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Liu X, Pan Y, Zhao J, Wang Y, Ge M, Qian L, Zhang L, Gu L, Zhou D, Su D. Atomically Resolved Transition Pathways of Iron Redox. J Am Chem Soc 2024; 146:17487-17494. [PMID: 38865676 DOI: 10.1021/jacs.4c05309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
The redox transition between iron and its oxides is of the utmost importance in heterogeneous catalysis, biological metabolism, and geological evolution. The structural characteristics of this reaction may vary based on surrounding environmental conditions, giving rise to diverse physical scenarios. In this study, we explore the atomic-scale transformation of nanosized Fe3O4 under ambient-pressure H2 gas using in-situ environmental transmission electron microscopy. Our results reveal that the internal solid-state reactions dominated by iron diffusion are coupled with the surface reactions involving gaseous O or H species. During reduction, we observe two competitive reduction pathways, namely Fe3O4 → FeO → Fe and Fe3O4 → Fe. An intermediate phase with vacancy ordering is observed during the disproportionation reaction of Fe2+ → Fe0 + Fe3+, which potentially alleviates stress and facilitates ion migration. As the temperature decreases, an oxidation process occurs in the presence of environmental H2O and trace amounts of O2. A direct oxidation of Fe to Fe3O4 occurs in the absence of the FeO phase, likely corresponding to a change in the water vapor content in the atmosphere. This work elucidates a full dynamical scenario of iron redox under realistic conditions, which is critical for unraveling the intricate mechanisms governing the solid-solid and solid-gas reactions.
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Affiliation(s)
- Xiaozhi Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yue Pan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jianxiong Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yuhan Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mengshu Ge
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Lixiang Qian
- Center for Combustion Energy, School of Vehicle and Mobility, Tsinghua University, Beijing 100084, China
| | - Liang Zhang
- Center for Combustion Energy, School of Vehicle and Mobility, Tsinghua University, Beijing 100084, China
| | - Lin Gu
- Beijing National Center for Electron Microscopy and Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Dan Zhou
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- DENSsolutions B.V., Delft 2628 ZD, The Netherlands
| | - Dong Su
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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2
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Huang X, Perera IP, Shubhashish S, Suib SL. Unveiling Enhanced PEC Water Oxidation: Morphology Tuning and Interfacial Phase Change in α-Fe 2O 3@K-OMS-2 Branched Core-Shell Nanoarrays. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 38691761 DOI: 10.1021/acsami.4c03164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
A simple fabrication method that involves two steps of hydrothermal reaction has been demonstrated for the growth of α-Fe2O3@K-OMS-2 branched core-shell nanoarrays. Different reactant concentrations in the shell-forming step led to different morphologies in the resultant composites, denoted as 0.25 OC, 0.5 OC, and 1.0 OC. Both 0.25 OC and 0.5 OC formed perfect branched core-shell structures, with 0.5 OC possessing longer branches, which were observed by SEM and TEM. The core K-OMS-2 and shell α-Fe2O3 were confirmed by grazing incidence X-ray diffraction (GIXRD), EDS mapping, and atomic alignment from high-resolution STEM images. Further investigation with high-resolution HAADF-STEM, EELS, and XPS indicated the existence of an ultrathin layer of Mn3O4 sandwiched at the interface. All composite materials offered greatly enhanced photocurrent density at 1.23 VRHE, compared to the pristine Fe2O3 photoanode (0.33 mA/cm2), and sample 0.5 OC showed the highest photocurrent density of 2.81 mA/cm2. Photoelectrochemical (PEC) performance was evaluated for the samples by conducting linear sweep voltammetry (LSV), applied bias photo-to-current efficiency (ABPE), electrochemical impedance spectroscopy (EIS), incident-photo-to-current efficiency (IPCE), transient photocurrent responses, and stability tests. The charge separation and transfer efficiencies, together with the electrochemically active surface area, were also investigated. The significant enhancement in sample 0.5 OC is ascribed to the synergetic effect brought by the longer branches in the core-shell structure, the conductive K-OMS-2 core, and the formation of the Mn3O4 thin layer formed between the core and shell.
