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Andrew A Herzing
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
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12
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Johnston-Peck AC, Takeuchi S, Bharathi KK, Herzing AA, Bendersky LA. Domain Formation in Lithium-Rich Manganese-Nickel-Cobalt-Oxide Epitaxial Thin Films and Implications for Interpretation of Electrochemical Behavior. Thin Solid Films 2018; 647:https://doi.org/10.1016/j.tsf.2017.12.006. [PMID: 33060869 PMCID: PMC7552893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Due to the directional dependence of physical properties, it is advantageous to grow and then study materials in specific orientations. Films of battery materials grown in epitaxy offers the possibility to gain new insight into the role of physical structure on electrochemical behaviors. Here we demonstrate the growth, testing, and characterization of monoclinic-phase (space group C2/m) Li-Mn-Ni-Co-O epitaxial films. The monoclinic phase is a layered structure and as such lithium diffusion is favored along specific crystallographic directions. Films were grown by pulsed laser deposition onto SrRuO3/SrTiO3 substrates with (001) and (111) orientations. Cyclic voltammetry measured the response of these positive electrode materials, while the film structure was characterized using scanning transmission electron microscopy. A combination of imaging and diffraction identifies the presence of orientational variants. Variants disrupt the orientation anisotropy expected of these layered materials when grown in epitaxy, thereby masking differences in electrochemical behavior as a function of substrate orientation. Learning to control the domain structure now presents itself as a challenge to realize the potential of low symmetry battery materials grown in epitaxy on high symmetry substrates.
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13
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Johnston-Peck AC, Takeuchi S, Bharathi KK, Herzing AA, Bendersky LA. Local degradation pathways in lithium-rich manganese-nickel-cobalt-oxide epitaxial thin films. J Mater Sci 2018; 53:https://doi.org/10.1007/s10853-017-1593-5. [PMID: 33060866 PMCID: PMC7552892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The electrochemical performance and microstructure of positive electrodes are intimately linked. As such, developing batteries resistance to capacity and voltage fade requires understanding these underlying structure-properties relationships and their evolution with operation. Epitaxial films of a Li-rich manganese-nickel- cobalt oxide cathode material were deposited on (100) and (111) orientated SrRuO3/SrTiO3 substrates. Cyclic voltammetry and impedance spectroscopy tracked the response of these positive electrode materials, while the microstructure of the pristine and cycled films was characterized using transmission electron microscopy. Energy-dispersive X-ray spectroscopy identifies compositional fluctuations in as-deposited films. Phase transformations and dissolution were observed after electrochemical testing. There is a correlation between both local composition and substrate orientation (i.e., surface faceting) and what degradation pathways are active. Regions with comparatively higher concentrations of Ni and Co were more resistant to dissolution and unfavorable phase transformations than those with relatively more Mn. As such, a global composition metric may not be an accurate predictor of degradation and performance. Rather possessing the synthetic ability to engineer the chemical profile as well as characterizing it, pose a challenge and opportunity.
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Affiliation(s)
- Aaron C Johnston-Peck
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Saya Takeuchi
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - K Kamala Bharathi
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Andrew A Herzing
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Leonid A Bendersky
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
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14
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Abstract
A pristine Li-rich layered electrode material with composition Li1.2Mn0.55Ni0.15Co0.1O2 was characterized by X-ray diffraction, transmission electron microscopy, and scanning transmission electron microscopy to determine whether it is a coherent mixture of monoclinic C2/m Li2MO3 and trigonal [Formula: see text] LiMO2 phases or a solid solution of the monoclinic phase. Contradictory results have been previously reported which can be attributed to the complexity and structural similarity of the monoclinic and trigonal phases. We resolved this uncertainty by combining diffraction and imaging techniques that probe complimentary length scales. Our results demonstrate that the structure is primarily monoclinic, supporting the solid solution model, although near surface structural alterations were also observed.
