DOCSLIB.ORG

Graphite Oxide, Carbon Nanotubes and Their Composite Effect of Irradiation

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Graphite Oxide, Carbon Nanotubes and Their Composite Effect of Irradiation Danubia NanoTech, s.r.o. Research in science and technology Properties of Graphite Oxide, Carbon Nanotubes and their Composite Effect of Irradiation Viera Skákalová 2001-2011 2011- ???? Max Planck Institute for Solid State Research University of Vienna Stuttgart Collaboratations Danubia NanoTech, s.r.o. Research in science and technology Sample preparation, characterization: TEM, modelling: Viliam Vretenár Jannik Meyer Martin Hulman Franz Eder Peter Kotrusz Jani Kotakoski Marcel Meško Max Planck Institute, Stuttgart Hungarian Academy of Sciences: Electronic transport: Ion irradiation: Dong Su Lee Zsolt E. Horvath Hye Jin Park Laszlo P. Biro Different modifications of carbon Danubia NanoTech, s.r.o. Research in nanoscience and nanotechnology • Production of Single Wall Carbon Nanotubes • Research on SWNT • Production of Few-Layer Graphene • Research on Graphene Defects in SWNTs Raman specroscopy - inelastic photon scattering G D* RBM Raman Intensity (a.u.) 0 500 1000 1500 2000 2500 3000 Raman shift (cm-1) D-mode of Raman spectra increases with the Dose of Ar+ ions D-mode 632 nm pristine 6 D-mode 632 nm12 4.0x10 ions/cm2 pristine 2 12 5 5.0x10 4.0x1011 ions/cm 2ions/cm2 1.0x1012 ions/cm12 2 4.0x10 ions/cm2 2.0x1012ions/cm2 4 1 3 D 2 IntensityIntensityIntensityIntensity (a.u.) (a.u.) (a.u.) (a.u.) Intensity (a.u.) 0 1 1200 1300 1400 Wavenumber (cm-1) 0 500 1000 1500 2000 2500 3000 Wavenumber (cm-1) SWNT paper irradiated by 23 MeV C4+ ions ions Greater damage at the REAR side 8 Back side Irradiated side 6 o )/I o 4 -I d (I 2 D‐mode 0 0 5 10 15 20 25 30 Dose (1013 ion/cm2) Skakalova, Kaiser, Detlaff, Arstila, Krashenninikov, Keinonen, Roth: Physica Status Solidi B, 245, (2008) 2280‐2283 C4+‐irradiation of SWNT paper: Electrical conductivity C4+-energy = 23 MeV 400 Quasi-1D metal C4+ energy = 23 MeV 0 300 300 T = 300K 1. 1014 ion/cm2 200 200 3 10 100 100 30 Conductivity (S/cm) Conductivity (S/cm) 0 Variable-range hopping 0 102030 0 100 200 300 2 Temperature (K) Dose (ion/cm ) Electrical conductance of Ar+ irradiated thin SWNT networks ions 1.2 + o Ar energy = 30 keV 0.8 G(Dose)/G 0.4 0.0 0510 Dose (1012 ion/cm2) 1/(1d ) T Variable‐Range Hopping: ()T exp 0 0 T Surface penetration by 30 keV Ar+ ions ions Dose effects of 30 keV Ar+ ions + 8 0.2 Ar energy = 30 keV o 6 ]/G o o 0.1 )/I o -I 4 d (I 0.0 D-mode 2 [G(Dose)-G -0.1 0 0 5 10 15 20 25 0 5 10 15 20 25 12 2 Dose (1012 ion/cm2) Dose (10 ion/cm ) V. Skakalova, A.B. Kaiser, Z. Osvath, G. Vertesy, L.P. Biro, S. Roth, Appl. Phys. A 90, 597–602 (2008) Effect of thermal annealing: Recovering structure of SWNTs Pristine Irradiated Annealed IntensityIntensityIntensity D 1100 1200 1300 1400 Wavenumber (cm-1) Viera Skákalová, Janina Maultzsch, Zoltán Osváth, László P. Biró, and Siegmar Roth, Phys. Stat. Sol. (RRL) 1, No. 4, 138– 140 (2007) Defects in Graphene Hexagonal crystal structure of graphene Two equivalent sub‐lattices A and B TEM study of electron irradiation: 12C vs 13C Direct knock-on damage: Energy = 95 keV, Dose of 1.4 x 109 e/nm2 12C 13C no damage Damage induced by contamination initial after exposure Jannik C. Meyer, et al. , PHYSICAL