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You R, Wu Z, Yu J, Wang F, Chen S, Han ZK, Yuan W, Yang H, Wang Y. Revealing Surface Restraint-Induced Hexagonal Pd Nanocrystals via In Situ Transmission Electron Microscopy. NANO LETTERS 2022; 22:4333-4339. [PMID: 35584407 DOI: 10.1021/acs.nanolett.2c00411] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Achieving metal nanocrystals with metastable phase draws much attention due to their anticipated fascinating properties, wheras it is still challenging because their polymorphism nature and phase transition mechanism remain elusive. Here, phase stability of face-centered cubic (fcc) Pd nanocrystals was studied via in situ spherical aberration (Cs)-corrected transmission electron microscopy (TEM). By constructing a well-defined Pd/C composite structure, Pd nanocrystals encapsulated by graphite, the dispersion process of fcc Pd was observed through a nucleation and growth process. Interestingly, Cs-corrected scanning TEM analysis demonstrated that the newly formed Pd nanocrystals could adopt a metastable hexagonal phase, which was considered challenging to obtain. Accordingly, formation mechanism of the hexagonal Pd nanocrystals was proposed, which involved the combined effect of two factors: (1) templating of graphite and (2) size effect. This work is expected to offer new insight into the polymorphism of Pd nanocrystals and pave the way for the future design of metastable metal nanomaterials.
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Affiliation(s)
- Ruiyang You
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Zhemin Wu
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Jian Yu
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Fei Wang
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Shiyuan Chen
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Zhong-Kang Han
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Wentao Yuan
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Hangsheng Yang
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Yong Wang
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
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Yoon J, Cao Z, Raju RK, Wang Y, Burnley R, Gellman AJ, Barati Farimani A, Ulissi ZW. Deep reinforcement learning for predicting kinetic pathways to surface reconstruction in a ternary alloy. MACHINE LEARNING: SCIENCE AND TECHNOLOGY 2021. [DOI: 10.1088/2632-2153/ac191c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Abstract
The majority of computational catalyst design focuses on the screening of material components and alloy composition to optimize selectivity and activity for a given reaction. However, predicting the metastability of the alloy catalyst surface at realistic operating conditions requires an extensive sampling of possible surface reconstructions and their associated kinetic pathways. We present CatGym, a deep reinforcement learning (DRL) environment for predicting the thermal surface reconstruction pathways and their associated kinetic barriers in crystalline solids under reaction conditions. The DRL agent iteratively changes the positions of atoms in the near-surface region to generate kinetic pathways to accessible local minima involving changes in the surface compositions. We showcase our agent by predicting the surface reconstruction pathways of a ternary Ni3Pd3Au2(111) alloy catalyst. Our results show that the DRL agent can not only explore more diverse surface compositions than the conventional minima hopping method, but also generate the kinetic surface reconstruction pathways. We further demonstrate that the kinetic pathway to a global minimum energy surface composition and its associated transition state predicted by our agent is in good agreement with the minimum energy path predicted by nudged elastic band calculations.
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Li C, Zhang L, Gong T, Cheng Y, Li L, Li L, Jia S, Qi Y, Wang J, Gao Y. Study of the Growth Mechanism of Solution-Synthesized Symmetric Tellurium Nanoflakes at Atomic Resolution. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2005801. [PMID: 33470501 DOI: 10.1002/smll.202005801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/20/2020] [Indexed: 06/12/2023]
Abstract
As a new member of 2D materials, 2D tellurium (Te) has recently attracted much attention due to its intriguing properties. Through hydrothermal processing, 2D Te with tunable thickness and size has been realized, and its growth mechanism has also been studied. However, the tailored growth of 2D Te nanoflakes with symmetrical morphologies and interfacial moiré fringes has never been reported. Here, 2D Te nanoflakes have been prepared using the hydrothermal method, and mirror-symmetrical shapes (including "V-shape," "heart-shape," and "paper airplane-shape") with obvious moiré fringes in the middle of the nanoflakes are observed. Comprehensive transmission electron microscopy (TEM) techniques are utilized for structural characterization of these nanoflakes, especially the moiré fringes in the symmetry axis region of the nanoflakes. The systematic analyses of the moiré fringes and the observation of obvious overlapping edges of the composing nanoflakes from the cross-sectional samples reveal the possible mechanism of morphological evolution for these symmetrical nanoflakes. These details may fill the research gap in the controllable growth of 2D Te nanomaterials, pave the way for the fabrication of 2D Te moiré superlattices and in-plane homojunctions, and promote their future versatile applications.
