1
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Gong Z, Xiang Q, Li K, Xu Z, Hu J, Ni Y, Sato S, Sun Z. Pentagon‐Containing
Doublet Graphene Fragments with
Edge‐Dependent
Spin/Charge Distribution. CHINESE J CHEM 2022. [DOI: 10.1002/cjoc.202200344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Zongcheng Gong
- Institute of Molecular Plus, Department of Chemistry Tianjin university 92 Weijin Road Tianjin 300072 China
| | - Qin Xiang
- Institute of Molecular Plus, Department of Chemistry Tianjin university 92 Weijin Road Tianjin 300072 China
| | - Ke Li
- Institute of Molecular Plus, Department of Chemistry Tianjin university 92 Weijin Road Tianjin 300072 China
| | - Zhuofan Xu
- Institute of Molecular Plus, Department of Chemistry Tianjin university 92 Weijin Road Tianjin 300072 China
| | - Jinlian Hu
- Institute of Molecular Plus, Department of Chemistry Tianjin university 92 Weijin Road Tianjin 300072 China
| | - Yong Ni
- Department of Chemistry Southern University of Science and Technology Shenzhen 518055 China
| | - Sota Sato
- Department of Applied Chemistry Integrated Molecular Structure Analysis Laboratory, Social Cooperation Program, The University of Tokyo
| | - Zhe Sun
- Institute of Molecular Plus, Department of Chemistry Tianjin university 92 Weijin Road Tianjin 300072 China
- Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192 China
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2
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Wang J, Zhang Y, Shen Y. Universal strategy using environment-friendly inorganic compounds for the preparation of porous carbon nitride for efficient photocatalytic hydrogen production and environmental remediation. NEW J CHEM 2021. [DOI: 10.1039/d0nj03506h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work, a facile strategy is proposed for the preparation of efficient porous CN for photocatalytic hydrogen production and environmental remediation.
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Affiliation(s)
- Jianhai Wang
- College of Materials Science and Engineering
- Nanjing Tech University
- Nanjing 211816
- China
| | - Yuanjian Zhang
- Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device
- Jiangsu Province Hi-Tech Key Laboratory for Bio-Medical Research
- School of Chemistry and Chemical Engineering
- Medical School
- Southeast University
| | - Yuesong Shen
- College of Materials Science and Engineering
- Nanjing Tech University
- Nanjing 211816
- China
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3
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Gubin SP, Koksharov YA, Ioni YV. Magnetism of Nanosized “Nonmagnetic” Materials; the Role of Defects (Review). RUSS J INORG CHEM+ 2021. [DOI: 10.1134/s0036023621010034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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4
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Xiang Q, Guo J, Xu J, Ding S, Li Z, Li G, Phan H, Gu Y, Dang Y, Xu Z, Gong Z, Hu W, Zeng Z, Wu J, Sun Z. Stable Olympicenyl Radicals and Their π-Dimers. J Am Chem Soc 2020; 142:11022-11031. [PMID: 32456437 DOI: 10.1021/jacs.0c02287] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An olympicenyl radical, a spin 1/2 hydrocarbon radical with C2v symmetry and uneven spin distribution, remains elusive despite the considerable theoretical research interest. Herein, we report syntheses of two air-stable olympicenyl radical derivatives, OR1 and OR2, with half-life times (τ1/2) in air-saturated solution of 7 days and 34 days. The high stability was ascribed to kinetic blocking of reactive sites with high spin densities. X-ray crystallographic analysis revealed unique 20-center-2-electron head-to-tail π-dimer structures with intermolecular distances shorter than the sum of van der Waals radius of carbon. The ground state of the π-dimers was found to be singlet, with singlet-triplet energy gaps estimated to be -2.34 kcal/mol and -3.28 kcal/mol for OR1 and OR2, respectively, by variable-temperature electron spin resonance (ESR) spectroscopy. The monomeric radical species were in equilibrium with the π-dimer in solution, and the optical and electrochemical properties of the monomers and π-dimers in solution were investigated by UV-vis-NIR spectroscopy and cyclic voltammetry, revealing a concentration-dependent nature. Theoretical calculations illustrated that upon formation of a π-dimer the local aromaticity of each monomer was enhanced, and spatial ring current between the monomers was present, which resulted in an increment of aromaticity of the interior of the π-dimer.