REVIEW LETTER 108, 196102 (2012) Measured and calculated knock-on displacement cross sections. Monovacancy: dangling bond with a much lower emission threshold. Subsequent sputtering of this atom may double the cross section. The lower boundary of the shaded areas correspond to the calculated cross section. The upper boundary is twice the calculated value (expected for correlated sputtering). Jannik C. Meyer, et al. , PHYSICAL REVIEW LETTER 108, 196102 (2012) Temperature dependences of conductance Ni‐ A few layers catalyst 2 nm Cu-catalyst A monolayers Monocrystal 1 nm Defects formed in presence of ammonia 1 nm 1. pristine CVD‐monolayer 2. N‐doped CVD‐monolayer -5 10 1 10-6 D 2 2D Sheet conductance (S) Sheet conductance (S) 10-7 10 100 Temperature (K) G H. J. Park, V. Skákalová, T. Iwasaki, J. C. Meyer, U. Kaiser and S. Roth, Physica Status Solidi B, 247(2010)2915‐2919 Chemical Oxidation‐Reduction of Graphite Graphite oxide was first prepared by Oxford chemist Benjamin C. Brodie in 1859 Oxidation introduces functional groups: A: Epoxy bridges B: Hydroxyl groups C: Pairwise carboxyl groups Reduction removes functional groups - Restores sp2 orbitals - Leaves many structural defects Microscopic characterization of thermally reduced Graphite Oxide (rGO) SEM of GO flakes (Hummers) STEM of reduced GO Spectroscopic characterization of thermally reduced Graphite Oxide (rGO) Raman spectra GO GO reduced GO reduced GO 1.0 1.0 1.0 1 nm 0.5 0.5 0.5 Intensity (norm. to G-mode) Intensity (norm. to G-mode) Intensity (norm. to 0.0 0.0 G-mode) Intensity (norm. to 0.0 500 1000 1500 2000 2500500 3000 1000 3500 1500 2000 2500500 3000 1000 3500 1500 2000 2500 3000 3500 -1 -1 -1 Wavenumber (cm ) Wavenumber (cm ) Wavenumber (cm ) X‐ray Photo‐electron Spectra Thorough removal of oxide groups Microscopic characterization of thermally reduced Graphite Oxide (rGO) HR TEM: Jannik Meyer, Uni Ulm Electrical conductivity of thermally reduced Graphite Oxide (rGO) In comparison with SWNT and SWNT‐GO composite 200 rGO 180 180 160 140 160 120 100 SWNT Conductivity (S/cm) Conductivity (S/cm) Conductivity (S/cm) 140 SWNT-GO RGOrGO 80 100100 Temperature (K) SWNT‐GO • The electrical conductivity of SWNT‐GO composite higher than that of SWNT • Identical electron transport mechanism (Fluctuation Assisted Tunnelling) in SWNT‐GO composite and SWNT paper • Very high electrical conductivity in rGO film with metallic electron transport Summary SWNT networks: ‐ Ion irradiation damages the structure and lowers electrical conductivity ‐ Thermal annealing removes defects in the SWNT structure Graphene: A structural damage affects severaly electronic transport Graphite oxide: Non conductive and transparent. Electrical and optical properties tunable by reduction of the oxide groups. Reduced graphite oxide: Metallic character of electron transport Composite SWNT‐GO: The same mechanism of electron transport like in SWNT film Composite SWNT‐reduced GO: ??????????????? Under investigation. Aknowledgment The results have been acquired within several years of collaboration between Max Planck Institute in Stuttgart Danubia NanoTech (SME) in Bratislava and University of Vienna Thanks for attention SWNT networks ) 1 S 10 ( Buckypaper 100 10-1 10-2 Net 4 Net 3 -3 Net 2 Sheet Conductance Conductance Sheet 10 Net 1 0 20406080100 Transmittance (%).
