1
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Hao T, Wei L, Jiang J, Zhou Q, Liu H. Microscopic Mechanism for Further NO Heterogeneous Reduction by Potassium-Doped Biochar: A DFT Study. J Phys Chem A 2024; 128:3370-3386. [PMID: 38652083 DOI: 10.1021/acs.jpca.3c08398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Biomass reburning is an efficient and low-cost way to control nitric oxide (NO), and the abundant potassium (K) element in biomass affects the heterogeneous reaction between NO and biochar. Due to the incomplete simulation of the NO heterogeneous reduction reaction pathway at the molecular level and the unclear catalytic effect of K element in biochar, further research is needed on the possible next reaction and the influencing mechanism of the element. After the products of the existing reaction pathways are referenced, two reasonably simplified biochar structural models are selected as the basic reactants to study the microscopic mechanism for further NO heterogeneous reduction on the biochar surface before and after doping with the K atom based on density functional theory. In studying the two further NO heterogeneous reduction reaction pathways, we find that the carbon monoxide (CO) molecule fragment protrudes from the surface of biochar models with the desorption of N2 at the TS4 transition state, and the two edge types of biochar product models obtained by simulation calculation are Klein edge and ac56 edge observed in the experiment. In studying the catalytic effect of potassium in biochar, we find that the presence of K increases the heat release of adsorption of NO molecules, reduces the energy barrier of the rate-determining step in the nitrogen (N2) generation and desorption process (by 50.88 and 69.97%), and hinders the CO molecule from desorbing from the biochar model surface. Thermodynamic and kinetic analyses also confirm its influence. The study proves that the heterogeneous reduction reaction of four NO molecules on the surface of biochar completes the whole reaction process and provides a basic theoretical basis for the emission of nitrogen oxides (NOx) during biomass reburning.
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Affiliation(s)
- Tong Hao
- School of Energy and Environment, Shenyang Aerospace University, Shenyang 110136, China
| | - Lihong Wei
- School of Energy and Environment, Shenyang Aerospace University, Shenyang 110136, China
| | - Jinyuan Jiang
- Research Center of Environmental Pollution Control Technology, Chinese Research Academy of Environment Sciences, Beijing 100012, China
| | - Qian Zhou
- School of Energy and Environment, Shenyang Aerospace University, Shenyang 110136, China
| | - Hui Liu
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
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2
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Shil S, Bhattacharya D, Misra A, Bytautas L. Antiaromatic Molecules as Magnetic Couplers: A Computational Quest. J Phys Chem A 2024; 128:815-828. [PMID: 38267395 PMCID: PMC10860145 DOI: 10.1021/acs.jpca.3c05784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 12/28/2023] [Accepted: 01/03/2024] [Indexed: 01/26/2024]
Abstract
In this study, we investigate a set of organic diradical structures in which two oxo-verdazyl radicals are selected as radical spin centers that are connected (coupled) via six coupler molecules (CM), resulting in various magnetic (ferromagnetic (FM) or antiferromagnetic (AFM)) characteristics, as reflected by their exchange coupling constants (J). We have designed 12 diradicals with 6-antiaromatic couplers coupled with bis-oxo-verdazyl diradicals with meta-meta (m-m) and para-meta (p-m) positional connectivities. The nature of the magnetic coupling (ferromagnetic, nonmagnetic, or antiferromagnetic) and the magnitude of the exchange constant J depend on the type of coupler, the connecting point between each radical center and CM, the degree of aromaticity of the coupler, and the length of the through-bond distance between radical centers. The computed magnetic exchange coupling constants J for these diradicals at the B3LYP/6-311++G(d,p) and MN12SX/6-311++G(d,p) levels of theory are large for many of these structures, indicating strong ferromagnetic coupling (with positive J values). In some cases, magnetic couplings are observed with J > 1000 cm-1 (B3LYP/6-311++G(d,p)) and strong antiferromagnetic coupling (with negative J values) with J < -1000 cm-1 (B3LYP/6-311++G(d,p)). Similarly, in some cases, magnetic couplings are observed with J > 289 cm-1 (MN12SX/6-311++G(d,p)) and strong antiferromagnetic coupling (with negative J values) with J < -568 cm-1 (MN12SX/6-311++G(d,p)). Furthermore, while numerous studies have reported that the degree of aromaticity of molecular couplers often favors strong ferromagnetic coupling, displaying the high-spin character of diradicals in their ground states, the couplers chosen in this study are characterized as antiaromatic or nonaromatic. The current investigation provides evidence that, remarkably, antiaromatic couplers are able to enhance stability by favoring electronic diradical structures with very strong ferromagnetic coupling when the length of the through-bond distance and connectivity pattern between radical centers are selected in such a way that the FM coupling is optimized. The findings in this study offer new strategies in the design of novel organic materials with interesting magnetic properties for practical applications.