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Affiliation(s)
- Qin Xiang
- Institute of Molecular Plus, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Tianjin University, 92 Weijin Road, Tianjin 300072, China
| | - Jing Guo
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Center for Aggregation-Induced Emission, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Jun Xu
- Health Science Platform, Tianjin University, 92 Weijin Road, Tianjin 300072, China
| | - Shuaishuai Ding
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Zhaoyang Li
- School of Materials Science and Engineering, Nankai University, 38 Tongyan Road, Haihe Educational Park, Tianjin 300350, China
| | - Guangwu Li
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Hoa Phan
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Yanwei Gu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Yanfeng Dang
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Zhanqiang Xu
- Institute of Molecular Plus, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Tianjin University, 92 Weijin Road, Tianjin 300072, China
| | - Zongcheng Gong
- Institute of Molecular Plus, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Tianjin University, 92 Weijin Road, Tianjin 300072, China
| | - Wenping Hu
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China
| | - Zebing Zeng
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Center for Aggregation-Induced Emission, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Jishan Wu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Zhe Sun
- Institute of Molecular Plus, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Tianjin University, 92 Weijin Road, Tianjin 300072, China
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5
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6
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Greco C, Cosentino U, Pitea D, Moro G, Santangelo S, Patanè S, D'Arienzo M, Fiore M, Morazzoni F, Ruffo R. Role of the carbon defects in the catalytic oxygen reduction by graphite nanoparticles: a spectromagnetic, electrochemical and computational integrated approach. Phys Chem Chem Phys 2019; 21:6021-6032. [PMID: 30810130 DOI: 10.1039/c8cp07023g] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The chemical groups present at the surface of graphite have been thought for a long time to be mainly responsible for its catalytic activity in the oxygen reduction reaction. Recently, it was proposed that the surface defects of graphite also significantly contribute to promote this reaction. Although the behaviour of surface defects has been reported, only few comments have been dedicated to their involvement in the mechanism and the possible intermediate species in the oxygen reduction reaction. Herein, we aim to present a more detailed explanation of the catalytic activity of graphite particles based on the structure of their defects and their size. Structural, spectroscopic and magnetic investigation (X-ray diffraction, Raman and electron spin resonance) and electrochemical measurements were performed to describe the nature of the defects and their aptitude to transfer electrons. Computational description supplied precise details of the energy of the different defects and their ability to promote the reduction, also suggesting the structure of the intermediate adduct in the oxygen reduction. The results indicated that molecular oxygen preferentially interacts with graphite defects, which involve the π-electron system and accumulation of the spin density on the edges of the grains, in particular, on the zig-zag edges present on ball-milled graphite. This promotes the reactivity of this nanomaterial. Furthermore, the activation increases by decreasing the particle size.
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Affiliation(s)
- Claudio Greco
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, I-20126 Milano, Italy.
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7
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Nafday D, Fang H, Jena P, Saha-Dasgupta T. Boronated holey graphene: a case of 2D ferromagnetic metal. Phys Chem Chem Phys 2019; 21:21128-21135. [DOI: 10.1039/c9cp02936b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In search of new candidates for two-dimensional ferromagnets, we consider boronated monolayer holey graphene (C2B), akin to recently synthesized and extensively studied nitrogenated monolayer holey graphene (C2N).
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Affiliation(s)
- Dhani Nafday
- School of Mathematical and Computational Sciences
- Indian Association for the Cultivation of Science
- Kolkata 700 032
- India
| | - Hong Fang
- Department of Physics
- Virginia Commonwealth University
- Richmond
- USA
| | - Puru Jena
- Department of Physics
- Virginia Commonwealth University
- Richmond
- USA
| | - Tanusri Saha-Dasgupta
- School of Mathematical and Computational Sciences
- Indian Association for the Cultivation of Science
- Kolkata 700 032
- India
- Department of Condensed Matter Physics and Materials Science
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8
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Bleu Y, Bourquard F, Tite T, Loir AS, Maddi C, Donnet C, Garrelie F. Review of Graphene Growth From a Solid Carbon Source by Pulsed Laser Deposition (PLD). Front Chem 2018; 6:572. [PMID: 30560117 PMCID: PMC6284203 DOI: 10.3389/fchem.2018.00572] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 11/05/2018] [Indexed: 11/29/2022] Open
Abstract
Graphene is a remarkable two-dimensional (2D) material that is of great interest to both academia and industry. It has outstanding electrical and thermal conductivity and good mechanical behavior with promising applications in electronic devices, supercapacitors, batteries, composite materials, flexible transparent displays, solar cells, and sensors. Several methods have been used to produce either pristine graphene or doped graphene. These include chemical vapor deposition (CVD), mechanical exfoliation, decomposition of SiC, liquid-phase exfoliation, pulsed laser deposition (PLD). Among these methods, PLD, which is routinely used for growing complex oxide thin films has proved to be an alternative to the more widely reported CVD method for producing graphene thin films, because of its advantages. Here we review the synthesis of graphene using PLD. We describe recent progress in preparing pristine graphene and doped graphene by PLD, including deposition processes and characterization. The goal of this complete survey is to describe the advantages of using the technique for graphene growth. The review will also help researchers to better understand graphene synthesis using the PLD technique.
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Affiliation(s)
- Yannick Bleu
- Laboratoire Hubert Curien UMR 5516 CNRS, Université Jean Monnet, University of Lyon, Saint-Étienne, France
| | - Florent Bourquard
- Laboratoire Hubert Curien UMR 5516 CNRS, Université Jean Monnet, University of Lyon, Saint-Étienne, France
| | - Teddy Tite
- Laboratoire Hubert Curien UMR 5516 CNRS, Université Jean Monnet, University of Lyon, Saint-Étienne, France
| | - Anne-Sophie Loir
- Laboratoire Hubert Curien UMR 5516 CNRS, Université Jean Monnet, University of Lyon, Saint-Étienne, France
| | - Chirandjeevi Maddi
- Laboratoire Hubert Curien UMR 5516 CNRS, Université Jean Monnet, University of Lyon, Saint-Étienne, France
| | - Christophe Donnet
- Laboratoire Hubert Curien UMR 5516 CNRS, Université Jean Monnet, University of Lyon, Saint-Étienne, France
| | - Florence Garrelie
- Laboratoire Hubert Curien UMR 5516 CNRS, Université Jean Monnet, University of Lyon, Saint-Étienne, France
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9
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Zuzak R, Castro-Esteban J, Brandimarte P, Engelund M, Cobas A, Piątkowski P, Kolmer M, Pérez D, Guitián E, Szymonski M, Sánchez-Portal D, Godlewski S, Peña D. Building a 22-ring nanographene by combining in-solution and on-surface syntheses. Chem Commun (Camb) 2018; 54:10256-10259. [DOI: 10.1039/c8cc05353g] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A nanographene formed by the fusion of 22 benzene rings has been prepared by combining in-solution cycloaddition reactions and on-surface cyclodehydrogenations.