Load more

Recommended publications
  • Chemistry with Graphene and Graphene Oxide - Challenges for Synthetic Chemists Siegfried Eigler* and Andreas Hirsch*
    Chemistry with Graphene and Graphene Oxide - Challenges for Synthetic Chemists Siegfried Eigler* and Andreas Hirsch* Dr. Siegfried Eigler*, Prof. Dr. Andreas Hirsch* Department of Chemistry and Pharmacy and Institute of Advanced Materials and Processes (ZMP) Henkestrasse 42, 91054 Erlangen and Dr.-Mack Strasse 81, 90762 Fürth (Germany) Fax: (+49) 911-6507865015 E-mail: [email protected]; [email protected] The chemical production of graphene as well as its controlled wet- chemical modification is a challenge for synthetic chemists and the characterization of reaction products requires sophisticated analytic methods. In this review we first describe the structure of graphene and graphene oxide. We then outline the most important synthetic methods which are used for the production of these carbon based nanomaterials. We summarize the state-of-the-art for their chemical functionalization by non-covalent and covalent approaches. We put special emphasis on the differentiation of the terms graphite, graphene, graphite oxide and graphene oxide. An improved fundamental knowledge about the structure and the chemical properties of graphene and graphene oxide is an important prerequisite for the development of practical applications. 1. Introduction: Graphene and Graphene Oxide – Opportunities and Challenges for Synthetic Chemists Research into graphene and graphene oxide (GO) represents an emerging field of interdisciplinary science spanning a variety of disciplines including chemistry, physics, materials science, device fabrication and
    [Show full text]
  • Reduction Kinetics of Graphene Oxide Determined by Electrical Transport Measurements and Temperature Programmed Desorption
    J. Phys. Chem. C XXXX, xxx, 000 A Reduction Kinetics of Graphene Oxide Determined by Electrical Transport Measurements and Temperature Programmed Desorption Inhwa Jung,† Daniel A. Field,‡ Nicholas J. Clark,‡ Yanwu Zhu,† Dongxing Yang,† Richard D. Piner,† Sasha Stankovich,§ Dmitriy A. Dikin,§ Heike Geisler,| Carl A. Ventrice, Jr.,*,‡ and Rodney S. Ruoff*,† Department of Mechanical Engineering and the Texas Materials Institute, UniVersity of Texas at Austin, Austin, Texas, 78712, Department of Physics, Texas State UniVersity, San Marcos, Texas, 78666, Department of Mechanical Engineering, Northwestern UniVersity, EVanston, Illinois, 60208, and Insitute for EnVironmental and Industrial Science, Texas State UniVersity, San Marcos, Texas, 78666 ReceiVed: May 11, 2009; ReVised Manuscript ReceiVed: August 31, 2009 The thermal stability and reduction kinetics of graphene oxide were studied by measuring the electrical resistivity of single-layer graphene films at various stages of reduction in high vacuum and by performing temperature programmed desorption (TPD) measurements of multilayer films in ultrahigh vacuum. The graphene oxide was exfoliated from the graphite oxide source material by slow-stirring in aqueous solution, which produces single-layer platelets with an average lateral size of ∼10 µm. From the TPD measurements, it was determined that the primary desorption products of the graphene oxide films for temperatures up to 300 °C are H2O, CO2, and CO, with only trace amounts of O2 being detected. Resistivity measurements on individual single-layer graphene oxide platelets resulted in an activation energy of 37 ( 1 kcal/mol. The TPD measurements of multilayer films of graphene oxide platelets give an activation energy of 32 ( 4 kcal/mol. 1.
    [Show full text]
  • Static and Dynamic Behavior of Polymer/Graphite Oxide Nanocomposites Before and After Thermal Reduction
    polymers Article Static and Dynamic Behavior of Polymer/Graphite Oxide Nanocomposites before and after Thermal Reduction Kiriaki Chrissopoulou 1,* , Krystalenia Androulaki 1,2, Massimiliano Labardi 3 and Spiros H. Anastasiadis 1,2 1 Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, N. Plastira 100, 700 13 Heraklion Crete, Greece; [email protected] (K.A.); [email protected] (S.H.A.) 2 Department of Chemistry, University of Crete, P.O. Box 2208, 710 03 Heraklion Crete, Greece 3 CNR-IPCF, c/o Physics Department, University of Pisa, Largo Pontecorvo 3, 56127 Pisa, Italy; [email protected] * Correspondence: [email protected]; Tel.: +30-281-039-1255 Abstract: Nanocomposites of hyperbranched polymers with graphitic materials are investigated with respect to their structure and thermal properties as well as the dynamics of the polymer probing the effect of the different intercalated or exfoliated structure. Three generations of hyperbranched polyester polyols are mixed with graphite oxide (GO) and the favorable interactions between the polymers and the solid surfaces lead to intercalated structure. The thermal transitions of the confined chains are suppressed, whereas their dynamics show similarities and differences with the dynamics of the neat polymers. The three relaxation processes observed for the neat polymers are observed in the nanohybrids as well, but with different temperature dependencies. Thermal reduction of the graphite oxide in the presence of the polymer to produce reduced graphite oxide (rGO) reveals an increase in the reduction temperature, which is accompanied by decreased thermal stability of the polymer. Citation: Chrissopoulou, K.; The de-oxygenation of the graphite oxide leads to the destruction of the intercalated structure and Androulaki, K.; Labardi, M.; to the dispersion of the rGO layers within the polymeric matrix because of the modification of the Anastasiadis, S.H.