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Affiliation(s)
- Aaron C Johnston-Peck
- Materials Measurement Laboratory, National Institute of Standards Technology, Gaithersburg, MD 20899 USA
| | - Igor Levin
- Materials Measurement Laboratory, National Institute of Standards Technology, Gaithersburg, MD 20899 USA
| | - Andrew A Herzing
- Materials Measurement Laboratory, National Institute of Standards Technology, Gaithersburg, MD 20899 USA
| | - Leonid A Bendersky
- Materials Measurement Laboratory, National Institute of Standards Technology, Gaithersburg, MD 20899 USA
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15
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Zhai Y, DuChene JS, Wang YC, Qiu J, Johnston-Peck AC, You B, Guo W, DiCiaccio B, Qian K, Zhao EW, Ooi F, Hu D, Su D, Stach EA, Zhu Z, Wei WD. Polyvinylpyrrolidone-induced anisotropic growth of gold nanoprisms in plasmon-driven synthesis. Nat Mater 2016; 15:889-95. [PMID: 27376686 DOI: 10.1038/nmat4683] [Citation(s) in RCA: 144] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 05/31/2016] [Indexed: 05/22/2023]
Abstract
After more than a decade, it is still unknown whether the plasmon-mediated growth of silver nanostructures can be extended to the synthesis of other noble metals, as the molecular mechanisms governing the growth process remain elusive. Herein, we demonstrate the plasmon-driven synthesis of gold nanoprisms and elucidate the details of the photochemical growth mechanism at the single-nanoparticle level. Our investigation reveals that the surfactant polyvinylpyrrolidone preferentially adsorbs along the nanoprism perimeter and serves as a photochemical relay to direct the anisotropic growth of gold nanoprisms. This discovery confers a unique function to polyvinylpyrrolidone that is fundamentally different from its widely accepted role as a crystal-face-blocking ligand. Additionally, we find that nanocrystal twinning exerts a profound influence on the kinetics of this photochemical process by controlling the transport of plasmon-generated hot electrons to polyvinylpyrrolidone. These insights establish a molecular-level description of the underlying mechanisms regulating the plasmon-driven synthesis of gold nanoprisms.
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Affiliation(s)
- Yueming Zhai
- Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, USA
| | - Joseph S DuChene
- Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, USA
| | - Yi-Chung Wang
- Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, USA
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 3335 Q Avenue, Richland, Washington 99354, USA
| | - Jingjing Qiu
- Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, USA
| | - Aaron C Johnston-Peck
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Bo You
- Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, USA
| | - Wenxiao Guo
- Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, USA
| | - Benedetto DiCiaccio
- Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, USA
| | - Kun Qian
- Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, USA
| | - Evan W Zhao
- Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, USA
| | - Frances Ooi
- Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, USA
| | - Dehong Hu
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 3335 Q Avenue, Richland, Washington 99354, USA
| | - Dong Su
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Eric A Stach
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Zihua Zhu
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 3335 Q Avenue, Richland, Washington 99354, USA
| | - Wei David Wei
- Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, USA
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16
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Johnston-Peck AC, DuChene JS, Roberts AD, Wei WD, Herzing AA. Dose-rate-dependent damage of cerium dioxide in the scanning transmission electron microscope. Ultramicroscopy 2016; 170:1-9. [PMID: 27469265 DOI: 10.1016/j.ultramic.2016.07.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 06/17/2016] [Accepted: 07/03/2016] [Indexed: 11/15/2022]
Abstract
Beam damage caused by energetic electrons in the transmission electron microscope is a fundamental constraint limiting the collection of artifact-free information. Through understanding the influence of the electron beam, experimental routines may be adjusted to improve the data collection process. Investigations of CeO2 indicate that there is not a critical dose required for the accumulation of electron beam damage. Instead, measurements using annular dark field scanning transmission electron microscopy and electron energy loss spectroscopy demonstrate that the onset of measurable damage occurs when a critical dose rate is exceeded. The mechanism behind this phenomenon is that oxygen vacancies created by exposure to a 300keV electron beam are actively annihilated as the sample re-oxidizes in the microscope environment. As a result, only when the rate of vacancy creation exceeds the recovery rate will beam damage begin to accumulate. This observation suggests that dose-intensive experiments can be accomplished without disrupting the native structure of the sample when executed using dose rates below the appropriate threshold. Furthermore, the presence of an encapsulating carbonaceous layer inhibits processes that cause beam damage, markedly increasing the dose rate threshold for the accumulation of damage.
