Graphene Materials

Graphene Materials

Invited Talk Global Graphene Forum 2016 www.vbripress.com/eamc, DOI: 10.5185/eamc2016 Published online by the VBRI Press in 2016

Thin protective composite coatings on base of graphene nanoplatelets and ALD

Väino Sammelselg

1,2**

Jekaterina Kozlova

1

, Jay Mondal

1

, Alda Simões

3

, Andreia Marques

3

, Lauri Aarik

1

,

1

Institute of Physics, University of Tartu, Tartu, 50411, Estonia

2

Institute of Chemistry, University of Tartu, Tartu, 50411, Estonia

3

Institute of Physics, University of Tartu, Tartu, 50411, Portugal

**Corresponding author. Tel: (+372) 7374705; E-mail: vaino.sammelselg@ut.ee

Table of contents

a b c

Thin protective coatings: a) surface and b) cross-section images of rGO/laminate on stainless steel, and c) polarization curves of bare and coated with rGO, laminate, and composite rGO/laminate stainless steel structures

ABSTRACT

A nanometric (thickness

≤ 200 nm) composite hybrid coating consisting of alternating laminate layers of aluminum and titanium oxides deposited by atomic layer deposition (ALD) onto a thin graphene layer of reduced graphene oxide nanoplatelets (rGO; prepared by modified Hummers method) applied on AISI 304 stainless steel, was developed and its electrochemical properties were studied. The rGO by itself has not revealed significant effects in terms of protection, whereas the laminate (6 thin ALD films of alumina and titania, alternately) reinforced the passivity by decreasing the passive current. The best performance was obtained by the complete system, in which the rGO film acts as a primer for the anchoring of the oxide layer, as a barrier for corrosive ions, and as a shield for local electrical fields if these are generated by starting local corrosion, thus, decreases the tendency to metastable pitting. The porosity of the new coating was very low as estimated using electrodynamic data.

In the presentation more examples of graphene coatings will be given and the characteristics of the coatings will be shown in more detail.

Keywords: Graphene nanoplatelets, Stainless steel; Corrosion protection; Amorphous oxides; ALD

Acknowledgements

L. A. and J. K. thank the European Social Funds of Doctoral Studies and J.

Mondal acknowledges the Internationalization Program DoRa for financial support. This work was also supported by the Estonian ME&S by projects

IUT2-24, TK117 and 12164T. The Portuguese FCT is also acknowledged for

PhD grant SFRH/BD/72161/2010 (A. G. M.) and for financial support under contract UID/QUI/00100/2013.

Reference

1.

J. Mondal, A. Marques, L. Aarik, J. Kozlova, A. Simões, V. Sammelselg ,

Corrosion Science, 2016 , doi:10.1016/j.corsci.2016.01.013

.

Copyright © 2016 VBRI Press 1


Nanostructured Hybrid Materials for Lithium-

Sulfur Batteries

Yanglong Hou

*

, Sarish Rehman

Department of Materials Science and Engineering, College of Engineering, Peking University,

Beijing 100871, China

*Corresponding author. Tel/Fax: (+86) 10 62753115; E-mail: hou@pku.edu.cn


Rational Design of Si/SiO

2

@Hierarchical Porous Carbon Spheres for Efficient Li-S Batteries

ABSTRACT

Lithium-sulfur batteries (LSBs) possess low cost, high theoretical capacity (1672 mAh/g) and environmental benignity, however, severe self-discharge, short cyclic lifetime and fast capacity fading during the dynamic cell cycling hamper its wide scale commercialization. Herein, we will present some progress on nanostructured hybrid materials for lithium-sulfur batterries. First, we demonstrate a controlled strategy for synthesizing a new class of silicon/silica crosslink with hierarchical porous carbon spheres (Si/SiO