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Affiliation(s)
- Suranjan Shil
- Manipal
Centre for Natural Sciences (Centre of Excellence), Manipal Academy of Higher Education, Manipal 576104, India
| | | | - Anirban Misra
- Department
of Chemistry, University of North Bengal, Raja Rammohunpur, Siliguri 734013, India
| | - Laimutis Bytautas
- Department
of Chemistry, Galveston College, 4015 Avenue Q, Galveston, Texas 77550, United States
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3
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Boebinger MG, Brea C, Ding LP, Misra S, Olunloyo O, Yu Y, Xiao K, Lupini AR, Ding F, Hu G, Ganesh P, Jesse S, Unocic RR. The Atomic Drill Bit: Precision Controlled Atomic Fabrication of 2D Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2210116. [PMID: 36635517 DOI: 10.1002/adma.202210116] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 01/02/2023] [Indexed: 06/17/2023]
Abstract
The ability to deterministically fabricate nanoscale architectures with atomic precision is the central goal of nanotechnology, whereby highly localized changes in the atomic structure can be exploited to control device properties at their fundamental physical limit. Here, an automated, feedback-controlled atomic fabrication method is reported and the formation of 1D-2D heterostructures in MoS2 is demonstrated through selective transformations along specific crystallographic orientations. The atomic-scale probe of an aberration-corrected scanning transmission electron microscope (STEM) is used, and the shape and symmetry of the scan pathway relative to the sample orientation are controlled. The focused and shaped electron beam is used to reliably create Mo6 S6 nanowire (MoS-NW) terminated metallic-semiconductor 1D-2D edge structures within a pristine MoS2 monolayer with atomic precision. From these results, it is found that a triangular beam path aligned along the zig-zag sulfur terminated (ZZS) direction forms stable MoS-NW edge structures with the highest degree of fidelity without resulting in disordering of the surrounding MoS2 monolayer. Density functional theory (DFT) calculations and ab initio molecular dynamic simulations (AIMD) are used to calculate the energetic barriers for the most stable atomic edge structures and atomic transformation pathways. These discoveries provide an automated method to improve understanding of atomic-scale transformations while opening a pathway toward more precise atomic-scale engineering of materials.
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Affiliation(s)
- Matthew G Boebinger
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN, 37830, USA
| | - Courtney Brea
- Department of Chemistry and Biochemistry, Queens College, City University of New York, 65-30 Kissena Blvd, Flushing, NY, 11367, USA
| | - Li-Ping Ding
- Department of Physics, Shaanxi University of Science and Technology, Xi'an Weiyang University Park, Xi'an, Shaanxi Province, China
| | - Sudhajit Misra
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN, 37830, USA
| | - Olugbenga Olunloyo
- Department of Physics and Astronomy, University of Tennessee, 1408 Circle Dr, Knoxville, TN, 37996, USA
| | - Yiling Yu
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN, 37830, USA
- School of Physics and Technology, Wuhan University, Wuchang District, Wuhan, Hubei, 430072, China
| | - Kai Xiao
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN, 37830, USA
| | - Andrew R Lupini
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN, 37830, USA
| | - Feng Ding
- Centre for Multidimensional Carbon Materials, Institute for Basic Science, 50 UNIST-gil, Ulsan, 44919, South Korea
- School of Materials Science and Engineering, Ulsan Institute of Science and Technology, 50 UNIST-gil, Ulsan, 44919, South Korea
| | - Guoxiang Hu
- Department of Chemistry and Biochemistry, Queens College, City University of New York, 65-30 Kissena Blvd, Flushing, NY, 11367, USA
| | - Panchapakesan Ganesh
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN, 37830, USA
| | - Stephen Jesse
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN, 37830, USA
| | - Raymond R Unocic
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN, 37830, USA
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4
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Xavier NF, Bauerfeldt GF, Sacchi M. First-Principles Microkinetic Modeling Unravelling the Performance of Edge-Decorated Nanocarbons for Hydrogen Production from Methane. ACS APPLIED MATERIALS & INTERFACES 2023; 15:6951-6962. [PMID: 36700729 PMCID: PMC9923683 DOI: 10.1021/acsami.2c20937] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 01/12/2023] [Indexed: 06/17/2023]
Abstract
The doping of graphitic and nanocarbon structures with nonmetal atoms allows for the tuning of surface electronic properties and the generation of new active sites, which can then be exploited for several catalytic applications. In this work, we investigate the direct conversion of methane into H2 and C2Hx over Klein-type zigzag graphene edges doped with nitrogen, boron, phosphorus and silicon. We combine Density Functional Theory (DFT) and microkinetic modeling to systematically investigate the reaction network and determine the most efficient edge decoration. Among the four edge-decorated nanocarbons (EDNCs) investigated, N-EDNC presented an outstanding performance for H2 production at temperatures over 900 K, followed by P-EDNC, Si-EDNC and B-EDNC. The DFT and microkinetic analysis of the enhanced desorption rate of atomic hydrogen reveal the presence of an Eley-Rideal mechanism, in which P-EDNC showed higher activity for H2 production in this scenario. Coke deposition resistance in the temperature range between 900 and 1500 K was evaluated, and we compared the selectivity toward H2 and C2H4 production. The N-EDNC and P-EDNC active sites showed strong resistance to carbon poisoning, whereas Si-EDNC showed higher propensity to regenerate its active sites at temperatures over 1100 K. This work shows that decorated EDNCs are promising metal-free catalysts for methane conversion into H2 and short-length alkenes.