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10
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Multian VV, Kinzerskyi FE, Vakaliuk AV, Grishchenko LM, Diyuk VE, Boldyrieva OY, Kozhanov VO, Mischanchuk OV, Lisnyak VV, Gayvoronsky VY. Surface Response of Brominated Carbon Media on Laser and Thermal Excitation: Optical and Thermal Analysis Study. NANOSCALE RESEARCH LETTERS 2017; 12:146. [PMID: 28241670 PMCID: PMC5323332 DOI: 10.1186/s11671-017-1873-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 01/29/2017] [Indexed: 06/06/2023]
Abstract
The present study is objected to develop an analytical remote optical diagnostics of the functionalized carbons surface. Carbon composites with up to 1 mmol g-1 of irreversibly adsorbed bromine were produced by the room temperature plasma treatment of an activated carbon fabric (ACF) derived from polyacrylonitrile textile. The brominated ACF (BrACF) was studied by elastic optical scattering indicatrix analysis at wavelength 532 nm. The obtained data were interpreted within results of the thermogravimetric analysis, X-ray photoelectron spectroscopy and temperature programmed desorption mass spectrometry. The bromination dramatically reduces the microporosity producing practically non-porous material, while the incorporated into the micropores bromine induces the dielectric and structural impact on surface polarizability and conductivity due to the charging effect. We have found that the elastic optical scattering in proper solid angles in the forward and the backward hemispheres is sensitive to the kind of the bromine bonding, e.g., physical adsorption or chemisorption, and the bromination level, respectively, that can be utilized for the express remote fabrication control of the nanoscale carbons with given interfaces.
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Affiliation(s)
- Volodymyr V Multian
- Institute of Physics, National Academy of Science of Ukraine, Prospect Nauky 46, Kyiv, 03680, Ukraine.
| | - Fillip E Kinzerskyi
- Institute of Physics, National Academy of Science of Ukraine, Prospect Nauky 46, Kyiv, 03680, Ukraine
| | - Anna V Vakaliuk
- Taras Shevchenko National University of Kyiv, Chemical faculty, Volodymyrska Str. 62a, Kyiv, 01601, Ukraine
| | - Liudmyla M Grishchenko
- Taras Shevchenko National University of Kyiv, Chemical faculty, Volodymyrska Str. 62a, Kyiv, 01601, Ukraine
| | - Vitaliy E Diyuk
- Taras Shevchenko National University of Kyiv, Chemical faculty, Volodymyrska Str. 62a, Kyiv, 01601, Ukraine
| | - Olga Yu Boldyrieva
- Taras Shevchenko National University of Kyiv, Chemical faculty, Volodymyrska Str. 62a, Kyiv, 01601, Ukraine
| | - Vadim O Kozhanov
- Taras Shevchenko National University of Kyiv, Chemical faculty, Volodymyrska Str. 62a, Kyiv, 01601, Ukraine
| | - Oleksandr V Mischanchuk
- O.O. Chuiko Institute of Surface Chemistry, National Academy of Science of Ukraine, General Naumov Str. 17, Kyiv, 03164, Ukraine
| | - Vladyslav V Lisnyak
- Taras Shevchenko National University of Kyiv, Chemical faculty, Volodymyrska Str. 62a, Kyiv, 01601, Ukraine
| | - Volodymyr Ya Gayvoronsky
- Institute of Physics, National Academy of Science of Ukraine, Prospect Nauky 46, Kyiv, 03680, Ukraine
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11
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Paul JT, Singh AK, Dong Z, Zhuang H, Revard BC, Rijal B, Ashton M, Linscheid A, Blonsky M, Gluhovic D, Guo J, Hennig RG. Computational methods for 2D materials: discovery, property characterization, and application design. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:473001. [PMID: 29022886 DOI: 10.1088/1361-648x/aa9305] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The discovery of two-dimensional (2D) materials comes at a time when computational methods are mature and can predict novel 2D materials, characterize their properties, and guide the design of 2D materials for applications. This article reviews the recent progress in computational approaches for 2D materials research. We discuss the computational techniques and provide an overview of the ongoing research in the field. We begin with an overview of known 2D materials, common computational methods, and available cyber infrastructures. We then move onto the discovery of novel 2D materials, discussing the stability criteria for 2D materials, computational methods for structure prediction, and interactions of monolayers with electrochemical and gaseous environments. Next, we describe the computational characterization of the 2D materials' electronic, optical, magnetic, and superconducting properties and the response of the properties under applied mechanical strain and electrical fields. From there, we move on to discuss the structure and properties of defects in 2D materials, and describe methods for 2D materials device simulations. We conclude by providing an outlook on the needs and challenges for future developments in the field of computational research for 2D materials.
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Affiliation(s)
- J T Paul
- Department of Materials Science and Engineering, University of Florida, Gainesville, Fl 32611, United States of America
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12
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Lee D, Seo J. Magnetic frustration of graphite oxide. Sci Rep 2017; 7:44690. [PMID: 28327606 PMCID: PMC5361081 DOI: 10.1038/srep44690] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 02/13/2017] [Indexed: 11/24/2022] Open
Abstract
Delocalized π electrons in aromatic ring structures generally induce diamagnetism. In graphite oxide, however, π electrons develop ferromagnetism due to the unique structure of the material. The π electrons are only mobile in the graphitic regions of graphite oxide, which are dispersed and surrounded by sp3-hybridized carbon atoms. The spin-glass behavior of graphite oxide is corroborated by the frequency dependence of its AC susceptibility. The magnetic susceptibility data exhibit a negative Curie temperature, field irreversibility, and slow relaxation. The overall results indicate that magnetic moments in graphite oxide slowly interact and develop magnetic frustration.