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Affiliation(s)
- Aaron C Johnston-Peck
- Materials Measurement Lab, National Institute of Standards Technology, Gaithersburg, MD 20899, USA.
| | - Joseph S DuChene
- Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, FL 32611, USA
| | - Alan D Roberts
- Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, FL 32611, USA
| | - Wei David Wei
- Department of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, FL 32611, USA
| | - Andrew A Herzing
- Materials Measurement Lab, National Institute of Standards Technology, Gaithersburg, MD 20899, USA
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17
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Yao SY, Xu WQ, Johnston-Peck AC, Zhao FZ, Liu ZY, Luo S, Senanayake SD, Martínez-Arias A, Liu WJ, Rodriguez JA. Morphological effects of the nanostructured ceria support on the activity and stability of CuO/CeO2 catalysts for the water-gas shift reaction. Phys Chem Chem Phys 2014; 16:17183-95. [PMID: 25012908 DOI: 10.1039/c4cp02276a] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three CuO/CeO2 catalyst with different morphologies of ceria, namely nanospheres, nanorods and nanocubes, were synthesized and used to catalyze the water-gas shift (WGS) reaction. The reactivity tests showed that the Cu supported on the ceria nanospheres exhibited both the highest activity and superior stability when compared with the nanocube and nanorod ceria catalysts. Operando X-ray diffraction (XRD), X-ray absorption fine structure (XAFS) and diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) methods were used to characterize these catalysts in their working state. High resolution electron microscopy (HRTEM, STEM) was used to look at the local atomic structure and nano-scale morphology. Our results show that the morphology of the ceria support, which can involve different crystal faces and concentrations of defects and imperfections, has a critical impact on the catalytic properties and influences: (1) the dispersion of CuO in the as-synthesized catalyst; (2) the particle size of metallic Cu upon reduction during the WGS reaction, (3) the stability of the metallic Cu upon variations of temperature, and (4) the dissociation of water on the ceria support. The nanosphere ceria catalyst showed an excellent water dissociation capability, the best dispersion of Cu and a strong Cu-Ce interaction, therefore delivering the best performance among the three WGS catalysts. The metallic Cu, which is the active species during the WGS reaction, was more stabilized on the nanospheres than on the nanorods and nanocubes and thus led to a better stability of the nanosphere catalyst than the other two architectures. Each catalyst exhibited a distinctive line-shape in the 800-1600 cm(-1) region of the DRIFTS spectra, pointing to the existence of different types of carbonate or carboxylate species as surface intermediates for the WGS.
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Affiliation(s)
- S Y Yao
- Center for Computational Science & Engineering and Green Chemistry Center, Peking University, Beijing 100871, China.
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18
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Qian K, Sweeny BC, Johnston-Peck AC, Niu W, Graham JO, DuChene JS, Qiu J, Wang YC, Engelhard MH, Su D, Stach EA, Wei WD. Surface Plasmon-Driven Water Reduction: Gold Nanoparticle Size Matters. J Am Chem Soc 2014; 136:9842-5. [DOI: 10.1021/ja504097v] [Citation(s) in RCA: 262] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Kun Qian
- Department
of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, United States
| | - Brendan C. Sweeny
- Department
of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, United States
| | - Aaron C. Johnston-Peck
- Center
for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Wenxin Niu
- Department
of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, United States
| | - Jeremy O. Graham
- Department
of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, United States
| | - Joseph S. DuChene
- Department
of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, United States
| | - Jingjing Qiu
- Department
of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, United States
| | - Yi-Chung Wang
- Department
of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, United States
| | - Mark H. Engelhard
- Environmental
Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Dong Su
- Center
for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Eric A. Stach
- Center
for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Wei David Wei
- Department
of Chemistry and Center for Nanostructured Electronic Materials, University of Florida, Gainesville, Florida 32611, United States
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19
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DuChene JS, Sweeny BC, Johnston-Peck AC, Su D, Stach EA, Wei WD. Prolonged Hot Electron Dynamics in Plasmonic-Metal/Semiconductor Heterostructures with Implications for Solar Photocatalysis. Angew Chem Int Ed Engl 2014; 53:7887-91. [DOI: 10.1002/anie.201404259] [Citation(s) in RCA: 301] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Indexed: 11/08/2022]
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20
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DuChene JS, Sweeny BC, Johnston-Peck AC, Su D, Stach EA, Wei WD. Prolonged Hot Electron Dynamics in Plasmonic-Metal/Semiconductor Heterostructures with Implications for Solar Photocatalysis. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201404259] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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21