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Affiliation(s)
- Neubi F. Xavier
- School
of Chemistry and Chemical Engineering, University
of Surrey, GuildfordGU2 7XH, U.K.
| | - Glauco F. Bauerfeldt
- Instituto
de Química, Universidade Federal
Rural do Rio de Janeiro, CEP 23890-000Seropédica, Rio de Janeiro, Brazil
| | - Marco Sacchi
- School
of Chemistry and Chemical Engineering, University
of Surrey, GuildfordGU2 7XH, U.K.
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5
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Li D, Wang Y, Cui T, Ma Y, Ding F. Local Carbon Concentration Determines the Graphene Edge Structure. J Phys Chem Lett 2020; 11:3451-3457. [PMID: 32298587 DOI: 10.1021/acs.jpclett.0c00525] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Although the structures and properties of various graphene edges have attracted enormous attention, the underlying mechanism that determines the appearance of various edges is still unknown. Here, a global search of graphene edge structures is performed by using the particle swarm optimization algorithm. In addition to locating the most stable edges of graphene, two databases of graphene armchair and zigzag edge structures are built. Graphene edge self-passivation plays an important role in the stability of the edges of graphene, and self-passivated edge structures that contain both octagons and triangles are found for the first time. The obvious "apical dominance" feature of armchair edges is found. The appearance of the experimentally observed ac(56), ac(677), and Klein edges can be explained by the local carbon concentration. Additionally, the graphene edge database is also significant for the study of the open end of nanotubes or fullerenes.
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Affiliation(s)
- Da Li
- State Key Lab of Superhard Materials, College of Physics, Jilin University, Changchun 130012, P.R. China
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Yanchao Wang
- State Key Lab of Superhard Materials, College of Physics, Jilin University, Changchun 130012, P.R. China
| | - Tian Cui
- State Key Lab of Superhard Materials, College of Physics, Jilin University, Changchun 130012, P.R. China
- School of Physical Science and Technology, Ningbo University, Ningbo 315211, P.R. China
| | - Yanming Ma
- State Key Lab of Superhard Materials, College of Physics, Jilin University, Changchun 130012, P.R. China
| | - Feng Ding
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
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6
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Park HJ, Cha J, Choi M, Kim JH, Tay RY, Teo EHT, Park N, Hong S, Lee Z. One-dimensional hexagonal boron nitride conducting channel. SCIENCE ADVANCES 2020; 6:eaay4958. [PMID: 32181347 PMCID: PMC7060069 DOI: 10.1126/sciadv.aay4958] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 12/12/2019] [Indexed: 05/16/2023]
Abstract
Hexagonal boron nitride (hBN) is an insulating two-dimensional (2D) material with a large bandgap. Although known for its interfacing with other 2D materials and structural similarities to graphene, the potential use of hBN in 2D electronics is limited by its insulating nature. Here, we report atomically sharp twin boundaries at AA'/AB stacking boundaries in chemical vapor deposition-synthesized few-layer hBN. We find that the twin boundary is composed of a 6'6' configuration, showing conducting feature with a zero bandgap. Furthermore, the formation mechanism of the atomically sharp twin boundaries is suggested by an analogy with stacking combinations of AA'/AB based on the observations of extended Klein edges at the layer boundaries of AB-stacked hBN. The atomically sharp AA'/AB stacking boundary is promising as an ultimate 1D electron channel embedded in insulating pristine hBN. This study will provide insights into the fabrication of single-hBN electronic devices.
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Affiliation(s)
- Hyo Ju Park
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Janghwan Cha
- Department of Physics, Graphene Research Institute, and GRI-TPC International Research Center, Sejong University, Seoul 05006, Republic of Korea
| | - Min Choi
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jung Hwa Kim
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Roland Yingjie Tay
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
- Temasek Laboratories@NTU, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Edwin Hang Tong Teo
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Noejung Park
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Suklyun Hong
- Department of Physics, Graphene Research Institute, and GRI-TPC International Research Center, Sejong University, Seoul 05006, Republic of Korea
- Corresponding author. (Z.L.); (S.H.)
| | - Zonghoon Lee
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
- Corresponding author. (Z.L.); (S.H.)