    [Show full text]
  • Synthesis of Graphene.Pdf
    Materials Chemistry and Physics 206 (2018) 7e11 Contents lists available at ScienceDirect Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys Synthesis of graphene via ultra-sonic exfoliation of graphite oxide and its electrochemical characterization Hassnain Asgar a, K.M. Deen b, Usman Riaz a, Zia Ur Rahman c, Umair Hussain Shah a, * Waseem Haider a, c, a School of Engineering and Technology, Central Michigan University, Mt. Pleasant, MI 48859, USA b Department of Materials Engineering, University of British Columbia, Vancouver, BC V6T 1Z4, Canada c Science of Advanced Materials, Central Michigan University, Mt. Pleasant, MI 48859, USA highlights A relatively direct synthesis method for production of graphene is presented. IR, Raman and XRD analyses confirmed formation of graphene starting from graphite. XPS and TEM characterization validated the formation of graphene. Electrochemical response of GO and graphene was evaluated in de-aerated 0.5M KOH. Presence of functional groups in GO resulted in improved values of Rct and Ceff,p. abstract A direct method of producing graphene from graphite oxide (GO) via ultra-sonication is presented in this work. The synthesis of graphene was validated through IR, XRD, Raman, and XPS analyses. Moreover, the diffraction pattern obtained from TEM also validated the formation of graphene with char- acteristics (002) plane. The electrochemical behavior of GO and graphene was evaluated by electrochemical impedance spectroscopy and linear sweep voltammetry in 0.5M KOH solution. The relatively larger effective pseudocapacitance and broad current peak exhibited by GO in the LSV plots was related with the dominant adsorption of ‘Hads’ during reduction of water.
    [Show full text]
  • The Preparation of Graphene Oxide and Its Derivatives and Their Application in Bio-Tribological Systems
    Lubricants 2014, 2, 137-161; doi:10.3390/lubricants2030137 OPEN ACCESS lubricants ISSN 2075-4442 www.mdpi.com/journal/lubricants Review The Preparation of Graphene Oxide and Its Derivatives and Their Application in Bio-Tribological Systems Jianchang Li 1,2, Xiangqiong Zeng 1,*, Tianhui Ren 2 and Emile van der Heide 1,3 1 Laboratory for Surface Technology and Tribology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands; E-Mails: [email protected] (J.L.); [email protected] (E.H.) 2 School of Chemistry and Chemical Engineering, Key Laboratory for Thin Film and Microfabrication of the Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240, China; E-Mail: [email protected] 3 Netherlands Organisation for Applied Scientific Research—TNO, P.O. Box 6235, NL-5600 HE Eindhoven, The Netherlands * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +31-53-489-4390. Received: 20 June 2014; in revised form: 15 August 2014 / Accepted: 22 August 2014 / Published: 24 September 2014 Abstract: Graphene oxide (GO) can be readily modified for particular applications due to the existence of abundant oxygen-containing functional groups. Graphene oxide-based materials (GOBMs), which are biocompatible and hydrophilic, have wide potential applications in biomedical engineering and biotechnology. In this review, the preparation and characterization of GO and its derivatives are discussed at first. Subsequently, the biocompatibility and tribological behavior of GOBMs are reviewed. Finally, the applications of GOBMs as lubricants in bio-tribological systems are discussed in detail. Keywords: graphene oxide; graphene oxide-based materials; biocompatibility; bio-tribology 1.