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Yao S, Mudiyanselage K, Xu W, Johnston-Peck AC, Hanson JC, Wu T, Stacchiola D, Rodriguez JA, Zhao H, Beyer KA, Chapman KW, Chupas PJ, Martínez-Arias A, Si R, Bolin TB, Liu W, Senanayake SD. Unraveling the Dynamic Nature of a CuO/CeO2 Catalyst for CO Oxidation in Operando: A Combined Study of XANES (Fluorescence) and DRIFTS. ACS Catal 2014. [DOI: 10.1021/cs500148e] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Siyu Yao
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
- Center for Computational Science & Engineering, and PKU Green Chemistry Center, Peking University, Beijing 100871, People’s Republic of China
| | - Kumudu Mudiyanselage
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Wenqian Xu
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Aaron C. Johnston-Peck
- Center
for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Jonathan C. Hanson
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Tianpin Wu
- X-ray
Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Dario Stacchiola
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - José A. Rodriguez
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Haiyan Zhao
- X-ray
Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Kevin A. Beyer
- X-ray
Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Karena W. Chapman
- X-ray
Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Peter J. Chupas
- X-ray
Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Arturo Martínez-Arias
- Instituto de Catálisis y Petroleoquímica, Consejo Superior de Investigaciones Científicas (ICP-CSIC), Madrid E-28049, Spain
| | - Rui Si
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Trudy B. Bolin
- X-ray
Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Wenjian Liu
- Center for Computational Science & Engineering, and PKU Green Chemistry Center, Peking University, Beijing 100871, People’s Republic of China
| | - Sanjaya D. Senanayake
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
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22
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Xu W, Liu Z, Johnston-Peck AC, Senanayake SD, Zhou G, Stacchiola D, Stach EA, Rodriguez JA. Steam Reforming of Ethanol on Ni/CeO2: Reaction Pathway and Interaction between Ni and the CeO2 Support. ACS Catal 2013. [DOI: 10.1021/cs4000969] [Citation(s) in RCA: 180] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wenqian Xu
- Chemistry Department and ‡Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973,
United States
| | - Zongyuan Liu
- Chemistry Department and ‡Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973,
United States
| | - Aaron C. Johnston-Peck
- Chemistry Department and ‡Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973,
United States
| | - Sanjaya D. Senanayake
- Chemistry Department and ‡Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973,
United States
| | - Gong Zhou
- Chemistry Department and ‡Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973,
United States
| | - Dario Stacchiola
- Chemistry Department and ‡Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973,
United States
| | - Eric A. Stach
- Chemistry Department and ‡Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973,
United States
| | - José A. Rodriguez
- Chemistry Department and ‡Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973,
United States
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23
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Medford JA, Johnston-Peck AC, Tracy JB. Nanostructural transformations during the reduction of hollow and porous nickel oxide nanoparticles. Nanoscale 2013; 5:155-159. [PMID: 23168915 DOI: 10.1039/c2nr33005a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Size-dependent nanostructural transformations occurring during the H(2)-mediated reduction of hollow and porous NiO nanoparticles were investigated for controlled nanoparticle sizes of ~10 to 100 nm. Transmission electron microscopy reveals that the location and number of reduction sites strongly depend on the nanoparticle size and structure.
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Affiliation(s)
- John A Medford
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA
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24
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Krommenhoek PJ, Wang J, Hentz N, Johnston-Peck AC, Kozek KA, Kalyuzhny G, Tracy JB. Bulky adamantanethiolate and cyclohexanethiolate ligands favor smaller gold nanoparticles with altered discrete sizes. ACS Nano 2012; 6:4903-11. [PMID: 22702463 DOI: 10.1021/nn3003778] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Use of bulky ligands (BLs) in the synthesis of metal nanoparticles (NPs) gives smaller core sizes, sharpens the size distribution, and alters the discrete sizes. For BLs, the highly curved surface of small NPs may facilitate growth, but as the size increases and the surface flattens, NP growth may terminate when the ligand monolayer blocks BLs from transporting metal atoms to the NP core. Batches of thiolate-stabilized Au NPs were synthesized using equimolar amounts of 1-adamantanethiol (AdSH), cyclohexanethiol (CySH), or n-hexanethiol (C6SH). The bulky CyS- and AdS-stabilized NPs have smaller, more monodisperse sizes than the C6S-stabilized NPs. As the bulkiness increases, the near-infrared luminescence intensity increases, which is characteristic of small Au NPs. Four new discrete sizes were measured by MALDI-TOF mass spectrometry, Au(30)(SAd)(18), Au(39)(SAd)(23), Au(65)(SCy)(30), and Au(67)(SCy)(30). No Au(25)(SAd)(18) was observed, which suggests that this structure would be too sterically crowded. Use of BLs may also lead to the discovery of new discrete sizes in other systems.