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7
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Hopkinson DG, Zólyomi V, Rooney AP, Clark N, Terry DJ, Hamer M, Lewis DJ, Allen CS, Kirkland AI, Andreev Y, Kudrynskyi Z, Kovalyuk Z, Patanè A, Fal'ko VI, Gorbachev R, Haigh SJ. Formation and Healing of Defects in Atomically Thin GaSe and InSe. ACS NANO 2019; 13:5112-5123. [PMID: 30946569 DOI: 10.1021/acsnano.8b08253] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Two dimensional III-VI metal monochalcogenide materials, such as GaSe and InSe, are attracting considerable attention due to their promising electronic and optoelectronic properties. Here, an investigation of point and extended atomic defects formed in mono-, bi-, and few-layer GaSe and InSe crystals is presented. Using state-of-the-art scanning transmission electron microscopy, it is observed that these materials can form both metal and selenium vacancies under the action of the electron beam. Selenium vacancies are observed to be healable: recovering the perfect lattice structure in the presence of selenium or enabling incorporation of dopant atoms in the presence of impurities. Under prolonged imaging, multiple point defects are observed to coalesce to form extended defect structures, with GaSe generally developing trigonal defects and InSe primarily forming line defects. These insights into atomic behavior could be harnessed to synthesize and tune the properties of 2D post-transition-metal monochalcogenide materials for optoelectronic applications.
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Affiliation(s)
- David G Hopkinson
- National Graphene Institute , University of Manchester , Booth Street East , Manchester M13 9PL , United Kingdom
- School of Materials , University of Manchester , Oxford Road , Manchester M13 9PL , United Kingdom
| | - Viktor Zólyomi
- National Graphene Institute , University of Manchester , Booth Street East , Manchester M13 9PL , United Kingdom
- School of Physics and Astronomy , University of Manchester , Oxford Road , Manchester M13 9PL , United Kingdom
| | - Aidan P Rooney
- School of Materials , University of Manchester , Oxford Road , Manchester M13 9PL , United Kingdom
| | - Nick Clark
- National Graphene Institute , University of Manchester , Booth Street East , Manchester M13 9PL , United Kingdom
- School of Materials , University of Manchester , Oxford Road , Manchester M13 9PL , United Kingdom
| | - Daniel J Terry
- National Graphene Institute , University of Manchester , Booth Street East , Manchester M13 9PL , United Kingdom
- School of Physics and Astronomy , University of Manchester , Oxford Road , Manchester M13 9PL , United Kingdom
| | - Matthew Hamer
- National Graphene Institute , University of Manchester , Booth Street East , Manchester M13 9PL , United Kingdom
- School of Physics and Astronomy , University of Manchester , Oxford Road , Manchester M13 9PL , United Kingdom
| | - David J Lewis
- School of Materials , University of Manchester , Oxford Road , Manchester M13 9PL , United Kingdom
| | - Christopher S Allen
- Electron Physical Sciences Imaging Centre , Diamond Light Source Ltd. , Didcot , Oxfordshire OX11 0DE , United Kingdom
- Department of Materials , University of Oxford , Parks Road , Oxford OX1 3PH , United Kingdom
| | - Angus I Kirkland
- Electron Physical Sciences Imaging Centre , Diamond Light Source Ltd. , Didcot , Oxfordshire OX11 0DE , United Kingdom
- Department of Materials , University of Oxford , Parks Road , Oxford OX1 3PH , United Kingdom
| | - Yuri Andreev
- National Tomsk State Research University , 634050 Tomsk , Russian Federation
| | - Zakhar Kudrynskyi
- School of Physics and Astronomy , University of Nottingham , Nottingham NG7 2RD , United Kingdom
| | - Zakhar Kovalyuk
- Institute for Problems of Materials Science , National Academy of Sciences of Ukraine , Chernivtsi Branch, 58001 Chernivtsi , Ukraine
| | - Amalia Patanè
- School of Physics and Astronomy , University of Nottingham , Nottingham NG7 2RD , United Kingdom
| | - Vladimir I Fal'ko
- National Graphene Institute , University of Manchester , Booth Street East , Manchester M13 9PL , United Kingdom
- School of Physics and Astronomy , University of Manchester , Oxford Road , Manchester M13 9PL , United Kingdom
- Henry Royce Institute for Advanced Materials , Manchester M13 9PL , United Kingdom
| | - Roman Gorbachev
- National Graphene Institute , University of Manchester , Booth Street East , Manchester M13 9PL , United Kingdom
- School of Physics and Astronomy , University of Manchester , Oxford Road , Manchester M13 9PL , United Kingdom
- Henry Royce Institute for Advanced Materials , Manchester M13 9PL , United Kingdom
| | - Sarah J Haigh
- National Graphene Institute , University of Manchester , Booth Street East , Manchester M13 9PL , United Kingdom
- School of Materials , University of Manchester , Oxford Road , Manchester M13 9PL , United Kingdom
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8
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Tuček J, Błoński P, Ugolotti J, Swain AK, Enoki T, Zbořil R. Emerging chemical strategies for imprinting magnetism in graphene and related 2D materials for spintronic and biomedical applications. Chem Soc Rev 2018; 47:3899-3990. [PMID: 29578212 DOI: 10.1039/c7cs00288b] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Graphene, a single two-dimensional sheet of carbon atoms with an arrangement mimicking the honeycomb hexagonal architecture, has captured immense interest of the scientific community since its isolation in 2004. Besides its extraordinarily high electrical conductivity and surface area, graphene shows a long spin lifetime and limited hyperfine interactions, which favors its potential exploitation in spintronic and biomedical applications, provided it can be made magnetic. However, pristine graphene is diamagnetic in nature due to solely sp2 hybridization. Thus, various attempts have been proposed to imprint magnetic features into graphene. The present review focuses on a systematic classification and physicochemical description of approaches leading to equip graphene with magnetic properties. These include introduction of point and line defects into graphene lattices, spatial confinement and edge engineering, doping of graphene lattice with foreign atoms, and sp3 functionalization. Each magnetism-imprinting strategy is discussed in detail including identification of roles of various internal and external parameters in the induced magnetic regimes, with assessment of their robustness. Moreover, emergence of magnetism in graphene analogues and related 2D materials such as transition metal dichalcogenides, metal halides, metal dinitrides, MXenes, hexagonal boron nitride, and other organic compounds is also reviewed. Since the magnetic features of graphene can be readily masked by the presence of magnetic residues from synthesis itself or sample handling, the issue of magnetic impurities and correct data interpretations is also addressed. Finally, current problems and challenges in magnetism of graphene and related 2D materials and future potential applications are also highlighted.
