1
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Rana R, Vila FD, Kulkarni AR, Bare SR. Bridging the Gap between the X-ray Absorption Spectroscopy and the Computational Catalysis Communities in Heterogeneous Catalysis: A Perspective on the Current and Future Research Directions. ACS Catal 2022. [DOI: 10.1021/acscatal.2c03863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rachita Rana
- Department of Chemical Engineering, University of California, Davis, California95616, United States
| | - Fernando D. Vila
- Department of Physics, University of Washington, Seattle, Washington98195, United States
| | - Ambarish R. Kulkarni
- Department of Chemical Engineering, University of California, Davis, California95616, United States
| | - Simon R. Bare
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California94025, United States
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2
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Morais A, Rijo P, Batanero B, Nicolai M. Low Platinum-Content Electrocatalysts for Highly Sensitive Detection of Endogenously Released H2O2. BIOSENSORS 2022; 12:bios12090672. [PMID: 36140056 PMCID: PMC9496631 DOI: 10.3390/bios12090672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/05/2022] [Accepted: 08/12/2022] [Indexed: 11/16/2022]
Abstract
The commercial viability of electrochemical sensors requires high catalytic efficiency electrode materials. A sluggish reaction of the sensor’s primary target species will require a high overpotential and, consequently, an excessive load of catalyst material to be used. Therefore, it is essential to understand nanocatalysts’ fundamental structures and typical catalytic properties to choose the most efficient material according to the biosensor target species. Catalytic activities of Pt-based catalysts have been significantly improved over the decades. Thus, electrodes using platinum nanocatalysts have demonstrated high power densities, with Pt loading considerably reduced on the electrodes. The high surface-to-volume ratio, higher electron transfer rate, and the simple functionalisation process are the main reasons that transition metal NPs have gained much attention in constructing high-sensitivity sensors. This study has designed to describe and highlight the performances of the different Pt-based bimetallic nanoparticles and alloys as an enzyme-free catalytic material for the sensitive electrochemical detection of H2O2. The current analysis may provide a promising platform for the prospective construction of Pt-based electrodes and their affinity matrix.
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Affiliation(s)
- Ana Morais
- CBIOS—Universidade Lusófona´s Research Centre for Biosciences & Health Technologies, Campo Grande 376, 1749-024 Lisbon, Portugal
- Department of Organic Chemistry & Inorganic Chemistry, University of Alcala, 28805 Alcala de Henares, Spain
| | - Patrícia Rijo
- CBIOS—Universidade Lusófona´s Research Centre for Biosciences & Health Technologies, Campo Grande 376, 1749-024 Lisbon, Portugal
- iMed.Ulisboa—Research Institute for Medicines and Pharmaceutical Sciences, Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 1649-003 Lisbon, Portugal
| | - Belen Batanero
- Department of Organic Chemistry & Inorganic Chemistry, University of Alcala, 28805 Alcala de Henares, Spain
| | - Marisa Nicolai
- CBIOS—Universidade Lusófona´s Research Centre for Biosciences & Health Technologies, Campo Grande 376, 1749-024 Lisbon, Portugal
- Correspondence:
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3
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Li J, Li Y, Routh PK, Makagon E, Lubomirsky I, Frenkel AI. Comparative analysis of XANES and EXAFS for local structural characterization of disordered metal oxides. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:1511-1517. [PMID: 34475298 DOI: 10.1107/s1600577521007025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/07/2021] [Indexed: 06/13/2023]
Abstract
In functional materials, the local environment around active species that may contain just a few nearest-neighboring atomic shells often changes in response to external conditions. Strong disorder in the local environment poses a challenge to commonly used extended X-ray absorption fine structure (EXAFS) analysis. Furthermore, the dilute concentrations of absorbing atoms, small sample size and the constraints of the experimental setup often limit the utility of EXAFS for structural analysis. X-ray absorption near-edge structure (XANES) has been established as a good alternative method to provide local electronic and geometric information of materials. The pre-edge region in the XANES spectra of metal compounds is a useful but relatively under-utilized resource of information of the chemical composition and structural disorder in nano-materials. This study explores two examples of materials in which the transition metal environment is either relatively symmetric or strongly asymmetric. In the former case, EXAFS results agree with those obtained from the pre-edge XANES analysis, whereas in the latter case they are in a seeming contradiction. The two observations are reconciled by revisiting the limitations of EXAFS in the case of a strong, asymmetric bond length disorder, expected for mixed-valence oxides, and emphasize the utility of the pre-edge XANES analysis for detecting local heterogeneities in structural and compositional motifs.