2

@C) as high efficient sulfur hosts for promoting LSBs. Benefiting from both the large surface area of porous carbon and crosslink network of Si/SiO2, the Si/SiO2@C hybrid not only overcomes the limitations of low sulfur loading but also functions as internal reservoir that adsorbs negatively charged polysulfides via both chemical and physical adsorption. As a result, the hybrid spheres deliver a high capacity of 1215 mAh g-1 at 0.2 C and high cycling stability with ultra-low capacity decay of 0.063 % per cycle for 500 cycles. The present work highlights the dual role of Si/SiO

2

@C-S hybrid spheres in hosting maximum amount of sulfur to achieve more efficient Li-S battery. And then, we propose a unique nanostructure of three dimensional (3D) and interconnected porous carbon nanosheets, synthesized by a simple carbonization of agar, which can be applied as both the effective sulphur host to alleviate the polysulphide anions dissolution in electrolyte during the LSBs cycling, and the advanced conducting support for improving the capacity of electroactive sulphur. The key feature of the interconnected


Invited Talk Global Graphene Forum 2016 porous carbon nanosheets is that they possess many 3D channels with macrovoids and mesopores with high surface area of 1750 m

2

/g, which play an important role in acting as the multilayered physical barrier against polysulphides anions and prevents its dissolution in the electrolyte during charge-discharge process. Most importantly, the present work highlights the vital role of the nanostructured hybrid materials in enhancing the performance of LSBs.

Keywords: Nanostructure; Hybrid; Cathode, Lithium-sulfur Batteries


This work was financially supported by NSFC (51125001,51172005), NSFC-

RGC(51361165201).

Reference

1. S. Rehman, S. Guo, Y. Hou, Advanced Materials, in press, 2016 .

2. N. Mahmood, J. Zhu, S. Rehman, Q. Li, Y. Hou, Nano Energy 11,

755

–

765, 2015 .

3. Q. Li, N. Mahmood, J. Zhu, Y. Hou, S. Sun, Nano Today 9, 668

–

683,

2014 .

4. N. Mahmood, C. Zhang, F. Liu, J. Zhu, Y. Hou, ACS Nano 11,

10307

–

10318, 2013 .

5. C. Zhang, N. Mahmood, H. Yin,; F. Liu, Y. Hou, Advanced

Materials, 25, 4932

–

4937, 2013 .



Terahertz spectroscopy of graphene

Ivan Ivanov 1 , Zoltán Mics

Xinliang Feng

1 , Klaas-Jan Tielrooij

1

, Klaus Müllen

1

, Mischa Bonn

2 , Søren Jensen 1 , Khaled Parvez 1 ,

1

, Dmitry Turchinovich

1**

1

Max Planck Institute for Polymer Research, Mainz, D-55128, Germany

2

ICFO

–

The Institute for Photonic Sciences, Barcelona, 08860, Spain

**Corresponding author. Tel: (+49) 6131379522; Fax: (+49) 6131379360;

E-mail: turchino@mpip-mainz.mpg.de


Ultrafast terahertz linear, nonlinear and photo-conductivity of graphene is well described by a simple thermodynamic model.

ABSTRACT

The linear band structure of graphene ensures large DC carrier mobility, enabling numerous electronic applications of this remarkable material, many of which are expected to operate at very high frequencies and field strength. However, the conduction properties of graphene in this regime are largely different from the DC parameters. In this work we study the high-field AC conductivity of graphene in the terahertz (THz) frequency range via all-optical, contact-free method

–

high-field THz spectroscopy. We show that in graphene the ultrafast electron transport can be described by a simple thermodynamic picture.

Within this picture, the interaction of a strong electromagnetic wave with graphene leads to the heating of graphene electron population. Due to an ultrafast sub-30 fs carrier-carrier scattering in graphene the carrier system equilibrates in a nearinstantaneous fashion, and thus the effect of interaction of the THz field with graphene can be described simply as an increase in its electron heat. For the arguments of particle number conservation, the chemical potential of hotter electron gas in graphene decreases, reducing its intraband conductivity. The electron cooling, in its turn, occurs via a few-picosecond phonons emission.