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Affiliation(s)
- Xueni Huang
- Department of Chemistry, University of Connecticut, U-3060, 55 North Eagleville Rd., Storrs, Connecticut 06269, United States
| | - Inosh P Perera
- Department of Chemistry, University of Connecticut, U-3060, 55 North Eagleville Rd., Storrs, Connecticut 06269, United States
| | - Shubhashish Shubhashish
- Department of Chemistry, University of Connecticut, U-3060, 55 North Eagleville Rd., Storrs, Connecticut 06269, United States
| | - Steven L Suib
- Department of Chemistry, University of Connecticut, U-3060, 55 North Eagleville Rd., Storrs, Connecticut 06269, United States
- Institute of Materials Science, University of Connecticut, 97 North Eagleville Rd., Storrs, Connecticut 06269, United States
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3
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Sun X, Wu D, Saidi WA, Zhu W, Yang WCD, House SD, Li M, Sharma R, Yang JC, Zhou G. Atomic Dynamics of Multi-Interfacial Migration and Transformations. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2305746. [PMID: 37941496 DOI: 10.1002/smll.202305746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 10/24/2023] [Indexed: 11/10/2023]
Abstract
Redox-induced interconversions of metal oxidation states typically result in multiple phase boundaries that separate chemically and structurally distinct oxides and suboxides. Directly probing such multi-interfacial reactions is challenging because of the difficulty in simultaneously resolving the multiple reaction fronts at the atomic scale. Using the example of CuO reduction in H2 gas, a reaction pathway of CuO → monoclinic m-Cu4 O3 → Cu2 O is demonstrated and identifies interfacial reaction fronts at the atomic scale, where the Cu2 O/m-Cu4 O3 interface shows a diffuse-type interfacial transformation; while the lateral flow of interfacial ledges appears to control the m-Cu4 O3 /CuO transformation. Together with atomistic modeling, it is shown that such a multi-interface transformation results from the surface-reaction-induced formation of oxygen vacancies that diffuse into deeper atomic layers, thereby resulting in the formation of the lower oxides of Cu2 O and m-Cu4 O3 , and activate the interfacial transformations. These results demonstrate the lively dynamics at the reaction fronts of the multiple interfaces and have substantial implications for controlling the microstructure and interphase boundaries by coupling the interplay between the surface reaction dynamics and the resulting mass transport and phase evolution in the subsurface and bulk.
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Affiliation(s)
- Xianhu Sun
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY, 13902, USA
| | - Dongxiang Wu
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY, 13902, USA
| | - Wissam A Saidi
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA, 15216, USA
| | - Wenhui Zhu
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY, 13902, USA
| | - Wei-Chang D Yang
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Stephen D House
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Meng Li
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Renu Sharma
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Judith C Yang
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Guangwen Zhou
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY, 13902, USA
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4
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Hu J, Zheng H, Li L, Chen G, Li K, Qi M, Zhang Y, Zhao P, Meng W, Jia S, Wang J. Probing the Atomistic Reaction Pathways in CuO/C Catalysts. NANO LETTERS 2023; 23:9367-9374. [PMID: 37807279 DOI: 10.1021/acs.nanolett.3c02651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
CuOx/C catalysts have been used in the selective catalytic reduction of NOx because of the exceptional low-temperature denitration (de-NOx) activity. A fundamental understanding of the reaction between CuO and C is critical for controlling the component of CuOx/C and thus optimizing the catalytic performance. In this study, a transmission electron microscope equipped with an in situ heating device was utilized to investigate the atomic-scale reaction between CuO and C. We report two reaction mechanisms relying on the volume ratio between C and CuO: (1) The reduction from CuO to Cu2O (when the ratio is < ∼31%); (2) the reduction of CuO into polycrystalline Cu (when the ratio is > ∼34%). The atomistic reduction pathway can be well interpreted by considering the diffusion of O vacancy through the first-principle calculations. The atomic-scale exploration of CuO/C offers ample prospects for the design of industrial de-NOx catalysts in the future.
