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Kang S, Kim JK, Kim H, Son YH, Chang J, Kim J, Kim DW, Lee JM, Kwon HJ. Local Structures of Ex-Solved Nanoparticles Identified by Machine-Learned Potentials. NANO LETTERS 2024; 24:4224-4232. [PMID: 38557115 DOI: 10.1021/acs.nanolett.4c00388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
In this study, we identify the local structures of ex-solved nanoparticles using machine-learned potentials (MLPs). We develop a method for training machine-learned potentials by sampling local structures of heterointerface configurations as a training set with its efficacy tested on the Ni/MgO system, illustrating that the error in interface energy is only 0.004 eV/Å2. Using the developed scheme, we train an MLP for the Ni/La0.5Ca0.5TiO3 ex-solution system and identify the local structures for both exo- and endo-type particles. The established model aligns well with the experimental observations, accurately predicting a nucleation size of 0.45 nm. Lastly, the density functional theory calculations on the established atomistic model verify that the kinetic barrier for the dry reforming of methane are substantially reduced by 0.49 eV on the ex-solved catalysts compared to that on the impregnated catalysts. Our findings offer insights into the local structures, growth mechanisms, and underlying origin of the catalytic properties of ex-solved nanoparticles.
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Affiliation(s)
- Sungwoo Kang
- Air Science Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Company, Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16678, Republic of Korea
| | - Jun Kyu Kim
- Air Science Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Company, Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16678, Republic of Korea
| | - Hyunah Kim
- Air Science Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Company, Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16678, Republic of Korea
| | - You-Hwan Son
- Air Science Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Company, Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16678, Republic of Korea
| | - Jaehee Chang
- Air Science Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Company, Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16678, Republic of Korea
| | - Jinwoo Kim
- Air Science Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Company, Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16678, Republic of Korea
| | - Dong-Wook Kim
- Air Science Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Company, Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16678, Republic of Korea
| | - Jong-Min Lee
- Air Science Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Company, Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16678, Republic of Korea
| | - Hyuk Jae Kwon
- Air Science Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Company, Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16678, Republic of Korea
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Kang X, Reinertsen VM, Both KG, Galeckas A, Aarholt T, Prytz Ø, Norby T, Neagu D, Chatzitakis A. Galvanic Restructuring of Exsolved Nanoparticles for Plasmonic and Electrocatalytic Energy Conversion. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2201106. [PMID: 35695331 DOI: 10.1002/smll.202201106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Revised: 05/07/2022] [Indexed: 06/15/2023]
Abstract
There is a growing need to control and tune nanoparticles (NPs) to increase their stability and effectiveness, especially for photo- and electrochemical energy conversion applications. Exsolved particles are well anchored and can be re-shaped without changing their initial location and structural arrangement. However, this usually involves lengthy treatments and use of toxic gases. Here, the galvanic replacement/deposition method is used, which is simpler, safer, and leads to a wealth of new hybrid nanostructures with a higher degree of tailorability. The produced NiAu bimetallic nanostructures supported on SrTiO3 display exceptional activity in plasmon-assisted photoelectrochemical (PEC) water oxidation reactions. In situ scanning transmission electron microscopy is used to visualize the structural evolution of the plasmonic bimetallic structures, while theoretical simulations provide mechanistic insight and correlate the surface plasmon resonance effects with structural features and enhanced PEC performance. The versatility of this concept in shifting catalytic modes to the hydrogen evolution reaction is demonstrated by preparing hybrid NiPt bimetallic NPs of low Pt loadings on highly reduced SrTiO3 supports. This powerful methodology enables the design of supported bimetallic nanomaterials with tunable morphology and catalytic functionalities through minimal engineering.