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Affiliation(s)
- Chen Li
- Center for Nanoscale Characterization & Devices, Wuhan National Laboratory for Optoelectronics and School of Physics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, China
| | - Lei Zhang
- Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, School of Materials Science and Engineering, Hubei University, Wuhan, Hubei, 430062, China
| | - Tian Gong
- Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, School of Materials Science and Engineering, Hubei University, Wuhan, Hubei, 430062, China
| | - Yongfa Cheng
- Center for Nanoscale Characterization & Devices, Wuhan National Laboratory for Optoelectronics and School of Physics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, China
| | - Luying Li
- Center for Nanoscale Characterization & Devices, Wuhan National Laboratory for Optoelectronics and School of Physics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, China
| | - Li Li
- Center for Nanoscale Characterization & Devices, Wuhan National Laboratory for Optoelectronics and School of Physics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, China
| | - Shuangfeng Jia
- Center for Electron Microscopy, MOE Key Laboratory of Artificial Micro- and Nano-Structures and the Institute for Advanced Studies, School of Physics and Technology, Wuhan University, Wuhan, Hubei, 430072, China
| | - Yajun Qi
- Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, School of Materials Science and Engineering, Hubei University, Wuhan, Hubei, 430062, China
| | - Jianbo Wang
- Center for Electron Microscopy, MOE Key Laboratory of Artificial Micro- and Nano-Structures and the Institute for Advanced Studies, School of Physics and Technology, Wuhan University, Wuhan, Hubei, 430072, China
| | - Yihua Gao
- Center for Nanoscale Characterization & Devices, Wuhan National Laboratory for Optoelectronics and School of Physics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, China
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Tang M, Yuan W, Ou Y, Li G, You R, Li S, Yang H, Zhang Z, Wang Y. Recent Progresses on Structural Reconstruction of Nanosized Metal Catalysts via Controlled-Atmosphere Transmission Electron Microscopy: A Review. ACS Catal 2020. [DOI: 10.1021/acscatal.0c03335] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Min Tang
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Wentao Yuan
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Yang Ou
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Guanxing Li
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Ruiyang You
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Songda Li
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Hangsheng Yang
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Ze Zhang
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Yong Wang
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
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Howie A. New instrumentation and cutting edge research. Ultramicroscopy 2017; 180:52-58. [PMID: 28258870 DOI: 10.1016/j.ultramic.2016.11.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 11/04/2016] [Accepted: 11/15/2016] [Indexed: 11/16/2022]
Abstract
Stimulated by Ondrej Krivanek's contributions, the complex interaction between research and innovations in the instrumentation for electron microscopy is discussed. Specific attention is given to aberration correction and to spectroscopy in both the valence region and at the energies of localised phonons or bond vibrations. Current thinking about projection imaging and dielectric excitation theory may be challenged. More significantly in the new fields of investigation opened up to them, electron microscopists will need to build closer relations, particularly with the photonics and scanning tunnelling microscopy communities. Further improvements in instrumentation could usefully be directed towards imaging and spectroscopy at higher scattering angles as well as the incorporation of other facilities such as photon stimulation and secondary electron imaging.