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Affiliation(s)
- Jie Hu
- School of Physics and Technology, Center for Electron Microscopy, MOE Key Laboratory of Artificial Micro- and Nano-structures, and Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - He Zheng
- School of Physics and Technology, Center for Electron Microscopy, MOE Key Laboratory of Artificial Micro- and Nano-structures, and Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
- Wuhan University Shenzhen Research Institute, Shenzhen, Guangdong 518057, China
| | - Lei Li
- Core Facility of Wuhan University, Wuhan 430072, China
| | - Guoxujia Chen
- School of Physics and Technology, Center for Electron Microscopy, MOE Key Laboratory of Artificial Micro- and Nano-structures, and Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Kaixuan Li
- School of Physics and Technology, Center for Electron Microscopy, MOE Key Laboratory of Artificial Micro- and Nano-structures, and Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Meng Qi
- School of Physics and Technology, Center for Electron Microscopy, MOE Key Laboratory of Artificial Micro- and Nano-structures, and Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Ying Zhang
- Core Facility of Wuhan University, Wuhan 430072, China
| | - Peili Zhao
- School of Physics and Technology, Center for Electron Microscopy, MOE Key Laboratory of Artificial Micro- and Nano-structures, and Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Weiwei Meng
- School of Physics and Technology, Center for Electron Microscopy, MOE Key Laboratory of Artificial Micro- and Nano-structures, and Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Shuangfeng Jia
- School of Physics and Technology, Center for Electron Microscopy, MOE Key Laboratory of Artificial Micro- and Nano-structures, and Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Jianbo Wang
- School of Physics and Technology, Center for Electron Microscopy, MOE Key Laboratory of Artificial Micro- and Nano-structures, and Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
- Core Facility of Wuhan University, Wuhan 430072, China
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5
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Liu X, Pan Y, Zhou D, Su D. In Situ TEM Investigation on Redox Mechanisms of Transition Metal Oxides. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:1577-1578. [PMID: 37613881 DOI: 10.1093/micmic/ozad067.811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Xiaozhi Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Yue Pan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Dan Zhou
- DENSsolutions B.V., Delft ZD, The Netherlands
| | - Dong Su
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
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6
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Sun X, Zhu W, Wu D, Li C, Wang J, Zhu Y, Chen X, Boscoboinik JA, Sharma R, Zhou G. Surface-reaction induced structural oscillations in the subsurface. Nat Commun 2020; 11:305. [PMID: 31949160 PMCID: PMC6965640 DOI: 10.1038/s41467-019-14167-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 12/16/2019] [Indexed: 11/09/2022] Open
Abstract
Surface and subsurface are commonly considered as separate entities because of the difference in the bonding environment and are often investigated separately due to the experimental challenges in differentiating the surface and subsurface effects. Using in-situ atomic-scale transmission electron microscopy to resolve the surface and subsurface at the same time, we show that the hydrogen-CuO surface reaction results in structural oscillations in deeper atomic layers via the cycles of ordering and disordering of oxygen vacancies in the subsurface. Together with atomistic calculations, we show that the structural oscillations in the subsurface are induced by the hydrogen oxidation-induced cyclic loss of oxygen from the oxide surface. These results demonstrate the propagation of the surface reaction dynamics into the deeper layers in inducing nonstoichiometry in the subsurface and have significant implications in modulating various chemical processes involving surface-subsurface mass transport such as heterogeneous catalysis, oxidation, corrosion and carburization.
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Affiliation(s)
- Xianhu Sun
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY, 13902, USA
| | - Wenhui Zhu
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY, 13902, USA
| | - Dongxiang Wu
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY, 13902, USA
| | - Chaoran Li
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY, 13902, USA
| | - Jianyu Wang
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY, 13902, USA
| | - Yaguang Zhu
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY, 13902, USA
| | - Xiaobo Chen
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY, 13902, USA
| | | | - Renu Sharma
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Guangwen Zhou
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY, 13902, USA.