    [Show full text]
  • Studies of Reduced Graphene Oxide and Graphite Oxide in the Aspect of Their Possible Application in Gas Sensors
    sensors Article Studies of Reduced Graphene Oxide and Graphite Oxide in the Aspect of Their Possible Application in Gas Sensors Sabina Drewniak 1,*, Roksana Muzyka 2, Agnieszka Stolarczyk 3, Tadeusz Pustelny 1, Michalina Kotyczka-Mora ´nska 2 and Maciej Setkiewicz 1 Received: 25 November 2015; Accepted: 8 January 2016; Published: 15 January 2016 Academic Editor: Gregory Schneider 1 Department of Optoelectronics, Silesian University of Technology, 2 Akademicka Str., Gliwice 44-100, Poland; [email protected] (T.P.); [email protected] (M.S.) 2 Institute for Chemical Processing of Coal, 1 Zamkowa Str., Zabrze 41-803, Poland; [email protected] (R.M.); [email protected] (M.K.-M.) 3 Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, 9 Strzody Str., Gliwice 44-100, Poland; [email protected] * Correspondence: [email protected]; Tel.: +48-32-237-1263 Abstract: The paper presents the results of investigations on resistance structures based on graphite oxide (GRO) and graphene oxide (rGO). The subject matter of the investigations was thaw the sensitivity of the tested structures was affected by hydrogen, nitrogen dioxide and carbon dioxide. The experiments were performed at a temperature range from 30 ˝C to 150 ˝C in two carrier gases: nitrogen and synthetic air. The measurements were also aimed at characterization of the graphite oxide and graphene oxide. In our measurements we used (among others) techniques such as: Atomic Force Microscopy (AFM); Scanning Electron Microscopy (SEM); Raman Spectroscopy (RS); Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Photoelectron Microscopy (XPS). The data resulting from the characterizations of graphite oxide and graphene oxide have made it possible to interpret the obtained results from the point of view of physicochemical changes occurring in these structures.
    [Show full text]
  • The Role of the Oxidation and Reduction Parameters on the Properties of the Reduced Graphene Oxide
    coatings Article The Role of the Oxidation and Reduction Parameters on the Properties of the Reduced Graphene Oxide Marta Sieradzka * , Czesław Slusarczyk´ , Włodzimierz Binia´sand Ryszard Fryczkowski Faculty of Materials, Civil and Environmental Engineering, University of Bielsko-Biala, 43-309 Bielsko-Biala, Poland; [email protected] (C.S.);´ [email protected] (W.B.); [email protected] (R.F.) * Correspondence: [email protected] Abstract: One of the methods of obtaining reduced graphene oxide (rGO) involves the oxidation of graphite to graphene oxide, which is then exfoliated and reduced. Each of these stages has a decisive influence on the properties of the produced nanoadditive, which determines its subsequent application. The process conditions which are examined during the oxidation stage are related to: The mixing time of the reactants before oxidation, sonication of the reaction mixture, and its composition. During reduction optimization, in turn, the form of the GO sample and the method of its purification, as well as the temperature at which this process took place, are examined. At each stage, the determined structural parameters of the produced materials (GO and rGO) are related to their morphology (SEM—scanning electron microscope), oxidation state (FTIR—Fourier transform infrared spectroscopy, EDS—energy-dispersive spectrometer), structure defect (Raman spectroscopy), as well as the number of layers and crystalline structure (WAXS—wide-angle X-ray scattering). The obtained results show that the shorter mixing time of the reactants determines the formation of more oxygen functional groups. On the basis of the obtained results, the process conditions that enable the production of multilayer, well-exfoliated reduced graphene oxide, with only a slightly defected ´ Citation: Sieradzka, M.; Slusarczyk, structure, are established.