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Affiliation(s)
- Junying Li
- Materials Science and Chemical Engineering, Stony Brook University, 100 Nicolls Road, Stony Brook, NY 11794, USA
| | - Yuanyuan Li
- Materials Science and Chemical Engineering, Stony Brook University, 100 Nicolls Road, Stony Brook, NY 11794, USA
| | - Prahlad K Routh
- Materials Science and Chemical Engineering, Stony Brook University, 100 Nicolls Road, Stony Brook, NY 11794, USA
| | - Evgeniy Makagon
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Igor Lubomirsky
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Anatoly I Frenkel
- Materials Science and Chemical Engineering, Stony Brook University, 100 Nicolls Road, Stony Brook, NY 11794, USA
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4
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Timoshenko J, Roldan Cuenya B. In Situ/ Operando Electrocatalyst Characterization by X-ray Absorption Spectroscopy. Chem Rev 2021; 121:882-961. [PMID: 32986414 PMCID: PMC7844833 DOI: 10.1021/acs.chemrev.0c00396] [Citation(s) in RCA: 184] [Impact Index Per Article: 61.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Indexed: 12/18/2022]
Abstract
During the last decades, X-ray absorption spectroscopy (XAS) has become an indispensable method for probing the structure and composition of heterogeneous catalysts, revealing the nature of the active sites and establishing links between structural motifs in a catalyst, local electronic structure, and catalytic properties. Here we discuss the fundamental principles of the XAS method and describe the progress in the instrumentation and data analysis approaches undertaken for deciphering X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectra. Recent usages of XAS in the field of heterogeneous catalysis, with emphasis on examples concerning electrocatalysis, will be presented. The latter is a rapidly developing field with immense industrial applications but also unique challenges in terms of the experimental characterization restrictions and advanced modeling approaches required. This review will highlight the new insight that can be gained with XAS on complex real-world electrocatalysts including their working mechanisms and the dynamic processes taking place in the course of a chemical reaction. More specifically, we will discuss applications of in situ and operando XAS to probe the catalyst's interactions with the environment (support, electrolyte, ligands, adsorbates, reaction products, and intermediates) and its structural, chemical, and electronic transformations as it adapts to the reaction conditions.
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Affiliation(s)
- Janis Timoshenko
- Department of Interface Science, Fritz-Haber Institute of the Max-Planck Society, 14195 Berlin, Germany
| | - Beatriz Roldan Cuenya
- Department of Interface Science, Fritz-Haber Institute of the Max-Planck Society, 14195 Berlin, Germany
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5
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Timoshenko J, Frenkel AI. “Inverting” X-ray Absorption Spectra of Catalysts by Machine Learning in Search for Activity Descriptors. ACS Catal 2019. [DOI: 10.1021/acscatal.9b03599] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Janis Timoshenko
- Department of Interface Science, Fritz-Haber-Institute of the Max Planck Society, 14195 Berlin, Germany
| | - Anatoly I. Frenkel
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11794, United States
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, United States
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6
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Timoshenko J, Duan Z, Henkelman G, Crooks RM, Frenkel AI. Solving the Structure and Dynamics of Metal Nanoparticles by Combining X-Ray Absorption Fine Structure Spectroscopy and Atomistic Structure Simulations. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2019; 12:501-522. [PMID: 30699037 DOI: 10.1146/annurev-anchem-061318-114929] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Extended X-ray absorption fine structure (EXAFS) spectroscopy is a premiere method for analysis of the structure and structural transformation of nanoparticles. Extraction of analytical information about the three-dimensional structure and dynamics of metal-metal bonds from EXAFS spectra requires special care due to their markedly non-bulk-like character. In recent decades, significant progress has been made in the first-principles modeling of structure and properties of nanoparticles. In this review, we summarize new approaches for EXAFS data analysis that incorporate particle structure modeling into the process of structural refinement.