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7
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Chi H, Curnan MT, Li M, Andolina CM, Saidi WA, Veser G, Yang JC. In situ environmental TEM observation of two-stage shrinking of Cu2O islands on Cu(100) during methanol reduction. Phys Chem Chem Phys 2020; 22:2738-2742. [DOI: 10.1039/c9cp05831a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A distinct two-stage reduction of Cu2O islands under methanol is revealed via combined in situ ETEM, statistical analysis, and DFT calculations.
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Affiliation(s)
- Hao Chi
- Department of Chemical and Petroleum Engineering
- University of Pittsburgh
- Pittsburgh
- USA
| | - Matthew T. Curnan
- Department of Chemical and Petroleum Engineering
- University of Pittsburgh
- Pittsburgh
- USA
- Department of Mechanical Engineering and Materials Science
| | - Meng Li
- Department of Chemical and Petroleum Engineering
- University of Pittsburgh
- Pittsburgh
- USA
| | | | - Wissam A. Saidi
- Department of Mechanical Engineering and Materials Science
- University of Pittsburgh
- Pittsburgh
- USA
| | - Götz Veser
- Department of Chemical and Petroleum Engineering
- University of Pittsburgh
- Pittsburgh
- USA
- Center for Energy
| | - Judith C. Yang
- Department of Chemical and Petroleum Engineering
- University of Pittsburgh
- Pittsburgh
- USA
- Department of Physics and Astronomy
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8
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Qin C, Hou B, Wang J, Wang G, Ma Z, Jia L, Li D. Stabilizing Optimal Crystalline Facet of Cobalt Catalysts for Fischer-Tropsch Synthesis. ACS APPLIED MATERIALS & INTERFACES 2019; 11:33886-33893. [PMID: 31498584 DOI: 10.1021/acsami.9b10174] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Developing efficient catalysts with a stable optimal crystalline facet is highly promising yet challenging for the Fischer-Tropsch synthesis (FTS). Here, we demonstrate a coating strategy to fabricate a stable optimal cobalt-facet catalyst. The catalyst (Co@C-SiO2) is composed of a single crystalline core, a wrapped carbon layer, and an amorphous silica shell. The moderate metal-support interaction endowed by carbon, combining the confined effect of the silica shell, protects and maintains the single-crystal structure and optimal crystalline facet of the core, that is, Co(10-11). Due to the unique core-shell nanostructure and optimal cobalt facets, our Co@C-SiO2 catalyst shows a remarkable low methane selectivity (5.3%), high activity (TOF = 4.0 × 10-2 s-1), C5+ selectivity (88.9%), and more importantly, excellent stability (TOS = 168 h) in FTS.
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Affiliation(s)
- Chuan Qin
- State Key Laboratory of Coal Conversion , Institute of Coal Chemistry, Chinese Academy of Sciences , Taiyuan 030001 , Shanxi , PR China
- University of Chinese Academy of Sciences , Beijing 100049 , PR China
| | - Bo Hou
- State Key Laboratory of Coal Conversion , Institute of Coal Chemistry, Chinese Academy of Sciences , Taiyuan 030001 , Shanxi , PR China
| | - Jungang Wang
- State Key Laboratory of Coal Conversion , Institute of Coal Chemistry, Chinese Academy of Sciences , Taiyuan 030001 , Shanxi , PR China
| | - Gang Wang
- Max Planck Institute for Polymer Research , Ackermannweg 10 , 55128 Mainz , Germany
| | - Zhongyi Ma
- State Key Laboratory of Coal Conversion , Institute of Coal Chemistry, Chinese Academy of Sciences , Taiyuan 030001 , Shanxi , PR China
| | - Litao Jia
- State Key Laboratory of Coal Conversion , Institute of Coal Chemistry, Chinese Academy of Sciences , Taiyuan 030001 , Shanxi , PR China
| | - Debao Li
- State Key Laboratory of Coal Conversion , Institute of Coal Chemistry, Chinese Academy of Sciences , Taiyuan 030001 , Shanxi , PR China
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9
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Sun X, Zhu W, Wu D, Liu Z, Chen X, Yuan L, Wang G, Sharma R, Zhou G. Atomic-Scale Mechanism of Unidirectional Oxide Growth. ADVANCED FUNCTIONAL MATERIALS 2019; 30:https://doi.org/10.1002/adfm.201906504. [PMID: 33029110 PMCID: PMC7537547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/13/2023]