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Affiliation(s)
- Peter J Krommenhoek
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
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25
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Jie Y, Niskala JR, Johnston-Peck AC, Krommenhoek PJ, Tracy JB, Fan H, You W. Laterally patterned magnetic nanoparticles. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c1jm14612b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Johnston-Peck AC, Scarel G, Wang J, Parsons GN, Tracy JB. Sinter-free phase conversion and scanning transmission electron microscopy of FePt nanoparticle monolayers. Nanoscale 2011; 3:4142-4149. [PMID: 21869998 DOI: 10.1039/c1nr10567a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Thermally robust monolayers of 4-6 nm diameter FePt nanoparticles (NPs) were fabricated by combining chemical synthesis and atomic layer deposition. Spin-cast monolayers of FePt NPs were coated with thin, 11 nm-thick layers of amorphous Al(2)O(3), followed by annealing to convert the FePt NPs from an alloy (A1) into intermetallic FePt (L1(0)) and FePt(3) (L1(2)) phases. The Al(2)O(3) layer serves as a barrier that prevents sintering between NPs during annealing at temperatures up to 730 °C. Electron and X-ray diffraction in conjunction with high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) show that as-synthesized A1 FePt NPs convert into L1(0) and L1(2) phase NPs through annealing. HAADF-STEM measurements of individual NPs reveal imperfect ordering and show that the NP composition determines which intermetallic phase is obtained. Mixed-phase NPs with L1(0) cores and FePt(3) L1(2) shells were also observed, as well as a smaller number of unconverted A1 NPs. These results highlight the need for improved control over the compositional uniformity of FePt NPs for their use in bit-patterned magnetic recording.
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Affiliation(s)
- Aaron C Johnston-Peck
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA
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27
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Abstract
Ligand-stabilized magnetic nanoparticles (NPs) with diameters of 4-7 nm were spin-cast into monolayers on electron-transparent silicon nitride (SiN) substrates. SiN membranes facilitate detailed high-resolution characterization of the spin-cast monolayers by transmission electron microscopy (TEM) and approximate spin-casting onto wafers. Suspending the NPs in hexanes and pretreating the substrate with ultraviolet light and ozone (UVO) gives the best results. Computer-aided analysis of the arrays elucidates their grain structures, including identification of the grain boundaries and defects and measurements of the grain orientations and translational correlation lengths. Narrow NP size distributions result in close-packed arrays with minimal defects and large grains containing thousands of NPs. Edge dislocations, interstitials, vacancies, and overlapping NPs were observed. Deviations from close packing occur as the normalized standard deviation of the sample's size distribution increases above approximately 11%. Polydisperse size distributions and deviations from spherical NP shapes frustrate assembly and prevent ordered packing.
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Affiliation(s)
- Aaron C Johnston-Peck
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
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28
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Chhetri RK, Kozek KA, Johnston-Peck AC, Tracy JB, Oldenburg AL. Imaging three-dimensional rotational diffusion of plasmon resonant gold nanorods using polarization-sensitive optical coherence tomography. Phys Rev E Stat Nonlin Soft Matter Phys 2011; 83:040903. [PMID: 21599108 PMCID: PMC3116207 DOI: 10.1103/physreve.83.040903] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Indexed: 05/03/2023]
Abstract
We demonstrate depth-resolved viscosity measurements within a single object using polarized optical scattering from ensembles of freely tumbling plasmon resonant gold nanorods (GNRs) monitored with polarization-sensitive optical coherence tomography. The rotational diffusion coefficient of the GNRs is shown to correlate with viscosity in molecular fluids according to the Stokes-Einstein relation. The plasmon resonant and highly anisotropic properties of GNRs are favorable for microrheological studies of nanoscale properties.