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Affiliation(s)
- Dongwook Lee
- Department of Physics, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.,Physics and Applied Physics, School of Physical &Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Jiwon Seo
- Department of Physics, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.,Department of Physics and Applied Physics, Yonsei University, Seoul, 120-749, Korea
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13
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Santos RM, Vilaverde C, Cunha E, Paiva MC, Covas JA. Probing dispersion and re-agglomeration phenomena upon melt-mixing of polymer-functionalized graphite nanoplates. SOFT MATTER 2016; 12:77-86. [PMID: 26439171 DOI: 10.1039/c5sm01366f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A one-step melt-mixing method is proposed to study dispersion and re-agglomeration phenomena of the as-received and functionalized graphite nanoplates in polypropylene melts. Graphite nanoplates were chemically modified via 1,3-dipolar cycloaddition of an azomethine ylide and then grafted with polypropylene-graft-maleic anhydride. The effect of surface functionalization on the dispersion kinetics, nanoparticle re-agglomeration and interface bonding with the polymer is investigated. Nanocomposites with 2 or 10 wt% of as-received and functionalized graphite nanoplates were prepared in a small-scale prototype mixer coupled to a capillary rheometer. Samples were collected along the flow axis and characterized by optical microscopy, scanning electron microscopy and electrical conductivity measurements. The as-received graphite nanoplates tend to re-agglomerate upon stress relaxation of the polymer melt. The covalent attachment of a polymer to the nanoparticle surface enhances the stability of dispersion, delaying the re-agglomeration. Surface modification also improves interfacial interactions and the resulting composites presented improved electrical conductivity.
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Affiliation(s)
- R M Santos
- Institute for Polymers and Composites/I3N, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal.
| | - C Vilaverde
- Institute for Polymers and Composites/I3N, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal.
| | - E Cunha
- Institute for Polymers and Composites/I3N, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal.
| | - M C Paiva
- Institute for Polymers and Composites/I3N, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal.
| | - J A Covas
- Institute for Polymers and Composites/I3N, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal.
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14
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Dong G, Zhang Y, Pan Q, Qiu J. A fantastic graphitic carbon nitride (g-C3N4) material: Electronic structure, photocatalytic and photoelectronic properties. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2014. [DOI: 10.1016/j.jphotochemrev.2014.04.002] [Citation(s) in RCA: 646] [Impact Index Per Article: 64.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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15
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Gao D, Xue Q, Mao X, Xue M, Shi S, Xue D. Porous tin disulfide nanosheets with room temperature ferromagnetic nature. CrystEngComm 2014. [DOI: 10.1039/c4ce00764f] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Fujii S, Enoki T. Nanographene and graphene edges: electronic structure and nanofabrication. Acc Chem Res 2013; 46:2202-10. [PMID: 24383129 DOI: 10.1021/ar300120y] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Graphene can be referred to as an infinite polycyclic aromatic hydrocarbon (PAH) consisting of an infinite number of benzene rings fused together. However, at the nanoscale, nanographene's properties lie in between those of bulk graphene and large PAH molecules, and its electronic properties depend on the influence of the edges, which disrupt the infinite π-electron system. The resulting modulation of the electronic states depends on whether the nanographene edge is the armchair or zigzag type, corresponding to the two fundamental crystal axes. In this Account, we report the results of fabricating both types of edges in the nanographene system and characterizing their electronic properties using a scanning probe microscope. We first introduce the theoretical background to understand the two types of finite size effects on the electronic states of nanographene (i) the standing wave state and (ii) the edge state which correspond to the armchair and zigzag edges, respectively. Most importantly, characterizing the standing wave and edge states could play a crucial role in understanding the chemical reactivity, thermodynamic stability and magnetism of nanosized graphene--important knowledge in the design and realization of promising functionalized nanocarbon materials. In the second part, we present scanning probe microscopic characterization of both edge types to experimentally characterize the two electronic states. As predicted, we find the armchair-edged nanographene to have an energetically stable electronic pattern. The zigzag-edged nanographene shows a nonbonding (π radical) pattern, which is the source of the material's electronic and magnetic properties and its chemical activity. Precise control of the edge geometry is a practical requirement to control the electronic structure. We show that we can fabricate the energetically unstable zigzag edges using scanning probe manipulation techniques, and we discuss challenges in using these techniques for that purpose.
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Affiliation(s)
- Shintaro Fujii
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Toshiaki Enoki
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
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17
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Gourier D, Delpoux O, Binet L, Vezin H. Nuclear magnetic biosignatures in the carbonaceous matter of ancient cherts: comparison with carbonaceous meteorites. ASTROBIOLOGY 2013; 13:932-947. [PMID: 24093546 DOI: 10.1089/ast.2013.0971] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The search for organic biosignatures is motivated by the hope of understanding the conditions of emergence of life on Earth and the perspective of finding traces of extinct life in martian sediments. Paramagnetic radicals, which exist naturally in amorphous carbonaceous matter fossilized in Precambrian cherts, were used as local structural probes and studied by electron paramagnetic resonance (EPR) spectroscopy. The nuclear magnetic resonance transitions of elements inside and around these radicals were detected by monitoring the nuclear modulations of electron spin echo in pulsed EPR. We found that the carbonaceous matter of fossilized microorganisms with age up to 3.5 billion years gives specific nuclear magnetic signatures of hydrogen (¹H), carbon (¹³C), and phosphorus (³¹P) nuclei. We observed that these potential biosignatures of extinct life are found neither in the carbonaceous matter of carbonaceous meteorites (4.56 billion years), the most ancient objects of the Solar System, nor in any carbonaceous matter resulting from carbonization of organic and bioorganic precursors. These results indicate that these nuclear signatures are sensitive to thermal episodes and can be used for Archean cherts with metamorphism not higher than the greenschist facies.