This competition of heating and cooling of the electronic system of graphene determines the instantaneous conductivity of graphene which nonlinearly depends on the dynamics and the strength of electromagnetic field. In our experiments we studied a p-doped CVD-grown graphene on fused silica substrates. We found a substantial reduction of graphene conductivity with increasing THz frequency and increasing peak electric field [1]. In order to model the observed high-field THz conductivity spectra we quantified the electron heat deposited into the carrier system by the absorption of the THz pulse. By accounting for the energy and particle number conservation we calculated the temperature and the chemical potential of the carriers, in turn directly yielding the frequency dependent conductivity of the thermalized electron gas in graphene. The possibility to reduce the electromagnetic field - carrier interaction to a mere thermodynamic heat exchange significantly simplifies the understanding of ultrafast graphene electronics, yielding highly-accurate description of experimental data. We also studied the THz


Invited Talk Global Graphene Forum 2016 photoconductivity of optically excited graphene [2]. Surprisingly, the same model accounting for the heating of the carriers as a result of the energy transfer from the photo-generated excess electron-hole pairs describes the measured data perfectly well. This in particular allowed us to quantify the distribution of the energy relaxation pathways in photo-excited graphene between electron-phonon and electron-electron channels [2], [3].

Keywords: Carrier transport in graphene; ultrafast phenomena; THz spectroscopy.


The authors acknowledge support from the Max Planck Graduate Center, ERC grants on NANOGRAPH and 2DMATER, DFG Priority Program SPP 1459,

EU Project GENIUS, MOLESOL and EC under Graphene Flagship (No.

CNECT-ICT-604391) and EU Career Integration Grant 334324 (LIGHTER).

Reference

1. Z. Mics, K.-J. Tielrooij, K. Parvez, S. A. Jensen, I. Ivanov, X.

Feng, K. Müllen, M. Bonn, and D. Turchinovich, Nat. Commun., 6,

7655, 2015 .

2. S. A. Jensen, Z. Mics, I. Ivanov, H. S. Varol, D. Turchinovich, F.

H. L. Koppens, M. Bonn, and K. J. Tielrooij, Nano Lett., 14, 5839

–

5845, 2014 .

3. I. Ivanov, M. Bonn, Z. Mics, and D. Turchinovich, EPL -

Europhys. Lett., 111, September, 67001, 2015 .



Designing carbon-based systems into ferromagnetic and topological

Hideo Aoki

**

Department of Physics, University of Tokyo, Hongo, Tokyo 113-0033 Japan

*Corresponding author. E-mail: aoki@phys.s.u-tokyo.ac.jp


Left: Four classes of long-period graphene [1]. Right: Designed metal-organic framework [2].

ABSTRACT

Flat-band ferromagnetism, conceived by Lieb, by Mielke and by Tasaki in the 1980-90's has a unique mechanism in that the magnetism arises from unusual

“

Wannier

”

orbits rather than the mere flatness of the band. If we systematically look for realisation of flat bands in two-dimensional materials, graphene-related systems provide an ideal arena, where Shima and

Aoki[1] have proposed back in the 1990's that some classes of long-period graphene with antidot arrays systematically accommodate flat bands, along with Dirac cones, for a group-theoretical reason. The system, nowadays dubbed carbon nanomesh, is attracting renewed interests. In this talk I shall introduce our most recent proposal, inspired by Shima-Aoki scheme, designed for a new kind of organic nanomesh, i.e., 2D metal-organic frameworks (MOFs). The designed MOF has a virtue that flat bands arise right around the Fermi energy, which is a prerequisite for the flat-band magnetism. A spin-density functional electronic structure calculation confirms that ferromagnetism indeed emerges for the right choice of materials. On top of this, if we consider the spin-orbit interaction arising from metallic atoms, the flat band can even become topological. Thus organic materials are envisaged to open a unique avenue for designing magnetism. The work on the MOF is a Tokyo-MIT collaboration.