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Affiliation(s)
- J Timoshenko
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11794, USA;
| | - Z Duan
- Department of Chemistry and Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712, USA
- Institute for Computational and Engineering Sciences, University of Texas at Austin, Austin, Texas 78712, USA
| | - G Henkelman
- Department of Chemistry and Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712, USA
- Institute for Computational and Engineering Sciences, University of Texas at Austin, Austin, Texas 78712, USA
| | - R M Crooks
- Department of Chemistry and Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712, USA
| | - A I Frenkel
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11794, USA;
- Division of Chemistry, Brookhaven National Laboratory, Upton, New York 11973, USA
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7
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Petkov V, Maswadeh Y, Vargas JA, Shan S, Kareem H, Wu ZP, Luo J, Zhong CJ, Shastri S, Kenesei P. Deviations from Vegard's law and evolution of the electrocatalytic activity and stability of Pt-based nanoalloys inside fuel cells by in operando X-ray spectroscopy and total scattering. NANOSCALE 2019; 11:5512-5525. [PMID: 30860531 DOI: 10.1039/c9nr01069f] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Catalysts for energy related applications, in particular metallic nanoalloys, readily undergo atomic-level changes during electrochemical reactions. The origin, dynamics and implications of the changes for the catalysts' activity inside fuel cells though are not well understood. This is largely because they are studied on model nanoalloy structures under controlled laboratory conditions. Here we use combined synchrotron X-ray spectroscopy and total scattering to study the dynamic behaviour of nanoalloys of Pt with 3d-transition metals as they function at the cathode of an operating proton exchange membrane fuel cell. Results show that the composition and atomic structure of the nanoalloys change profoundly, from the initial state to the active form and further along the cell operation. The electrocatalytic activity of the nanoalloys also changes. The rate and magnitude of the changes may be rationalized when the limits of traditional relationships used to connect the composition and structure of nanoalloys with their electrocatalytic activity and stability, such as Vegard's law, are recognized. In particular, deviations from the law inherent for Pt-3d metal nanoalloys can well explain their behaviour under operating conditions. Moreover, it appears that factors behind the remarkable electrocatalytic activity of Pt-3d metal nanoalloys, such as the large surface to unit volume ratio and "size misfit" of the constituent Pt and 3d-transition metal atoms, also contribute to their instability inside fuel cells. The new insight into the atomic-level evolution of nanoalloy electrocatalysts during their lifetime is likely to inspire new efforts to stabilize transient structure states beneficial to their activity and stability under operating conditions, if not synthesize them directly.
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Affiliation(s)
- Valeri Petkov
- Department of Physics and Science of Advanced Materials Program, Central Michigan University, Mt. Pleasant, Michigan 48859, USA.
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8
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Timoshenko J, Wrasman CJ, Luneau M, Shirman T, Cargnello M, Bare SR, Aizenberg J, Friend CM, Frenkel AI. Probing Atomic Distributions in Mono- and Bimetallic Nanoparticles by Supervised Machine Learning. NANO LETTERS 2019; 19:520-529. [PMID: 30501196 DOI: 10.1021/acs.nanolett.8b04461] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Properties of mono- and bimetallic metal nanoparticles (NPs) may depend strongly on their compositional, structural (or geometrical) attributes, and their atomic dynamics, all of which can be efficiently described by a partial radial distribution function (PRDF) of metal atoms. For NPs that are several nanometers in size, finite size effects may play a role in determining crystalline order, interatomic distances, and particle shape. Bimetallic NPs may also have different compositional distributions than bulk materials. These factors all render the determination of PRDFs challenging. Here extended X-ray absorption fine structure (EXAFS) spectroscopy, molecular dynamics simulations, and supervised machine learning (artificial neural-network) method are combined to extract PRDFs directly from experimental data. By applying this method to several systems of Pt and PdAu NPs, we demonstrate the finite size effects on the nearest neighbor distributions, bond dynamics, and alloying motifs in mono- and bimetallic particles and establish the generality of this approach.
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Affiliation(s)
- Janis Timoshenko
- Department of Materials Science and Chemical Engineering , Stony Brook University , Stony Brook , New York 11794 , United States
| | - Cody J Wrasman
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis , Stanford University , Stanford , California 94305 , United States
| | | | | | - Matteo Cargnello
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis , Stanford University , Stanford , California 94305 , United States
| | - Simon R Bare
- Stanford Synchrotron Radiation Lightsource , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States
| | | | | | - Anatoly I Frenkel
- Department of Materials Science and Chemical Engineering , Stony Brook University , Stony Brook , New York 11794 , United States
- Division of Chemistry , Brookhaven National Laboratory , Upton , New York 11973 , United States
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9
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Petkov V, Shastri S, Kim JW, Shan S, Luo J, Wu J, Zhong CJ. Application of differential resonant high-energy X-ray diffraction to three-dimensional structure studies of nanosized materials: A case study of Pt-Pd nanoalloy catalysts. ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES 2018; 74:553-566. [PMID: 30182942 DOI: 10.1107/s2053273318009282] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 06/27/2018] [Indexed: 11/10/2022]
Abstract
Atoms in many of the increasingly complex nanosized materials of interest to science and technology do not necessarily occupy the vertices of Bravais lattices. The atomic scale structure of such materials is difficult to determine by traditional X-ray diffraction and so their functional properties remain difficult to optimize by rational design. Here, the three-dimensional structure of PtxPd100-x nanoalloy particles is determined, where x = 0, 14, 36, 47, 64 and 100, by a non-traditional technique involving differential resonant high-energy X-ray diffraction experiments conducted at the K edge of Pt and Pd. The technique is coupled with three-dimensional modeling guided by the experimental total and element-specific atomic pair distribution functions. Furthermore, using DFT (density functional theory) calculation based on the positions of atoms in the obtained three-dimensional structure models, the catalytic performance of Pt-Pd particles is explained. Thus, differential resonant high-energy X-ray diffraction is shown to be an excellent tool for three-dimensional structure studies of nanosized materials. The experimental and modeling procedures are described in good detail, to facilitate their wider usage.