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Affiliation(s)
- Xiaolan Kang
- Centre for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, Gaustadalléen 21, Oslo, NO-0349, Norway
| | - Vilde Mari Reinertsen
- Centre for Materials Science and Nanotechnology, Department of Physics, University of Oslo, P. O. Box 1048 Blindern, Oslo, NO-0316, Norway
| | - Kevin Gregor Both
- Centre for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, Gaustadalléen 21, Oslo, NO-0349, Norway
| | - Augustinas Galeckas
- Centre for Materials Science and Nanotechnology, Department of Physics, University of Oslo, P. O. Box 1048 Blindern, Oslo, NO-0316, Norway
| | - Thomas Aarholt
- Centre for Materials Science and Nanotechnology, Department of Physics, University of Oslo, P. O. Box 1048 Blindern, Oslo, NO-0316, Norway
| | - Øystein Prytz
- Centre for Materials Science and Nanotechnology, Department of Physics, University of Oslo, P. O. Box 1048 Blindern, Oslo, NO-0316, Norway
| | - Truls Norby
- Centre for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, Gaustadalléen 21, Oslo, NO-0349, Norway
| | - Dragos Neagu
- Department of Chemical and Process Engineering, University of Strathclyde, 75 Montrose St, Glasgow, G1 1XJ, UK
| | - Athanasios Chatzitakis
- Centre for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, Gaustadalléen 21, Oslo, NO-0349, Norway
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Nakano N, Torimoto M, Sampei H, Yamashita R, Yamano R, Saegusa K, Motomura A, Nagakawa K, Tsuneki H, Ogo S, Sekine Y. Elucidation of the reaction mechanism on dry reforming of methane in an electric field by in situ DRIFTs. RSC Adv 2022; 12:9036-9043. [PMID: 35424901 PMCID: PMC8985195 DOI: 10.1039/d2ra00402j] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 03/14/2022] [Indexed: 01/17/2023] Open
Abstract
With increasing expectations for carbon neutrality, dry reforming is anticipated for direct conversion of methane and carbon dioxide: the main components of biogas. We have found that dry reforming of methane in an electric field using a Pt/CeO2 catalyst proceeds with sufficient rapidity even at a low temperature of about 473 K. The effect of the electric field (EF) on dry reforming was investigated using kinetic analysis, in situ DRIFTs, XPS, and DFT calculation. In situ DRIFTs and XPS measurements indicated that the amount of carbonate, which is an adsorbed species of CO2, increased with the application of EF. XPS measurements also confirmed the reduction of CeO2 by the reaction of surface oxygen and CH4. The reaction between CH4 molecules and surface oxygen was promoted at the interface between Pt and CeO2. In the dry reforming of methane in an electric field, the reaction between CH4 molecules and surface oxygen was promoted at the interface between Pt and CeO2.![]()
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Affiliation(s)
- Naoya Nakano
- Department of Applied Chemistry, Waseda University 3-4-1, Okubo, Shinjuku Tokyo 169-8555 Japan
| | - Maki Torimoto
- Department of Applied Chemistry, Waseda University 3-4-1, Okubo, Shinjuku Tokyo 169-8555 Japan
| | - Hiroshi Sampei
- Department of Applied Chemistry, Waseda University 3-4-1, Okubo, Shinjuku Tokyo 169-8555 Japan
| | - Reiji Yamashita
- Department of Applied Chemistry, Waseda University 3-4-1, Okubo, Shinjuku Tokyo 169-8555 Japan
| | - Ryota Yamano
- Department of Applied Chemistry, Waseda University 3-4-1, Okubo, Shinjuku Tokyo 169-8555 Japan
| | - Koki Saegusa
- Department of Applied Chemistry, Waseda University 3-4-1, Okubo, Shinjuku Tokyo 169-8555 Japan
| | - Ayaka Motomura
- Department of Applied Chemistry, Waseda University 3-4-1, Okubo, Shinjuku Tokyo 169-8555 Japan
| | - Kaho Nagakawa
- Department of Applied Chemistry, Waseda University 3-4-1, Okubo, Shinjuku Tokyo 169-8555 Japan
| | - Hideaki Tsuneki
- Department of Applied Chemistry, Waseda University 3-4-1, Okubo, Shinjuku Tokyo 169-8555 Japan
| | - Shuhei Ogo
- Department of Marine Resources Science, Faculty of Agriculture and Marine Science, Kochi University Nankoku 783-8502 Japan.,Center for Advanced Marine Core Research, Kochi University Nankoku 783-8502 Japan
| | - Yasushi Sekine
- Department of Applied Chemistry, Waseda University 3-4-1, Okubo, Shinjuku Tokyo 169-8555 Japan