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Affiliation(s)
- Raghav K. Chhetri
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Krystian A. Kozek
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Aaron C. Johnston-Peck
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Joseph B. Tracy
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Amy L. Oldenburg
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Author to whom correspondence should be addressed:
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29
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Sarac MF, Wilson RM, Johnston-Peck AC, Wang J, Pearce R, Klein KL, Melechko AV, Tracy JB. Effects of ligand monolayers on catalytic nickel nanoparticles for synthesizing vertically aligned carbon nanofibers. ACS Appl Mater Interfaces 2011; 3:936-940. [PMID: 21410229 DOI: 10.1021/am101290v] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Vertically aligned carbon nanofibers (VACNFs) were synthesized using ligand-stabilized Ni nanoparticle (NP) catalysts and plasma-enhanced chemical vapor deposition. Using chemically synthesized Ni NPs enables facile preparation of VACNF arrays with monodisperse diameters below the size limit of thin film lithography. During pregrowth heating, the ligands catalytically convert into graphitic shells that prevent the catalyst NPs from agglomerating and coalescing, resulting in a monodisperse VACNF size distribution. In comparison, significant agglomeration occurs when the ligands are removed before VACNF growth, giving a broad distribution of VACNF sizes. The ligand shells are also promising for patterning the NPs and synthesizing complex VACNF arrays.
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30
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Shore MS, Wang J, Johnston-Peck AC, Oldenburg AL, Tracy JB. Synthesis of Au(Core)/Ag(Shell) nanoparticles and their conversion to AuAg alloy nanoparticles. Small 2011; 7:230-234. [PMID: 21213387 DOI: 10.1002/smll.201001138] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Revised: 10/25/2010] [Indexed: 05/27/2023]
Affiliation(s)
- Matthew S Shore
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA
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Railsback JG, Johnston-Peck AC, Wang J, Tracy JB. Size-dependent nanoscale kirkendall effect during the oxidation of nickel nanoparticles. ACS Nano 2010; 4:1913-20. [PMID: 20361781 DOI: 10.1021/nn901736y] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The transformation of Ni nanoparticles (NPs) of different sizes (average diameters of 9, 26, and 96 nm) during oxidation to hollow (single void) or porous (multiple voids) NiO through the nanoscale Kirkendall effect was observed by transmission electron microscopy. Samples treated for 1-4 h at 200-500 degrees C show that the structures of the completely oxidized NPs do not depend on the temperature, but oxidation proceeds more quickly at elevated temperatures. For the Ni/NiO system, after formation of an initial NiO shell (of thickness approximately 3 nm), single or multiple voids nucleate on the inner surface of the NiO shell, and the voids grow until conversion to NiO is complete. Differences in the void formation and growth processes cause size-dependent nanostructural evolution: For 9 and 26 nm NPs, a single void forms beneath the NiO shell, and the void grows by moving across the NP while conversion to NiO occurs opposite the site where the void initially formed. Because of the differences in the Ni/NiO volume ratios for the 9 and 26 nm NPs when the void first forms, they have distinct nanostructures: The 9 nm NPs form NiO shells that are nearly radially symmetric, while there is a pronounced asymmetry in the NiO shells for 26 nm NPs. By choosing an intermediate oxidation temperature and varying the reaction time, partially oxidized Ni(core)/NiO(shell) NPs can be synthesized with good control. For 96 nm NPs, multiple voids form and grow, which results in porous NiO NPs.
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Affiliation(s)
- Justin G Railsback
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
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Johnston-Peck AC, Wang J, Tracy JB. Synthesis and structural and magnetic characterization of Ni(core)/NiO(shell) nanoparticles. ACS Nano 2009; 3:1077-1084. [PMID: 19361203 DOI: 10.1021/nn900019x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A size series of ligand-stabilized Ni nanoparticles (NPs) with diameters between 8-24 nm was prepared by solution chemistry, followed by solution-phase oxidation with atmospheric oxygen at 200 degrees C to form Ni(core)/NiO(shell) NPs with shell thicknesses of 2-3 nm. In comparison with the oxidation of Fe and Co NPs, Ni NPs require higher temperatures for significant conversion to NiO. Transmission electron microscopy and electron diffraction show polycrystalline cores with predominantly amorphous shells. SQUID magnetometry measurements were performed to assess the effects of coupling between the ferromagnetic Ni cores and antiferromagnetic NiO shells. After intentional oxidation, the Ni(core)/NiO(shell) NPs have decreased superparamagnetic blocking temperatures (T(B)) and no exchange shift (H(EB)), but a small enhancement in the coercivity (H(C)) signifies weak exchange bias. These effects originate from the amorphous structure of the NiO shells and their thin layer thickness that renders the NiO moments incapable of pinning the core moment in moderate applied fields. The magnetocrystalline anisotropy constants before and after oxidation approach the value for bulk Ni and depend on the Ni core size and NiO shell thickness.
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Affiliation(s)
- Aaron C Johnston-Peck
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
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