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Affiliation(s)
- Valeri Petkov
- Department of Physics, Central Michigan University, Mt Pleasant, Michigan 48859, USA
| | - Sarvjit Shastri
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Jong Woo Kim
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Shiyao Shan
- Department of Chemistry, State University of New York, Binghamton, New York 13902, USA
| | - Jin Luo
- Department of Chemistry, State University of New York, Binghamton, New York 13902, USA
| | - Jinfang Wu
- Department of Chemistry, State University of New York, Binghamton, New York 13902, USA
| | - Chuan Jian Zhong
- Department of Chemistry, State University of New York, Binghamton, New York 13902, USA
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10
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Young MJ, Bedford NM, Jiang N, Lin D, Dai L. In situ electrochemical high-energy X-ray diffraction using a capillary working electrode cell geometry. JOURNAL OF SYNCHROTRON RADIATION 2017; 24:787-795. [PMID: 28664886 DOI: 10.1107/s1600577517006282] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 04/26/2017] [Indexed: 06/07/2023]
Abstract
The ability to generate new electrochemically active materials for energy generation and storage with improved properties will likely be derived from an understanding of atomic-scale structure/function relationships during electrochemical events. Here, the design and implementation of a new capillary electrochemical cell designed specifically for in situ high-energy X-ray diffraction measurements is described. By increasing the amount of electrochemically active material in the X-ray path while implementing low-Z cell materials with anisotropic scattering profiles, an order of magnitude enhancement in diffracted X-ray signal over traditional cell geometries for multiple electrochemically active materials is demonstrated. This signal improvement is crucial for high-energy X-ray diffraction measurements and subsequent Fourier transformation into atomic pair distribution functions for atomic-scale structural analysis. As an example, clear structural changes in LiCoO2 under reductive and oxidative conditions using the capillary cell are demonstrated, which agree with prior studies. Accurate modeling of the LiCoO2 diffraction data using reverse Monte Carlo simulations further verifies accurate background subtraction and strong signal from the electrochemically active material, enabled by the capillary working electrode geometry.
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Affiliation(s)
- Matthias J Young
- Applied Chemicals and Materials Division, National Institute of Standards and Technology, Boulder, CO 80305, USA
| | - Nicholas M Bedford
- Applied Chemicals and Materials Division, National Institute of Standards and Technology, Boulder, CO 80305, USA
| | - Naisheng Jiang
- Center of Advanced Science and Engineering for Carbon (Case4Carbon), Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Deqing Lin
- Center of Advanced Science and Engineering for Carbon (Case4Carbon), Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Liming Dai
- Center of Advanced Science and Engineering for Carbon (Case4Carbon), Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
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11
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Timoshenko J, Keller KR, Frenkel AI. Determination of bimetallic architectures in nanometer-scale catalysts by combining molecular dynamics simulations with x-ray absorption spectroscopy. J Chem Phys 2017; 146:114201. [DOI: 10.1063/1.4978500] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
- Janis Timoshenko
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11794, USA
| | - Kayla R. Keller
- Mathematics Department, Bowdoin College, Brunswick, Maine 04011, USA
| | - Anatoly I. Frenkel
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11794, USA
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12
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Timoshenko J, Frenkel AI. Probing structural relaxation in nanosized catalysts by combining EXAFS and reverse Monte Carlo methods. Catal Today 2017. [DOI: 10.1016/j.cattod.2016.05.049] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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13
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Candelaria SL, Bedford NM, Woehl TJ, Rentz NS, Showalter AR, Pylypenko S, Bunker BA, Lee S, Reinhart B, Ren Y, Ertem SP, Coughlin EB, Sather NA, Horan JL, Herring AM, Greenlee LF. Multi-Component Fe–Ni Hydroxide Nanocatalyst for Oxygen Evolution and Methanol Oxidation Reactions under Alkaline Conditions. ACS Catal 2016. [DOI: 10.1021/acscatal.6b02552] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Stephanie L. Candelaria
- Applied