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Affiliation(s)
- A Howie
- Dept. of Physics, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, UK
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6
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Yuan W, Wang Y, Li H, Wu H, Zhang Z, Selloni A, Sun C. Real-Time Observation of Reconstruction Dynamics on TiO2(001) Surface under Oxygen via an Environmental Transmission Electron Microscope. NANO LETTERS 2016; 16:132-7. [PMID: 26652061 DOI: 10.1021/acs.nanolett.5b03277] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The surface atomic structure has a remarkable impact on the physical and chemical properties of metal oxides and has been studied extensively by scanning tunneling microscopy. However, acquiring real-time information on the formation and evolution of the surface structure remains a great challenge. Here we use environmental transmission electron microscopy to directly observe the stress-induced reconstruction dynamics on the (001) surface of anatase TiO2. Our in situ results unravel for the first time how the (1 × 4) reconstruction forms and how the metastable (1 × 3) and (1 × 5) patterns transform into the (1 × 4) surface stable structure. With the support of first-principles calculations, we find that the surface evolution is driven by both low coordinated atoms and surface stress. This work provides a complete picture of the structural evolution of TiO2(001) under oxygen atmosphere and paves the way for future studies of the reconstruction dynamics of other solid surfaces.
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Affiliation(s)
- Wentao Yuan
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, China
| | - Yong Wang
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, China
| | - Hengbo Li
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, China
| | - Hanglong Wu
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, China
| | - Ze Zhang
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, China
| | - Annabella Selloni
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| | - Chenghua Sun
- ARC Centre for Electromaterials Science, School of Chemistry, Monash University , Clayton, Victoria 3800, Australia
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7
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Zhu GZ, Botton GA. A "thickness series": weak signal extraction of ELNES in EELS spectra from surfaces. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2014; 20:649-657. [PMID: 24345376 DOI: 10.1017/s1431927613013676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We report a new simple but effective method to extract the weak surface signals from a "thickness series" of recorded electron energy-loss spectra. Using precise thickness measurements and energy-loss near-edge structures measured at increasing thicknesses, we are able to extract the surface and bulk components in the series. The electronic structure and bonding information from SrTiO3 (001) reconstructed surfaces have been successfully obtained by applying this approach. This approach can be applied to study many other cases including absorbed monolayers and beam-sensitive interfaces.
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Affiliation(s)
- Guo-zhen Zhu
- Department of Materials Science and Engineering,Canadian Centre for Electron Microscopy,McMaster University,1280 Main Street West,Hamilton,ON L8S 4M1,Canada
| | - Gianluigi A Botton
- Department of Materials Science and Engineering,Canadian Centre for Electron Microscopy,McMaster University,1280 Main Street West,Hamilton,ON L8S 4M1,Canada
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Wu J, Sheng Zhao Y, Hu H, Huang J, Zuo JM, Dravid VP. Construction of an organic crystal structural model based on combined electron and powder X-ray diffraction data and the charge flipping algorithm. Ultramicroscopy 2011; 111:812-6. [DOI: 10.1016/j.ultramic.2010.09.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 09/07/2010] [Accepted: 09/09/2010] [Indexed: 11/30/2022]
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Kilaas R, Marks LD, Own CS. EDM 1.0: Electron direct methods. Ultramicroscopy 2005; 102:233-7. [PMID: 15639355 DOI: 10.1016/j.ultramic.2004.10.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2004] [Revised: 09/30/2004] [Accepted: 10/12/2004] [Indexed: 11/24/2022]
Abstract
A computer program designed to provide a number of quantitative analysis tools for high-resolution imaging and electron diffraction data is described. The program includes basic image manipulation, both real space and reciprocal space image processing, Wiener-filtering, symmetry averaging, methods for quantification of electron diffraction patterns and two-dimensional direct methods. The program consists of a number of sub-programs written in a combination of C++, C and Fortran. It can be downloaded either as GNU source code or as binaries and has been compiled and verified on a wide range of platforms, both Unix based and PC's. Elements of the design philosophy as well as future possible extensions are described.
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Affiliation(s)
- R Kilaas
- National Center for Electron Microscopy, Lawrence Berkeley National Labs, Berkeley, CA, USA
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