    [Show full text]
  • A Thermally Reduced Graphite Oxide and Carbon Nanotube Composite for Supercapacitor Applications
    New Physics: Sae Mulli, Vol. 68, No. 2, February 2018, pp. 181∼184 http://dx.doi.org/10.3938/NPSM.68.181 A Thermally Reduced Graphite Oxide and Carbon Nanotube Composite for Supercapacitor Applications Gyawali Ghanashyam · Hae Kyung Jeong∗ Department of Physics, Institute of Basic Science, Daegu University, Gyeongsan 38453, Korea (Received 15 December 2017 : revised 8 January 2018 : accepted 14 January 2018) A thermally reduced graphite oxide and carbon nanotube (TRGO-CNT) composite is synthesized for supercapacitor applications by using a simple chemical method. The TRGO-CNT composite shows higher capacitance then the precursors (TRGO and CNT), and its impedance is lower than that of CNT, meaning that TRGO of high surface area connected with a CNT could provide highly efficient surface area and good connection for supercapacitor electrodes. Different weightratios of TRGO to CNT are investigated, and the results show that the composite with more TRGO has better performance in the electrochemical measurements. Based on these findings, the proper TRGO amount is necessary for a high-performance supercapacitor. Neither CNT nor TRGO by itself can give the highest electrochemical performance for the supercapacitor; thus, the synergistic effect of TRGO and CNT is important. PACS numbers: 88.30.rh, 81.05.U-, 81.40.-z Keywords: Carbon nanotube, Graphene oxide, Reduced graphene oxide I. INTRODUCTION has the precious properties such as high thermal con- ductivity (∼5000 Wm−1K−1) and skyscraping electron Supercapacitor is known as a complementary device mobility (200,000 cm2V−1s−1). Moreover, graphene can of other power sources such as batteries and fuel cells, be made from graphite which is cheap and has a large and it can have long life cycles and rapid charging time reserve in nature so that it has become the “rising star” by high power density due to its highly reversible charge for high technology research work.
    [Show full text]
  • Carbon Dioxide Capture with Amine Functionlized Graphene Oxide
    University of Mississippi eGrove Electronic Theses and Dissertations Graduate School 2015 Carbon Dioxide Capture With Amine Functionlized Graphene Oxide Renee Zeleszki University of Mississippi Follow this and additional works at: https://egrove.olemiss.edu/etd Part of the Chemical Engineering Commons Recommended Citation Zeleszki, Renee, "Carbon Dioxide Capture With Amine Functionlized Graphene Oxide" (2015). Electronic Theses and Dissertations. 917. https://egrove.olemiss.edu/etd/917 This Thesis is brought to you for free and open access by the Graduate School at eGrove. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of eGrove. For more information, please contact [email protected]. CARBON DIOXIDE CAPTURE WITH AMINE FUNCTIONLIZED GRAPHENE OXIDE A Thesis Presented in partial fulfilment of requirements For the degree of Master of Science In the Department of Chemical Engineering The University of Mississippi By RENEE RAN WEI ZELESZKI August 2015 Copyright Renee Zeleszki 2015 ALL RIGHTS RESERVED ABSTRACT Amine functionalized graphene oxide was used as sorbent in order to achieve carbon dioxide capture. In this study, micro size graphite flakes was prepared according to Modified Hummers method and “Hummers’ method with additional KMnO4”. Graphene oxide was then functionalized with ethylenediamine (EDA). Different purification methods for graphene oxide were studied as well as different functionalization method times. Graphite oxide and functionalized graphene oxide has been analyzed with Fourier transform infrared spectroscopy (FTIR) for chemical structure. Thermal gravimetric analysis (TGA) was used to test CO2 capture capacity. Functionalized graphene oxide that has been purified with 30 washes via centrifuge with 72 hour amine functionalization method time had greatest CO2 capture potential with 1.38% weight increase.
    [Show full text]
  • Graphite Oxide Template Based Synthesis and Characterization of Metal Oxide Nanosheets by Kyle B. Tom a Dissertation Submitted I
    Graphite Oxide Template Based Synthesis and Characterization of Metal Oxide Nanosheets By Kyle B. Tom A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Engineering – Materials Science and Engineering in the Graduate Division of the University of the California, Berkeley Committee in charge: Professor Jie Yao, Chair Professor Oscar D. Dubόn Professor Vivek Subramanian Summer 2018 Graphite Oxide Template Based Synthesis and Characterization of Metal Oxide Nanosheets Copyright 2018 By Kyle B. Tom Abstract Graphite Oxide Template Based Synthesis and Characterization of Metal Oxide Nanosheets by Kyle B. Tom Doctor of Philosophy in Engineering – Materials Science and Engineering University of California, Berkeley Professor Jie Yao, Chair Two dimensional materials and their composite structures show unique and favorable properties for many different kinds of applications and physical studies. Isolated 2D materials have shown a unique array of physical phenomena, including the room temperature observation of the quantum Hall effect, as well as enhanced physical properties, including large exciton energies and extremely high carrier mobilities. Composites have shown enhanced performance in traditional applications, including enhanced photocatalysis and battery performance, that stems from a synergistic effect between the individual materials in the composite. However, there is a limited number of naturally layered materials, an even smaller subset that is stable in ambient conditions. As such, it is beneficial to find 2D materials with better properties that may originate from other types of crystals. It has been predicted certain types of crystal structures, such as wurtzite, will form a two-dimensional phase similar to αBN below a particular thickness threshold.