Chemicals and Materials Division, National Institute of Standards and Technology, Boulder, Colorado 80305, United States
| | - Nicholas M. Bedford
- Applied
Chemicals and Materials Division, National Institute of Standards and Technology, Boulder, Colorado 80305, United States
| | - Taylor J. Woehl
- Applied
Chemicals and Materials Division, National Institute of Standards and Technology, Boulder, Colorado 80305, United States
| | - Nikki S. Rentz
- Applied
Chemicals and Materials Division, National Institute of Standards and Technology, Boulder, Colorado 80305, United States
| | - Allison R. Showalter
- Department
of Physics, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Svitlana Pylypenko
- Department
of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Bruce A. Bunker
- Department
of Physics, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Sungsik Lee
- X-Ray
Sciences Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Benjamin Reinhart
- X-Ray
Sciences Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Yang Ren
- X-Ray
Sciences Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - S. Piril Ertem
- Department
of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - E. Bryan Coughlin
- Department
of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Nicholas A. Sather
- Department
of Chemical and Biological Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - James L. Horan
- Department
of Chemical and Biological Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Andrew M. Herring
- Department
of Chemical and Biological Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Lauren F. Greenlee
- Applied
Chemicals and Materials Division, National Institute of Standards and Technology, Boulder, Colorado 80305, United States
- Ralph
E. Martin Department of Chemical Engineering, University of Arkansas, Fayetteville, Arkansas 72701, United States
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14
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Petkov V, Prasai B, Shan S, Ren Y, Wu J, Cronk H, Luo J, Zhong CJ. Structural dynamics and activity of nanocatalysts inside fuel cells by in operando atomic pair distribution studies. NANOSCALE 2016; 8:10749-10767. [PMID: 27160891 DOI: 10.1039/c6nr01112h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Here we present the results from a study aimed at clarifying the relationship between the atomic structure and activity of nanocatalysts for chemical reactions driving fuel cells, such as the oxygen reduction reaction (ORR). In particular, using in operando high-energy X-ray diffraction (HE-XRD) we tracked the evolution of the atomic structure and activity of noble metal-transition metal (NM-TM) nanocatalysts for ORR as they function at the cathode of a fully operational proton exchange membrane fuel cell (PEMFC). Experimental HE-XRD data were analysed in terms of atomic pair distribution functions (PDFs) and compared to the current output of the PEMFC, which was also recorded during the experiments. The comparison revealed that under actual operating conditions, NM-TM nanocatalysts can undergo structural changes that differ significantly in both length-scale and dynamics and so can suffer losses in their ORR activity that differ significantly in both character and magnitude. Therefore we argue that strategies for reducing ORR activity losses should implement steps for achieving control not only over the length but also over the time-scale of the structural changes of NM-TM NPs that indeed occur during PEMFC operation. Moreover, we demonstrate how such a control can be achieved and thereby the performance of PEMFCs improved considerably. Last but not least, we argue that the unique capabilities of in operando HE-XRD coupled to atomic PDF analysis to characterize active nanocatalysts inside operating fuel cells both in a time-resolved manner and with atomic level resolution, i.e. in 4D, can serve well the ongoing search for nanocatalysts that deliver more with less platinum.
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Affiliation(s)
- Valeri Petkov
- Department of Physics, Central Michigan University, Mt. Pleasant, Michigan 48858, USA.
| | - Binay Prasai
- Department of Physics, Central Michigan University, Mt. Pleasant, Michigan 48858, USA.
| | - Shiyao Shan
- Department of Chemistry, State University of New York at Binghamton, New York 13902, USA.
| | - Yang Ren
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Jinfang Wu
- Department of Chemistry, State University of New York at Binghamton, New York 13902, USA.
| | - Hannah Cronk
- Department of Chemistry, State University of New York at Binghamton, New York 13902, USA.
| | - Jin Luo
- Department of Chemistry, State University of New York at Binghamton, New York 13902, USA.
| | - Chuan-Jian Zhong
- Department of Chemistry, State University of New York at Binghamton, New York 13902, USA.
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