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Affiliation(s)
- Didier Gourier
- 1 TGE Réseau National de RPE interdisciplinaire (RENARD, FR-CNRS 3443)
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18
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Tomai T, Tamura N, Honma I. One-Step Production of Anisotropically Etched Graphene Using Supercritical Water. ACS Macro Lett 2013; 2:794-798. [PMID: 35606982 DOI: 10.1021/mz400186t] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We developed a one-step method for production of anisotropically etched graphene using supercritical fluid (SCF). Anisotropic etching of a graphite substrate and dispersed graphite powder with Ag nanoparticles was conducted in supercritical water (SCW). Because of the exfoliation effect of SCF, graphene was isolated from the graphite simultaneously with the anisotropic etching. High-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy revealed the production of multilayer graphene exfoliated from the anisotropically etched graphite surface.
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Affiliation(s)
- Takaaki Tomai
- Institute of Multidisciplinary
Research for Advanced Materials, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Naoki Tamura
- Institute of Multidisciplinary
Research for Advanced Materials, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Itaru Honma
- Institute of Multidisciplinary
Research for Advanced Materials, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577, Japan
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Sun Z, Zeng Z, Wu J. Benzenoid Polycyclic Hydrocarbons with an Open-Shell Biradical Ground State. Chem Asian J 2013; 8:2894-904. [DOI: 10.1002/asia.201300560] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Indexed: 11/09/2022]
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20
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Matte HSSR, Maitra U, Kumar P, Govinda Rao B, Pramoda K, Rao CNR. Synthesis, Characterization, and Properties of Few-layer Metal Dichalcogenides and their Nanocomposites with Noble Metal Particles, Polyaniline, and Reduced Graphene Oxide. Z Anorg Allg Chem 2012. [DOI: 10.1002/zaac.201200283] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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21
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Deleuze MS, Huzak M, Hajgató B. Half-metallicity of graphene nanoribbons and related systems: a new quantum mechanical El Dorado for nanotechnologies... or a hype for materials scientists? J Mol Model 2012; 19:2699-714. [PMID: 22824949 DOI: 10.1007/s00894-012-1517-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 06/21/2012] [Indexed: 11/30/2022]
Abstract
In this work we discuss in some computational and analytical details the issue of half-metallicity in zig-zag graphene nanoribbons and nanoislands of finite width, i.e. the coexistence of metallic nature for electrons with one spin orientation and insulating nature for the electrons of opposite spin, which has been recently predicted from so-called first-principle calculations employing Density Functional Theory. It is mathematically demonstrated and computationally verified that, within the framework of non-relativistic and time-independent quantum mechanics, like the size-extensive spin-contamination to which it relates, half-metallicity is nothing else than a methodological artefact, due to a too approximate treatment of electron correlation in the electronic ground state.
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Affiliation(s)
- Michael S Deleuze
- Theoretical Chemistry and Molecular Modelling, Hasselt University, Agoralaan, Gebouw D, B-3590, Diepenbeek, Belgium.
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22
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Wei W, Qu X. Extraordinary physical properties of functionalized graphene. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2012; 8:2138-2151. [PMID: 22674906 DOI: 10.1002/smll.201200104] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 03/06/2012] [Indexed: 06/01/2023]
Abstract
Graphene has attracted much attention in recent years due to its extraordinary electronic, optical, magnetic, thermal, and mechanical properties. Despite continuing theoretical and experimental success, the unique physical properties of graphene remain underused and underappreciated. The key challenge in harnessing of the unique properties of graphene is the difficulty of reliable manipulation of well-dispersed graphene. Chemical and physical functionalization of graphene has become a focus of especial interest, because they can not only stabilize, but also induce new properties of graphene. This review summarizes the intriguing physical properties of chemically oxidized and noncovalently modified graphene, and graphene-based nanocomposites with polymer matrices or nanoparticles. Along with introducing the physical properties of functionalized graphene, their potential applications in diverse research areas are discussed.