Abstract
A fundamental knowledge of the unidirectional growth mechanisms is required for precise control on size, shape, and thereby functionalities of nanostructures. The oxidation of many metals results in oxide nanowire growth with a bicrystal grain boundary along the axial direction. Using transmission electron microscopy that spatially and temporally resolves CuO nanowire growth during the oxidation of copper, here we provide direct evidence of the correlation between unidirectional crystal growth and bicrystal grain boundary diffusion. Based on atomic scale observations of the upward growth at the nanowire tip, oscillatory downward growth of atomic layers on the nanowire sidewall and the parabolic kinetics of lengthening, bicrystal grain boundary diffusion is the mechanism by which Cu ions are delivered from the nanowire root to the tip. Together with density-functional theory calculations, we further show that the asymmetry in the corner-crossing barriers promotes the unidirectional oxide growth by hindering the transport of Cu ions from the nanowire tip to the sidewall facets. We expect the broader applicability of these results in manipulating the growth of nanostructured oxides by controlling the bicrystal grain boundary structure that favors anisotropic diffusion for unidirectional, one-dimensional crystal growth for nanowires or isotropic diffusion for two-dimensional platelet growth.
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Affiliation(s)
- Xianhu Sun
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY 13902, USA
| | - Wenhui Zhu
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY 13902, USA
| | - Dongxiang Wu
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY 13902, USA
| | - Zhenyu Liu
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
| | - Xiaobo Chen
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY 13902, USA
| | - Lu Yuan
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY 13902, USA
| | - Guofeng Wang
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
| | - Renu Sharma
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Guangwen Zhou
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY 13902, USA
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10
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Sun X, Zhu W, Wu D, Liu Z, Chen X, Yuan L, Wang G, Sharma R, Zhou G. Atomic-Scale Mechanism of Unidirectional Oxide Growth. ADVANCED FUNCTIONAL MATERIALS 2019. [PMID: 33029110 DOI: 10.1002/adfm.201901722] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A fundamental knowledge of the unidirectional growth mechanisms is required for precise control on size, shape, and thereby functionalities of nanostructures. The oxidation of many metals results in oxide nanowire growth with a bicrystal grain boundary along the axial direction. Using transmission electron microscopy that spatially and temporally resolves CuO nanowire growth during the oxidation of copper, here we provide direct evidence of the correlation between unidirectional crystal growth and bicrystal grain boundary diffusion. Based on atomic scale observations of the upward growth at the nanowire tip, oscillatory downward growth of atomic layers on the nanowire sidewall and the parabolic kinetics of lengthening, bicrystal grain boundary diffusion is the mechanism by which Cu ions are delivered from the nanowire root to the tip. Together with density-functional theory calculations, we further show that the asymmetry in the corner-crossing barriers promotes the unidirectional oxide growth by hindering the transport of Cu ions from the nanowire tip to the sidewall facets. We expect the broader applicability of these results in manipulating the growth of nanostructured oxides by controlling the bicrystal grain boundary structure that favors anisotropic diffusion for unidirectional, one-dimensional crystal growth for nanowires or isotropic diffusion for two-dimensional platelet growth.