Keywords: Carbon nanomesh, flat-band ferromagnetism, metal-organic framework, topological system


I wish to thank Nobuyuki Shima, Masahiko Yamada, Tomohiro Soejima, Naoto

Tsuji, Daisuke Hirai, and Mircea Dinca for collaborations, This work was supported in part by MEXT Grant Nos. 26247064, 25107005, 25610101, and by

ImPACT from JST.

References

1.

N. Shima, H. Aoki, Phys. Rev. Lett.

71, 4389, 1993 ; N. Shima, H.

Aoki, in prep .

2.

M. Yamada, T. Soejima, N. Tsuji, D. Hirai, M. Dinca, H. Aoki, arXiv:1510.00164.


Oral European Advanced Materials Congress 2016 www.vbripress.com/eamc, DOI: 10.5185/eamc2016 Published online by the VBRI Press in 2016

Mechanism of delaminating chemical vapor deposited graphene from its native metal substrate by electrochemical bubbling

Lihui Liu

1

, Xin Liu

2

, Weiling Guo

2

, Chen Xu

2

Chakarov

3

, Per Hyldgaard

1

, Jun Deng

2

, Zhaoyao Zhan

1

, Elsebeth Schröder

1

, August Yurgens

1

, Dinko

, Jie Sun

1, 2**

1

Department of Microtechnology and Nanoscience, Chalmers University of Technology,

Göteborg 41296, Sweden

2

College of Electronic Information and Control Engineering, Beijing University of Technology,

Beijing 100124, China

3

Department of Applied Physics, Chalmers University of Technology, Göteborg 41296, Sweden

**Corresponding author. Tel: (+46)-31-7723117; E-mail: jie.sun@chalmers.se


The mechanism for the efficient/nondestructive graphene electrochemical transfer using gas bubbles is for the first time revealed.

ABSTRACT

In many cases, transfer of the chemical vapor deposited 2D materials from their metallic foil catalysts such as copper [1] and platinum [2] onto an insulating target substrate is the most critical step for their promising fundamental studies and industrial applications. Recently, a highly efficient and non-destructive electrochemical delamination method has been proposed as an alternative method to the conventional etching transfer method, which alleviates the problem of cost and environment pollution because it eliminates the need to etch away the ultrapure metals [3, 4]. However, the seemingly simple mechanism of the bubbling method is never fully understood. Here, the mechanism of the electrochemical bubbling delamination process is for the first time elucidated by studying the effect of the various electrolytes on the delamination rate. A capacitor-based circuit model is proposed and confirmed by the electrochemical impedance spectroscopy results [5]. The values of the corresponding lump elements in the circuit model can be extracted from our measurements. According to this model, the full delamination of the graphene can be viewed as the electric “breakdown” of one of the capacitors formed between the electrolyte and the sample.

A


Oral European Advanced Materials Congress 2016 factor of 27 decrease in the time required for the complete graphene delamination from the platinum cathodes is found when increasing the NaOH ratio in the electrolyte solution (see the figure above). Similar effect has also been observed when delaminating graphene from copper foils. The phenomenon is symmetrically inversed for the anode situation. That is, when connecting the graphene/metal sample to the anode of the electrolytic cell, O

2

instead of H

2

bubbles are used to delaminate the graphene, where a more acidic electrolyte is now beneficial in achieving a high delamination rate. The surface screening effect induced by the nonreactive ions in the vicinity of the electrodes plays a key role in the delamination efficiency (see the figure above). The so-called nonreactive ions refer to, for example, Na

+

in NaOH and NO

3

-

in HNO

3

electrolytic solutions. Although they never take part in the water electrolysis reaction, many of them are attracted to the vicinity of the negative or positive electrodes due to the Coulombic forces, and screen out the H