    [Show full text]
  • Microwave Enabled Fabrication of Highly Conductive Graphene and Porous Carbon/Metal Hybrids for Sustainable Catalysis and Energy
    MICROWAVE ENABLED FABRICATION OF HIGHLY CONDUCTIVE GRAPHENE AND POROUS CARBON/METAL HYBRIDS FOR SUSTAINABLE CATALYSIS AND ENERGY STORAGE by Keerthi Savaram A Dissertation submitted to the Graduate School-Newark Rutgers, The State University of New Jersey in partial fulfillment of the requirements for the degree of Doctor of Philosophy Graduate Program in Chemistry written under the direction of Professor Huixin He and approved by ________________________ ________________________ ________________________ ________________________ Newark, New Jersey October, 2017 Copyright Page Copyright © 2017 Keerthi Savaram ALL RIGHTS RESERVED Abstract of the dissertation MICROWAVE ENABLED FABRICATION OF HIGHLY CONDUCTIVE GRAPHENE AND POROUS CARBON/METAL HYBRIDS FOR SUSTAINABLE CATALYSIS AND ENERGY STORAGE By Keerthi Savaram Dissertation Director: Prof. Huixin He Carbon is the most abundant material next to oxygen in terms of sustainability. The potential of carbon based materials has been recognized in recent decades by the discovery of fullerene (1996 Nobel prize in chemistry), carbon nanotubes (2008 Kavli prize in nanoscience) and graphene (2010 Nobel prize in physics). The synthesis of carbon materials with well controlled morphologies lead to their exploration in both fundamental research and industrial applications. Graphene also commonly referred to as a wonder material has been under extensive research for more than a decade, due to its excellent electronic, optical, thermal and mechanical properties. However, the realization of these applications for practical purposes require its large scale synthesis. The common method of graphene synthesis involves reduction of graphene oxide. Nevertheless, complete restoration of intact graphene basal plane destroyed by oxidation cannot be achieved, limiting the application of as synthesized graphene in flexible macro electronics, mechanically and electronically reinforced composites etc.
    [Show full text]
  • Electronic Transport in Composites of Graphite Oxide with Carbon Nanotubes
    Electronic Transport in Composites of Graphite Oxide with Carbon Nanotubes Viera Skákalová1,2*, Viliam Vretenár1,3, Ľubomír Kopera5, Peter Kotrusz1, Clemens Mangler2, Marcel Meško1, Jannik C. Meyer2 and Martin Hulman1,4 1Danubia NanoTech s.r.o., Ilkovičova 3, 84104 Bratislava, Slovakia 2University of Vienna, Faculty of Physics, Group Physics of nanostructured materials, Boltzmanngasse 5, 1090 Vienna, Austria 3Institute of Physics, Slovak Academy of Science, Dúbravská cesta 9, 845 11 Bratislava, Slovakia 4International Laser Center, Ilkovičova 3, 84104 Bratislava, Slovakia 5 Institute of Electrical Engineering, Slovak Academy of Science, Dúbravská cesta 9, 845 11 Bratislava, Slovakia Abstract We show that the presence of electrically insulating graphite oxide (GO) within a single wall carbon nanotube (SWCNT) network strongly enhances electrical conductivity, whereas reduced graphite oxide, even though electrically conductive, suppresses electrical conductivity within a composite network with SWCNTs. Measurements of Young´s modulus and of Raman spectra strongly support our interpretation of the “indirect” role of the oxide groups, present in GO within the SWCNT-GO composite, through electronic doping of metallic SWCNTs. *Tel.: +43 664 60277 51328 *E-mail: [email protected] 1. Introduction Electronic transport in low-dimensional graphitic carbon structures is determined firstly by the dimensionality (0, 1 or 2) of the system. The significance of electronic transport for the zero-dimensional carbon form – fullerene - is negligible, as these tend to avoid double bonds in the pentagonal rings, resulting in poor electron delocalisation, whereas carbon nanotubes, with dimensionality “quasi-one”, as well as entirely 2-dimensional graphene, are well appreciated for their electrical conduction with ballistic transport.
    [Show full text]