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Affiliation(s)
- Xianhu Sun
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY 13902, USA
| | - Wenhui Zhu
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY 13902, USA
| | - Dongxiang Wu
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY 13902, USA
| | - Zhenyu Liu
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
| | - Xiaobo Chen
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY 13902, USA
| | - Lu Yuan
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY 13902, USA
| | - Guofeng Wang
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
| | - Renu Sharma
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Guangwen Zhou
- Department of Mechanical Engineering & Materials Science and Engineering Program, State University of New York, Binghamton, NY 13902, USA
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11
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Side effects-avoided theranostics achieved by biodegradable magnetic silica-sealed mesoporous polymer-drug with ultralow leakage. Biomaterials 2018; 186:1-7. [DOI: 10.1016/j.biomaterials.2018.09.039] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 08/31/2018] [Accepted: 09/24/2018] [Indexed: 12/21/2022]
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12
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Yu J, Yuan W, Yang H, Xu Q, Wang Y, Zhang Z. Fast Gas-Solid Reaction Kinetics of Nanoparticles Unveiled by Millisecond In Situ Electron Diffraction at Ambient Pressure. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201806541] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Jian Yu
- State Key Laboratory of Silicon Materials; School of Materials Science and Engineering; Zhejiang University; Hangzhou 310027 China
| | - Wentao Yuan
- State Key Laboratory of Silicon Materials; School of Materials Science and Engineering; Zhejiang University; Hangzhou 310027 China
| | - Hangsheng Yang
- State Key Laboratory of Silicon Materials; School of Materials Science and Engineering; Zhejiang University; Hangzhou 310027 China
| | - Qiang Xu
- DENSsolutions; Informaticalaan 12 2628ZD Delft The Netherlands
| | - Yong Wang
- State Key Laboratory of Silicon Materials; School of Materials Science and Engineering; Zhejiang University; Hangzhou 310027 China
| | - Ze Zhang
- State Key Laboratory of Silicon Materials; School of Materials Science and Engineering; Zhejiang University; Hangzhou 310027 China
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13
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Fast Gas-Solid Reaction Kinetics of Nanoparticles Unveiled by Millisecond In Situ Electron Diffraction at Ambient Pressure. Angew Chem Int Ed Engl 2018; 57:11344-11348. [DOI: 10.1002/anie.201806541] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Indexed: 11/07/2022]
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14
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Chen X, Wu D, Zou L, Yin Q, Zhang H, Zakharov DN, Stach EA, Zhou G. In situ atomic-scale observation of inhomogeneous oxide reduction. Chem Commun (Camb) 2018; 54:7342-7345. [PMID: 29911221 DOI: 10.1039/c8cc03822h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We report in situ atomic-scale transmission electron microscopy observations of the surface dynamics during Cu2O reduction. We show inhomogeneous oxide reduction caused by the preferential adsorption of hydrogen at step edges that induces oxygen loss and destabilizes Cu atoms within the step edge, thereby resulting in the retraction motion of atomic steps at the oxide surface.
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Affiliation(s)
- Xiaobo Chen
- Program of Materials Science and Engineering, Department of Mechanical Engineering, State University of New York at Binghamton, NY 13902, USA.
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15
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Determination of atomic positions from time resolved high resolution transmission electron microscopy images. Ultramicroscopy 2018; 186:139-145. [DOI: 10.1016/j.ultramic.2017.12.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 12/20/2017] [Accepted: 12/27/2017] [Indexed: 11/21/2022]
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Zhang Z, Sheng L, Chen L, Zhang Z, Wang Y. Atomic-scale observation of pressure-dependent reduction dynamics of W 18O 49 nanowires using environmental TEM. Phys Chem Chem Phys 2017; 19:16307-16311. [PMID: 28608883 DOI: 10.1039/c7cp03071a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The real-time observation of structural evolution of materials can provide critical information for understanding their reduction mechanisms under different environments. Herein, we report the atomic-scale observation of the reduction dynamics of W18O49 nanowires (NWs) using environmental transmission electron microscopy. Intriguingly, the reduction pathway is found to be affected by oxygen pressure. Under high oxygen pressure (∼0.095 Pa), a W18O49 NW epitaxially transforms into a WO2 NW via mass transport across the interface between (010)W18O49 and (101)WO2. While under low oxygen pressure (∼0.0004 Pa), the transformation follows the sequence of W18O49(NW) → WO2(NW) → β-W(nanoparticles), which is identified as a new reduction pathway. These findings reveal the pressure-dependent reduction and a new transformation pathway, and extend our current understanding of the reduction dynamics of metal oxides.
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Affiliation(s)
- Zhengfei Zhang
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China.
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