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Affiliation(s)
- Jiří Tuček
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic.
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9
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Lin KI, Ho YH, Liu SB, Ciou JJ, Huang BT, Chen C, Chang HC, Tu CL, Chen CH. Atom-Dependent Edge-Enhanced Second-Harmonic Generation on MoS 2 Monolayers. NANO LETTERS 2018; 18:793-797. [PMID: 29327927 DOI: 10.1021/acs.nanolett.7b04006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Edge morphology and lattice orientation of single-crystal molybdenum disulfide (MoS2) monolayers, a transition metal dichalcogenide (TMD), possessing a triangular shape with different edges grown by chemical vapor deposition are characterized by atomic force microscopy and transmission electron microscopy. Multiphoton laser scanning microscopy is utilized to study one-dimensional atomic edges of MoS2 monolayers with localized midgap electronic states, which result in greatly enhanced optical second-harmonic generation (SHG). Microscopic S-zigzag edge and S-Mo Klein edge (bare Mo atoms protruding from a S-zigzag edge) terminations and the edge-atom dependent resonance energies can therefore be deduced based on SHG images. Theoretical calculations based on density functional theory clearly explain the lower energy of the S-zigzag edge states compared to the corresponding S-Mo Klein edge states. Characterization of the atomic-scale variation of edge-enhanced SHG is a step forward in this full-optical and high-yield technique of atomic-layer TMDs.
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Affiliation(s)
- Kuang-I Lin
- Center for Micro/Nano Science and Technology, National Cheng Kung University , Tainan 70101, Taiwan
| | - Yen-Hung Ho
- National Center for Theoretical Sciences and Department of Physics, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - Shu-Bai Liu
- Center for Micro/Nano Science and Technology, National Cheng Kung University , Tainan 70101, Taiwan
| | - Jian-Jhih Ciou
- Department of Automatic Control Engineering, Feng Chia University , Taichung 40724, Taiwan
| | - Bo-Ting Huang
- Center for Micro/Nano Science and Technology, National Cheng Kung University , Tainan 70101, Taiwan
| | - Christopher Chen
- Department of Electrical Engineering, University of California , Los Angeles, California 90095, United States
| | - Han-Ching Chang
- Department of Automatic Control Engineering, Feng Chia University , Taichung 40724, Taiwan
| | - Chien-Liang Tu
- Department of Automatic Control Engineering, Feng Chia University , Taichung 40724, Taiwan
| | - Chang-Hsiao Chen
- Department of Automatic Control Engineering, Feng Chia University , Taichung 40724, Taiwan
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10
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Zhao X, Fu D, Ding Z, Zhang YY, Wan D, Tan SJR, Chen Z, Leng K, Dan J, Fu W, Geng D, Song P, Du Y, Venkatesan T, Pantelides ST, Pennycook SJ, Zhou W, Loh KP. Mo-Terminated Edge Reconstructions in Nanoporous Molybdenum Disulfide Film. NANO LETTERS 2018; 18:482-490. [PMID: 29253330 DOI: 10.1021/acs.nanolett.7b04426] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The catalytic and magnetic properties of molybdenum disulfide (MoS2) are significantly enhanced by the presence of edge sites. One way to obtain a high density of edge sites in a two-dimensional (2D) film is by introducing porosity. However, the large-scale bottom-up synthesis of a porous 2D MoS2 film remains challenging and the correlation of growth conditions to the atomic structures of the edges is not well understood. Here, using molecular beam epitaxy, we prepare wafer-scale nanoporous MoS2 films under conditions of high Mo flux and study their catalytic and magnetic properties. Atomic-resolution electron microscopy imaging of the pores reveals two new types of reconstructed Mo-terminated edges, namely, a distorted 1T (DT) edge and the Mo-Klein edge. Nanoporous MoS2 films are magnetic up to 400 K, which is attributed to the presence of Mo-terminated edges with unpaired electrons, as confirmed by density functional theory calculation. The small hydrogen adsorption free energy at these Mo-terminated edges leads to excellent activity for the hydrogen evolution reaction.