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Syed K, Wang J, Yildiz B, Bowman WJ. Bulk and surface exsolution produces a variety of Fe-rich and Fe-depleted ellipsoidal nanostructures in La 0.6Sr 0.4FeO 3 thin films. NANOSCALE 2022; 14:663-674. [PMID: 34874392 DOI: 10.1039/d1nr06121f] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The past several years have seen a resurgence in the popularity of metal exsolution as an approach to synthesize advanced materials proposed for novel catalytic, magnetic, optical, and electrochemical properties. Whereas most studies to-date have focused on surface exsolution (motivated by catalysis), we instead report on the diversity of nanostructures formed in La0.6Sr0.4FeO3 thin films during sub-surface or so-called 'bulk' exsolution, in addition to surface exsolution. Bulk exsolution is a promising approach to tuning the functionality of materials, yet there is little understanding of the nanostructures exsolved within the bulk and how they compare to those exsolved at gas-solid interfaces. This work combines atomic- and nano-scale imaging and spectroscopy techniques applied using a state-of-the-art aberration-corrected scanning transmission electron microscope (STEM). In doing so, we present a detailed atomic-resolution study of a range of Fe-rich and Fe-depleted nanostructures possible via exsolution, along with qualitative and quantitative chemical analysis of the exsolved nanostructures and oxide phases formed throughout the film. Local structural changes in the perovskite matrix, coinciding with nanostructure exsolution, are also characterized with atomic-resolution STEM imaging. Fe exsolution is shown to create local A-site rich domains of Ruddlesden-Popper phase, and some stages of this phase formation have been demonstrated in this work. In particular, phase boundaries are found to be the primary nucleation sites for bulk and surface exsolution, and the exsolved particles observed here tend to be ellipsoidal with shape factor of 1.4. We report a range of nanostructure types (core-shell, bulk core-shell, adjacent, and independent particles), revealing several possible avenues of future exploration aimed to understand the formation mechanism of each exsolution type and to develop their functionality. This work is thus relevant to materials scientists and engineers motivated to understand and utilize exsolution to synthesize materials with predictable nanostructures.
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Affiliation(s)
- Komal Syed
- Department of Materials Science & Engineering, University of California, Irvine, CA, USA.
| | - Jiayue Wang
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Bilge Yildiz
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - William J Bowman
- Department of Materials Science & Engineering, University of California, Irvine, CA, USA.
- Irvine Materials Research Institute, University of California, Irvine, CA, USA
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Riegraf M, Amaya‐Dueñas DM, Sata N, Friedrich KA, Costa R. Performance and Limitations of Nickel-Doped Chromite Anodes in Electrolyte-Supported Solid Oxide Fuel Cells. CHEMSUSCHEM 2021; 14:2401-2413. [PMID: 33844883 PMCID: PMC8252760 DOI: 10.1002/cssc.202100330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/12/2021] [Indexed: 06/12/2023]
Abstract
Ni-doped chromite anodes were integrated into electrolyte-supported cells (ESC) with 5×5 cm2 size and investigated in fuel cell mode with H2 /H2 O fuel gas. Both a stoichiometric and a nominally A-site deficient chromite anode material showed promising performance at 860 °C approaching the ones of state-of-the-art Ni/Gd-doped ceria (CGO) anodes. While the difference in polarization resistance was small, an increased ohmic resistance of the perovskite anodes was observed, which is related to their limited electronic conductivity. Increasing the chromite electrode thickness was shown to enhance performance and stability considerably. Degradation increased with current density, suggesting its dependency on the electrode potential, and could be reversed by redox cycling. Sulfur poisoning with 20 ppm hydrogen sulfide led to rapid voltage drops for the chromite anodes. It is discussed that Ni nanoparticle exsolution facilitates hydrogen dissociation to the extent that it is not rate-limiting at the investigated temperature unless an insufficiently thick electrode thickness is employed or sulfur impurities are present in the feed gas.
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Affiliation(s)
- Matthias Riegraf
- Institute of Engineering Thermodynamics German Aerospace Center (DLR)Pfaffenwaldring 38–4070569StuttgartGermany
| | - Diana M. Amaya‐Dueñas
- Institute of Engineering Thermodynamics German Aerospace Center (DLR)Pfaffenwaldring 38–4070569StuttgartGermany
| | - Noriko Sata
- Institute of Engineering Thermodynamics German Aerospace Center (DLR)Pfaffenwaldring 38–4070569StuttgartGermany
| | - K. Andreas Friedrich
- Institute of Engineering Thermodynamics German Aerospace Center (DLR)Pfaffenwaldring 38–4070569StuttgartGermany
- Institute for Building EnergeticsThermotechnology and Energy StorageUniversity of StuttgartPfaffenwaldring 3170569StuttgartGermany
| | - Rémi Costa
- Institute of Engineering Thermodynamics German Aerospace Center (DLR)Pfaffenwaldring 38–4070569StuttgartGermany
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