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Affiliation(s)
- Weili Wei
- State Key Laboratory of Rare Earth Resource Utilization, Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China
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23
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Hao SJ, Takai K, Joly VLJ, Yokota K, Kiguchi M, Enoki T. Magnetic Properties and Interplay between Nanographene Host and Nitric Acid Guest in Nanographene-Based Nanoporous Carbon. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2012. [DOI: 10.1246/bcsj.20110300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Si-Jia Hao
- Department of Chemistry, Tokyo Institute of Technology
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24
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Sun Z, Ye Q, Chi C, Wu J. Low band gap polycyclic hydrocarbons: from closed-shell near infrared dyes and semiconductors to open-shell radicals. Chem Soc Rev 2012; 41:7857-89. [DOI: 10.1039/c2cs35211g] [Citation(s) in RCA: 512] [Impact Index Per Article: 42.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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25
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Huzak M, Deleuze MS, Hajgató B. Half-metallicity and spin-contamination of the electronic ground state of graphene nanoribbons and related systems: An impossible compromise? J Chem Phys 2011; 135:104704. [DOI: 10.1063/1.3626554] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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27
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Srivastava S, Gajbhiye NS. Carbogenic Nanodots: Photoluminescence and Room-Temperature Ferromagnetism. Chemphyschem 2011; 12:2624-32. [DOI: 10.1002/cphc.201100188] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 07/01/2011] [Indexed: 11/09/2022]
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28
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Levi MD, Sigalov S, Salitra G, Elazari R, Aurbach D. Assessing the Solvation Numbers of Electrolytic Ions Confined in Carbon Nanopores under Dynamic Charging Conditions. J Phys Chem Lett 2011; 2:120-124. [PMID: 26295530 DOI: 10.1021/jz1016922] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We propose herein a new reliable approach to assess solvation numbers of ions confined in carbon nanopores based on dynamic quartz crystal measurements. This was proved for the entire families of alkaline, alkaline-earth cations, and halogen anions. As-assessed hydration numbers appear in the sequence characteristic of a transition from the cosmotropic to a chaotropic-type behavior with the decrease of the ion's charge-to-size ratio. The information on the behavior of ions confined in nanometric space of different (especially charged) carbon materials is in high demand for the development of powerful supercapacitors, nanofiltration membranes, and chemical/biochemical sensors.
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Affiliation(s)
- Mikhael D Levi
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Sergey Sigalov
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Gregory Salitra
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Ran Elazari
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Doron Aurbach
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
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30
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Carbon–nitrogen nanorings and nanoribbons: a theoretical approach for altering the ground states of cyclacenes and polyacenes. MONATSHEFTE FUR CHEMIE 2010. [DOI: 10.1007/s00706-010-0398-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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31
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Rao CNR, Subrahmanyam KS, Ramakrishna Matte HSS, Abdulhakeem B, Govindaraj A, Das B, Kumar P, Ghosh A, Late DJ. A study of the synthetic methods and properties of graphenes. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2010; 11:054502. [PMID: 27877359 PMCID: PMC5090618 DOI: 10.1088/1468-6996/11/5/054502] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 10/27/2010] [Accepted: 08/10/2010] [Indexed: 05/24/2023]
Abstract
Graphenes with varying number of layers can be synthesized by using different strategies. Thus, single-layer graphene is prepared by micromechanical cleavage, reduction of single-layer graphene oxide, chemical vapor deposition and other methods. Few-layer graphenes are synthesized by conversion of nanodiamond, arc discharge of graphite and other methods. In this article, we briefly overview the various synthetic methods and the surface, magnetic and electrical properties of the produced graphenes. Few-layer graphenes exhibit ferromagnetic features along with antiferromagnetic properties, independent of the method of preparation. Aside from the data on electrical conductivity of graphenes and graphene-polymer composites, we also present the field-effect transistor characteristics of graphenes. Only single-layer reduced graphene oxide exhibits ambipolar properties. The interaction of electron donor and acceptor molecules with few-layer graphene samples is examined in detail.
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Affiliation(s)
- C N R Rao
- Chemistry and Physics of Materials Unit, International Centre for Materials Science, New Chemistry Unit and CSIR Centre of Excellence in Chemistry, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore 560 064, India
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - K S Subrahmanyam
- Chemistry and Physics of Materials Unit, International Centre for Materials Science, New Chemistry Unit and CSIR Centre of Excellence in Chemistry, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore 560 064, India
| | - H S S Ramakrishna Matte
- Chemistry and Physics of Materials Unit, International Centre for Materials Science, New Chemistry Unit and CSIR Centre of Excellence in Chemistry, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore 560 064, India
| | - B Abdulhakeem
- Chemistry and Physics of Materials Unit, International Centre for Materials Science, New Chemistry Unit and CSIR Centre of Excellence in Chemistry, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore 560 064, India
| | - A Govindaraj
- Chemistry and Physics of Materials Unit, International Centre for Materials Science, New Chemistry Unit and CSIR Centre of Excellence in Chemistry, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore 560 064, India
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Barun Das
- Chemistry and Physics of Materials Unit, International Centre for Materials Science, New Chemistry Unit and CSIR Centre of Excellence in Chemistry, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore 560 064, India
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Prashant Kumar
- Chemistry and Physics of Materials Unit, International Centre for Materials Science, New Chemistry Unit and CSIR Centre of Excellence in Chemistry, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore 560 064, India
| | - Anupama Ghosh
- Chemistry and Physics of Materials Unit, International Centre for Materials Science, New Chemistry Unit and CSIR Centre of Excellence in Chemistry, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore 560 064, India
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Dattatray J Late
- Chemistry and Physics of Materials Unit, International Centre for Materials Science, New Chemistry Unit and CSIR Centre of Excellence in Chemistry, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore 560 064, India
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32
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Xiu Y, Gao Q, Li GD, Wang KX, Chen JS. Preparation and Tunable Photoluminescence of Carbogenic Nanoparticles Confined in a Microporous Magnesium-Aluminophosphate. Inorg Chem 2010; 49:5859-67. [DOI: 10.1021/ic1000039] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yang Xiu
- School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Qian Gao
- School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Guo-Dong Li
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Kai-Xue Wang
- School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Jie-Sheng Chen
- School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
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33
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Rao C, Sood A, Subrahmanyam K, Govindaraj A. Graphen, das neue zweidimensionale Nanomaterial. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200901678] [Citation(s) in RCA: 196] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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34
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Rao CNR, Sood AK, Subrahmanyam KS, Govindaraj A. Graphene: the new two-dimensional nanomaterial. Angew Chem Int Ed Engl 2009; 48:7752-77. [PMID: 19784976 DOI: 10.1002/anie.200901678] [Citation(s) in RCA: 1930] [Impact Index Per Article: 128.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Every few years, a new material with unique properties emerges and fascinates the scientific community, typical recent examples being high-temperature superconductors and carbon nanotubes. Graphene is the latest sensation with unusual properties, such as half-integer quantum Hall effect and ballistic electron transport. This two-dimensional material which is the parent of all graphitic carbon forms is strictly expected to comprise a single layer, but there is considerable interest in investigating two-layer and few-layer graphenes as well. Synthesis and characterization of graphenes pose challenges, but there has been considerable progress in the last year or so. Herein, we present the status of graphene research which includes aspects related to synthesis, characterization, structure, and properties.