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Affiliation(s)
- Xiaoxu Zhao
- Department of Chemistry and Centre for Advanced 2D Materials (CA2DM), National University of Singapore , 3 Science Drive 3, Singapore, 117543, Singapore
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore , 13 Centre for Life Sciences, #05-01, 28 Medical Drive, Singapore 117456, Singapore
| | - Deyi Fu
- Department of Chemistry and Centre for Advanced 2D Materials (CA2DM), National University of Singapore , 3 Science Drive 3, Singapore, 117543, Singapore
- SinBeRISE CREATE, National Research Foundation , CREATE Tower, 1 Create Way, Singapore 138602, Singapore
| | - Zijing Ding
- Department of Chemistry and Centre for Advanced 2D Materials (CA2DM), National University of Singapore , 3 Science Drive 3, Singapore, 117543, Singapore
| | - Yu-Yang Zhang
- School of Physical Sciences and CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences , Beijing 100049, China
- Department of Physics and Astronomy and Department of Electrical Engineering and Computer Science, Vanderbilt University , Nashville, Tennessee 37235, United States
| | - Dongyang Wan
- NUSNNI-NanoCore, National University of Singapore , 117411, Singapore
| | - Sherman J R Tan
- Department of Chemistry and Centre for Advanced 2D Materials (CA2DM), National University of Singapore , 3 Science Drive 3, Singapore, 117543, Singapore
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore , 13 Centre for Life Sciences, #05-01, 28 Medical Drive, Singapore 117456, Singapore
| | - Zhongxin Chen
- Department of Chemistry and Centre for Advanced 2D Materials (CA2DM), National University of Singapore , 3 Science Drive 3, Singapore, 117543, Singapore
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore , 13 Centre for Life Sciences, #05-01, 28 Medical Drive, Singapore 117456, Singapore
| | - Kai Leng
- Department of Chemistry and Centre for Advanced 2D Materials (CA2DM), National University of Singapore , 3 Science Drive 3, Singapore, 117543, Singapore
| | - Jiadong Dan
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore , 13 Centre for Life Sciences, #05-01, 28 Medical Drive, Singapore 117456, Singapore
- Department of Materials Science and Engineering, National University of Singapore , 9 Engineering Drive 1, 117575, Singapore
| | - Wei Fu
- Department of Chemistry and Centre for Advanced 2D Materials (CA2DM), National University of Singapore , 3 Science Drive 3, Singapore, 117543, Singapore
| | - Dechao Geng
- Department of Chemistry and Centre for Advanced 2D Materials (CA2DM), National University of Singapore , 3 Science Drive 3, Singapore, 117543, Singapore
| | - Peng Song
- Department of Chemistry and Centre for Advanced 2D Materials (CA2DM), National University of Singapore , 3 Science Drive 3, Singapore, 117543, Singapore
| | - Yonghua Du
- Institute of Chemical and Engineering Sciences , Agency for Science, Technology and Research, 1 Pesek Road, Jurong Island 627833, Singapore
| | - T Venkatesan
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore , 13 Centre for Life Sciences, #05-01, 28 Medical Drive, Singapore 117456, Singapore
- NUSNNI-NanoCore, National University of Singapore , 117411, Singapore
- Department of Materials Science and Engineering, National University of Singapore , 9 Engineering Drive 1, 117575, Singapore
- Department of Electrical and Computer Engineering, National University of Singapore , 9 Engineering Drive 1, 117575, Singapore
- Department of Physics, National University of Singapore , 2 Science Drive 3, 517551, Singapore
| | - Sokrates T Pantelides
- Department of Physics and Astronomy and Department of Electrical Engineering and Computer Science, Vanderbilt University , Nashville, Tennessee 37235, United States
| | - Stephen J Pennycook
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore , 13 Centre for Life Sciences, #05-01, 28 Medical Drive, Singapore 117456, Singapore
- Department of Materials Science and Engineering, National University of Singapore , 9 Engineering Drive 1, 117575, Singapore
| | - Wu Zhou
- School of Physical Sciences and CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences , Beijing 100049, China
| | - Kian Ping Loh
- Department of Chemistry and Centre for Advanced 2D Materials (CA2DM), National University of Singapore , 3 Science Drive 3, Singapore, 117543, Singapore
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11
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Souza ES, Scopel WL, Miwa RH. Probing the local interface properties at a graphene–MoSe2 in-plane lateral heterostructure: an ab initio study. Phys Chem Chem Phys 2018; 20:17952-17960. [DOI: 10.1039/c8cp02343c] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
We report a theoretical study of the local interface properties at a graphene–MoSe2 (G–MoSe2) in-plane lateral heterostructure.