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Affiliation(s)
- C N R Rao
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P. O., Bangalore 560 064, India.
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35
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Moscardó F, San-Fabián E. On the existence of a spin-polarized state in the n-periacene molecules. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.08.032] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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36
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Boukhvalov DW, Katsnelson MI. Chemical functionalization of graphene. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:344205. [PMID: 21715780 DOI: 10.1088/0953-8984/21/34/344205] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Experimental and theoretical results on chemical functionalization of graphene are reviewed. Using hydrogenated graphene as a model system, general principles of the chemical functionalization are formulated and discussed. It is shown that, as a rule, 100% coverage of graphene by complex functional groups (in contrast with hydrogen and fluorine) is unreachable. A possible destruction of graphene nanoribbons by fluorine is considered. The functionalization of infinite graphene and graphene nanoribbons by oxygen and by hydrofluoric acid is simulated step by step.
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Affiliation(s)
- D W Boukhvalov
- Institute for Molecules and Materials, Radboud University Nijmegen, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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37
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Enoki T, Takai K, Osipov V, Baidakova M, Vul' A. Nanographene and nanodiamond; new members in the nanocarbon family. Chem Asian J 2009; 4:796-804. [PMID: 19378299 DOI: 10.1002/asia.200800485] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Nanographene and nanodiamond are new members of nanocarbons, which consist of nano-sized hexagonal and tetrahedral networks, respectively. The presence of edges and surfaces distinguishes nanographene and nanodiamond, respectively, from other nanocarbons owing to their structure dependent electronic features. Nanographene has an unconventional nonbonding pi-state (edge state) localized around its edge that is dependent on the edge geometry. The edge states, having localized spins, impart a nanographene-based molecular magnetic character. The structure and electronic/magnetic properties of nanodiamond vary depending on how the surface carbon atoms are terminated. Nanodiamond, with a naked surface, is subjected to structural reconstruction at the expense of sigma-dangling bonds. The hydrogenation of the surface is expected to give an electron reservoir function. The incompletely hydrogenated surface is magnetic with surface-induced spins.
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Affiliation(s)
- Toshiaki Enoki
- Department of Chemistry, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
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38
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Rao CNR, Biswas K, Subrahmanyam KS, Govindaraj A. Graphene, the new nanocarbon. ACTA ACUST UNITED AC 2009. [DOI: 10.1039/b815239j] [Citation(s) in RCA: 588] [Impact Index Per Article: 39.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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39
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Jiang J, Lu W, Bernholc J. Edge states and optical transition energies in carbon nanoribbons. PHYSICAL REVIEW LETTERS 2008; 101:246803. [PMID: 19113645 DOI: 10.1103/physrevlett.101.246803] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2008] [Revised: 10/20/2008] [Indexed: 05/27/2023]
Abstract
The edge states and optical transition energies in carbon nanoribbons are investigated with density-functional calculations. While the ground state of zigzag ribbons is spin polarized, defects at the edges destroy spin polarization and lead to a nonmagnetic ground state. Scanning tunneling spectroscopy will thus show different features depending on edge quality. Optical transition energies in nanoribbons Eii are strongly affected by the edges and confinement, which introduce a term inversely proportional to their width. After removing that term, the scaling of Eii is quantitatively similar to that in carbon nanotubes.
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Affiliation(s)
- J Jiang
- Center for High Performance Simulation, North Carolina State University, Raleigh, North Carolina 27695-7518, USA
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40
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Tang C, Yan W, Zheng Y, Li G, Li L. Dirac equation description of the electronic states and magnetic properties of a square graphene quantum dot. NANOTECHNOLOGY 2008; 19:435401. [PMID: 21832693 DOI: 10.1088/0957-4484/19/43/435401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Electronic eigenstates of a square graphene quantum dot (GQD) terminated by both zigzag and armchair edges are derived in the theoretical framework of the Dirac equation. We find that the Dirac equation can determine the eigenenergy spectrum of a GQD with high accuracy even if its size is reduced to a few nanometers. More importantly, from the Dirac equation description we can readily work out the number and energy gap of the conjugate surface states, which are intimately associated with the magnetic properties of the GQD. By using the Hartree-Fock mean field approach, we study the size dependence of the magnetic ordering formation in this square GQD. We find that there exists a critical size of the width between the two zigzag edges to indicate the onset of the stable magnetic ordering. On the other hand, when such a width increases further, the magnetic ground state energy of a charge neutral GQD tends to a saturated value. These results coincide with the previous results obtained from the first-principles calculation. Then, based on the Dirac equation solution about the surface state, we establish a simple two-state model which can quantitatively explain the size dependence of the magnetic ordering in the square GQD.