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Affiliation(s)
- Everson S. Souza
- Departamento de Física
- Universidade Federal do Espírito Santo
- Vitória
- Brazil
| | - Wanderlã L. Scopel
- Departamento de Física
- Universidade Federal do Espírito Santo
- Vitória
- Brazil
| | - Roberto H. Miwa
- Instituto de Física
- Universidade Federal de Uberlândia
- Uberlândia
- Brazil
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12
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Dang JS, Wang WW, Zheng JJ, Nagase S, Zhao X. Formation of Stone-Wales edge: Multistep reconstruction and growth mechanisms of zigzag nanographene. J Comput Chem 2017; 38:2241-2247. [PMID: 28718989 DOI: 10.1002/jcc.24871] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 05/15/2017] [Accepted: 06/13/2017] [Indexed: 11/06/2022]
Abstract
Although the existence of Stone-Wales (5-7) defect at graphene edge has been clarified experimentally, theoretical study on the formation mechanism is still imperfect. In particular, the regioselectivity of multistep reactions at edge (self-reconstruction and growth with foreign carbon feedstock) is essential to understand the kinetic behavior of reactive boundaries but investigations are still lacking. Herein, by using finite-sized models, multistep reconstructions and carbon dimer additions of a bared zigzag edge are introduced using density functional theory calculations. The zigzag to 5-7 transformation is proved as a site-selective process to generate alternating 5-7 pairs sequentially and the first step with largest barrier is suggested as the rate-determining step. Conversely, successive C2 insertions on the active edge are calculated to elucidate the formation of 5-7 edge during graphene growth. A metastable intermediate with a triple sequentially fused pentagon fragment is proved as the key structure for 5-7 edge formation. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Jing-Shuang Dang
- Institute for Chemical Physics & Department of Chemistry, School of Science, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Wei-Wei Wang
- Institute for Chemical Physics & Department of Chemistry, School of Science, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Jia-Jia Zheng
- Institute for Chemical Physics & Department of Chemistry, School of Science, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Shigeru Nagase
- Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto, 606-8103, Japan
| | - Xiang Zhao
- Institute for Chemical Physics & Department of Chemistry, School of Science, Xi'an Jiaotong University, Xi'an, 710049, China
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13
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Wang S, Sawada H, Allen CS, Kirkland AI, Warner JH. Orientation dependent interlayer stacking structure in bilayer MoS 2 domains. NANOSCALE 2017; 9:13060-13068. [PMID: 28837199 DOI: 10.1039/c7nr03198j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We have studied the atomic structure of small secondary domains that nucleate on monolayer MoS2 grown by chemical vapour deposition (CVD), which form the basis of bilayer MoS2. The small secondary bilayer domains have a faceted geometry with three-fold symmetry and adopt two distinct orientations with 60° rotation relative to an underlying monolayer MoS2 single crystal sheet. The two distinct orientations are associated with the 2H and 3R stacking configuration for bilayer MoS2. Atomic resolution images have been recorded using annular dark field scanning transmission electron microscopy (ADF-STEM) that show the edge termination, lattice orientation and stacking sequence of the bilayer domains relative to the underlying monolayer MoS2. These results provide important insights that bilayer MoS2 growth from 60° rotated small nuclei on the surface of monolayer MoS2 could lead to defective boundaries when merged to form larger continuous bilayer regions and that pure AA' or AB bilayer stacking may be challenging unless from a single seed.
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Affiliation(s)
- Shanshan Wang
- Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK
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14
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Abstract
Recognition and manipulation of graphene edges enable the control of physical properties of graphene-based devices. Recently, the authors have identified a peptide that preferentially binds to graphene edges from a combinatorial peptide library. In this study, the authors examine the functional basis for the edge binding peptide using experimental and computational methods. The effect of amino acid substitution, sequence context, and solution pH value on the binding of the peptide to graphene has been investigated. The N-terminus glutamic acid residue plays a key role in recognizing and binding to graphene edges. The protonation, substitution, and positional context of the glutamic acid residue impact graphene edge-binding. Our findings provide insights into the binding mechanisms and the design of peptides for recognizing and functionalizing graphene edges.
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15
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Chen Q, Robertson AW, He K, Gong C, Yoon E, Kirkland AI, Lee GD, Warner JH. Elongated Silicon-Carbon Bonds at Graphene Edges. ACS NANO 2016; 10:142-149. [PMID: 26619146 DOI: 10.1021/acsnano.5b06050] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We study the bond lengths of silicon (Si) atoms attached to both armchair and zigzag edges using aberration corrected transmission electron microscopy with monochromation of the electron beam. An in situ heating holder is used to perform imaging of samples at 800 °C in order to reduce chemical etching effects that cause rapid structure changes of graphene edges at room temperature under the electron beam. We provide detailed bond length measurements for Si atoms both attached to edges and also as near edge substitutional dopants. Edge reconstruction is also involved with the addition of Si dopants. Si atoms bonded to the edge of graphene are compared to substitutional dopants in the bulk lattice and reveal reduced out-of-plane distortion and bond elongation. An extended linear array of Si atoms at the edge is found to be energy-favorable due to inter-Si interactions. These results provide detailed structural information about the Si-C bonds in graphene, which may have importance in future catalytic and electronic applications.
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Affiliation(s)
- Qu Chen
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
| | - Alex W Robertson
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
| | - Kuang He
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
| | - Chuncheng Gong
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
| | - Euijoon Yoon
- Department of Materials Science and Engineering, Seoul National University , Seoul 151-742, Korea
| | - Angus I Kirkland
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
| | - Gun-Do Lee
- Department of Materials Science and Engineering, Seoul National University , Seoul 151-742, Korea
| | - Jamie H Warner
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
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16
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Kim JS, Warner JH, Robertson AW, Kirkland AI. Formation of Klein Edge Doublets from Graphene Monolayers. ACS NANO 2015; 9:8916-8922. [PMID: 26284501 DOI: 10.1021/acsnano.5b02730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
With increasing possibilities for applications of graphene, it is essential to fully characterize the rich topological variations in graphene edge structures. Using aberration-corrected transmission electron microscopy, dangling carbon doublets at the edge of monolayer graphene crystals have been observed. Unlike the single-atom Klein edge often found at zigzag edges, these carbon dimers were observed in various edge structure environments, but most frequently on the more stable armchair edges. Observation of this Klein edge doublet over time reveals that its existence enhances the stability of armchair edges and is a route to atom abstraction on zigzag edges.
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Affiliation(s)
- Judy S Kim
- Department of Materials, University of Oxford , Parks Road, Oxford, OX13PH, U.K
| | - Jamie H Warner
- Department of Materials, University of Oxford , Parks Road, Oxford, OX13PH, U.K
| | - Alex W Robertson
- Department of Materials, University of Oxford , Parks Road, Oxford, OX13PH, U.K
| | - Angus I Kirkland
- Department of Materials, University of Oxford , Parks Road, Oxford, OX13PH, U.K
- Research Complex at Harwell (RCaH), Rutherford Appleton Laboratory Harwell , Didcot, Oxon, OX11 0FA, U.K
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17
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Ni B, Wang X. Face the Edges: Catalytic Active Sites of Nanomaterials. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2015; 2:1500085. [PMID: 27980960 PMCID: PMC5115441 DOI: 10.1002/advs.201500085] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 04/19/2015] [Indexed: 05/07/2023]
Abstract
Edges are special sites in nanomaterials. The atoms residing on the edges have different environments compared to those in other parts of a nanomaterial and, therefore, they may have different properties. Here, recent progress in nanomaterial fields is summarized from the viewpoint of the edges. Typically, edge sites in MoS2 or metals, other than surface atoms, can perform as active centers for catalytic reactions, so the method to enhance performance lies in the optimization of the edge structures. The edges of multicomponent interfaces present even more possibilities to enhance the activities of nanomaterials. Nanoframes and ultrathin nanowires have similarities to conventional edges of nanoparticles, the application of which as catalysts can help to reduce the use of costly materials. Looking beyond this, the edge structures of graphene are also essential for their properties. In short, the edge structure can influence many properties of materials.
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Affiliation(s)
- Bing Ni
- Department of Chemistry Tsinghua University Beijing 100084 P. R. China
| | - Xun Wang
- Department of Chemistry Tsinghua University Beijing 100084 P. R. China
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18
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Sorkin V, Zhang YW. The structure and elastic properties of phosphorene edges. NANOTECHNOLOGY 2015; 26:235707. [PMID: 25994387 DOI: 10.1088/0957-4484/26/23/235707] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We investigated the edge atomic structures and elastic properties of defect-free phosphorene nanoribbons (PNRs). Density functional tight binding simulations were used to optimize two main edge configurations: armchair (AC) and zigzag (ZZ). It was found that the energy relaxation of PNRs leads to the noticeable changes in edge atomic configurations. The effective width of the edge region, which includes all the atoms involved in the edge relaxation, was found to contain approximately three atomic rows near the edge for both AC and ZZ PNRs. We further extracted the edge stress and modulus for the ZZ and AC edges. Both the AC and ZZ edge stresses of PNRs are positive, indicating tensile stress at the edges. In addition, both the AC and ZZ edge moduli are positive. However, the edge elastic modulus and edge stress of ZZ PNRs are about three times larger than those of AC PNRs. Furthermore, we showed that the tensile edge stresses along ZZ and AC edges are able to cause distortion in freestanding phosphorene nanoribbons. Our results highlight the importance of accounting for edge stresses in the design and fabrication of PNRs.
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Affiliation(s)
- V Sorkin
- Institute of High Performance Computing, A*Star, 138632, Singapore
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19
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Skowron ST, Lebedeva IV, Popov AM, Bichoutskaia E. Energetics of atomic scale structure changes in graphene. Chem Soc Rev 2015; 44:3143-76. [DOI: 10.1039/c4cs00499j] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
An overview of theoretical and experimental studies concerned with energetics of atomic scale structure changes in graphene, including thermally activated and electron irradiation-induced processes.
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Affiliation(s)
| | - Irina V. Lebedeva
- Nano-Bio Spectroscopy Group and ETSF Scientific Development Centre
- Departamento de Física de Materiales
- Universidad del Pais Vasco UPV/EHU
- San Sebastian E-20018
- Spain
| | - Andrey M. Popov
- Institute for Spectroscopy of Russian Academy of Sciences
- Moscow 142190
- Russia
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