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Affiliation(s)
- Changlin Tang
- National Laboratory of Superhard Materials, Department of Physics, Jilin University, Changchun 130023, People's Republic of China. State Key Lab of Structural Chemistry, Fujian Institute of Research on the Structure of Matter and Graduate School of Chinese Academy of Sciences, Fuzhou 350002, People's Republic of China
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41
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Bhowmick S, Shenoy VB. Edge state magnetism of single layer graphene nanostructures. J Chem Phys 2008; 128:244717. [DOI: 10.1063/1.2943678] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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42
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Castro EV, Peres NMR, Stauber T, Silva NAP. Low-density ferromagnetism in biased bilayer graphene. PHYSICAL REVIEW LETTERS 2008; 100:186803. [PMID: 18518403 DOI: 10.1103/physrevlett.100.186803] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Indexed: 05/26/2023]
Abstract
We compute the phase diagram of a biased graphene bilayer. The existence of a ferromagnetic phase is discussed with respect to both carrier density and temperature. We find that the ferromagnetic transition is first-order, lowering the value of U relatively to the usual Stoner criterion. We show that in the ferromagnetic phase the two planes have unequal magnetization and that the electronic density is holelike in one plane and electronlike in the other.
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Affiliation(s)
- Eduardo V Castro
- CFP and Departamento de Física, Faculdade de Ciências, Universidade do Porto, P-4169-007 Porto, Portugal
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43
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Enoki T, Takai K. Unconventional electronic and magnetic functions of nanographene-based host–guest systems. Dalton Trans 2008:3773-81. [DOI: 10.1039/b800138n] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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44
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Thomas A, Fischer A, Goettmann F, Antonietti M, Müller JO, Schlögl R, Carlsson JM. Graphitic carbon nitride materials: variation of structure and morphology and their use as metal-free catalysts. ACTA ACUST UNITED AC 2008. [DOI: 10.1039/b800274f] [Citation(s) in RCA: 2551] [Impact Index Per Article: 159.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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45
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Affiliation(s)
- De-en Jiang
- Chemical Sciences Division and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Sheng Dai
- Chemical Sciences Division and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
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46
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Enoki T, Kobayashi Y, Fukui KI. Electronic structures of graphene edges and nanographene. INT REV PHYS CHEM 2007. [DOI: 10.1080/01442350701611991] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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47
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Jiang DE, Sumpter BG, Dai S. First principles study of magnetism in nanographenes. J Chem Phys 2007; 127:124703. [PMID: 17902927 DOI: 10.1063/1.2770722] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Magnetism in nanographenes [also known as polycyclic aromatic hydrocarbons (PAHs)] is studied with first principles density functional calculations. We find that an antiferromagnetic (AFM) phase appears as the PAH reaches a certain size. This AFM phase in PAHs has the same origin as the one in infinitely long zigzag-edged graphene nanoribbons, namely, from the localized electronic state at the zigzag edge. The smallest PAH still having an AFM ground state is identified. With increased length of the zigzag edge, PAHs approach an infinitely long ribbon in terms of (1) the energetic ordering and difference among the AFM, ferromagnetic, and nonmagnetic phases and (2) the average local magnetic moment at the zigzag edges. These PAHs serve as ideal targets for chemical synthesis of nanographenes that possess magnetic properties. Moreover, our calculations support the interpretation that experimentally observed magnetism in activated carbon fibers originates from the zigzag edges of the nanographenes.
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Affiliation(s)
- De-en Jiang
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
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48
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Jiang DE, Sumpter BG, Dai S. Unique chemical reactivity of a graphene nanoribbon's zigzag edge. J Chem Phys 2007; 126:134701. [PMID: 17430050 DOI: 10.1063/1.2715558] [Citation(s) in RCA: 200] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The zigzag edge of a graphene nanoribbon possesses a unique electronic state that is near the Fermi level and localized at the edge carbon atoms. The authors investigate the chemical reactivity of these zigzag edge sites by examining their reaction energetics with common radicals from first principles. A "partial radical" concept for the edge carbon atoms is introduced to characterize their chemical reactivity, and the validity of this concept is verified by comparing the dissociation energies of edge-radical bonds with similar bonds in molecules. In addition, the uniqueness of the zigzag-edged graphene nanoribbon is further demonstrated by comparing it with other forms of sp2 carbons, including a graphene sheet, nanotubes, and an armchair-edged graphene nanoribbon.
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Affiliation(s)
- De-en Jiang
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
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49
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Goettmann F, Fischer A, Antonietti M, Thomas A. Chemical Synthesis of Mesoporous Carbon Nitrides Using Hard Templates and Their Use as a Metal-Free Catalyst for Friedel–Crafts Reaction of Benzene. Angew Chem Int Ed Engl 2006; 45:4467-71. [PMID: 16770823 DOI: 10.1002/anie.200600412] [Citation(s) in RCA: 482] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Frederic Goettmann
- Max-Planck-Institute of Colloids and Interfaces, Department of Colloid Chemistry, Research Campus Golm, 14424 Potsdam, Germany
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50
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Goettmann F, Fischer A, Antonietti M, Thomas A. Chemische Synthese von mesoporösen Kohlenstoffnitriden in harten Templaten und ihre Anwendung als metallfreie Katalysatoren in Friedel-Crafts-Reaktionen. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200600412] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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