+

or OH

-

from the back side of the metal foils (open surface). This effect offers the main driving force for the H

2

or O

2

bubbles to squeeze into the graphene-metal interface and separate them. Our results show that if the ionic screening effect is absent, although numerous bubbles are still formed, they are primarily gathered at the backside of the metal foils and can hardly delaminate the graphene from metals at the interface. Although it seems to be not straight forward to reveal the screening effect at a first glance, it is can be well understood using the capacitor-based circuit model we have proposed. Our discovery is generic and can be used as a guideline to describe and design the electrochemical delamination of other 2D materials from their metal catalysts as well, which is very important for the real application of this technology in industry, exploring its full potential in terms of economic and environmental aspects.

Keywords: Electrical mechanism, electrochemical delamination, graphene transfer, chemical vapor deposition


We sincerely thank Stiftelsen Olle Engkvist Byggmästare, Carl Tryggers Stiftelse, Chalmers Area of Advance, Stiftelsen för Strategisk Forskning, and Beijing

Natural Science Foundation (4152003).

References

1.

J. Sun, N. Lindvall, M. T. Cole, K. T. T. Angel, T. Wang, K. B. K. Teo,

D. H. C. Chua, J. Liu, A. Yurgens, IEEE Trans. Nanotechnol.

2012, 11,

255.

2.

J. Sun, Y. Nam, N. Lindvall, M. T. Cole, K. B. K. Teo, Y. W. Park, A.

Yurgens, Appl. Phys. Lett.

2014, 104, 152107.

3.

C. J. L. de la Rosa, J. Sun, N. Lindvall, M. T. Cole, Y. Nam, M. Löffler,

E. Olsson, K. B. K. Teo, A. Yurgens, Appl. Phys. Lett. 2013 , 102,

022101.

4.

Z. Zhan, J. Sun, L. Liu, E. Wang, Y. Cao, N. Lindvall, G. Skoblin, A.

Yurgens, J. Mater. Chem. C 2015, 3, 8634.

5.

L. Liu, X. Liu, Z. Zhan, W. Guo, C. Xu, J. Deng, D. Chakarov, P.

Hyldgaard, E. Schröder, A. Yurgens, J. Sun, Adv. Mater. Interf.

2015, in press.



Spin transport in graphene monolayer antiferromagnetic calculated using the Kubo formalism

Leonardo dos Santos Lima

1

,

1

Centro Federal de Educação Tecnológica de Minas Gerais ,Belo Horizonte, 30510-000 , Brazily

**Corresponding authot. Tel: +5531998996706; E-mail:lslima@des.cefetmg.br


Please m ake a brief schematic diagram as the ‘Table of Contents’. Insert those Graphics and Synopsis here. Please make sure that this can illustrate your work briefly but completely. Below is sample of schematic diagram.

On/off-switchable zipper-like super-thin power bioelectronics.

ABSTRACT

We have used the massless Dirac's quasiparticles together with the Kubo's formula to study the spin transport properties in graphene. We have calculated the spin conductivity and verified the behavior of the Ac and Dc spin conductivities of this system which is a relativistic electron plasma. We results show a ballistic spin transport for all T , T>0 and the behavior of Ac rom an ideal spin conductor at T>0 to spin insulator at T=0 occurring of a suave form.

Keywords: Spin Transport; Graphene; Monolayer.


This work was partially supported by the Brazilian agencies FAPEMIG, CNPq and CEFET-MG.

Reference

A.

H. Castro Neto, F. Guinea, N. M. R. Peres, K. S. Novoselov, A. K. Geim,

Reviews of Modern Physics 81, 109 (2009).

B.

J. Lee, S. Sachdev, Phys. Rev. Letters 114, 226801 (2015).

C.

A. S. T. Pires, L. S. Lima, Phys. Rev. B 79, 064401 (2009)..

D.

L. S. Lima, submitted to Journal (2016),



Lamellar structures from graphene nanoparticles

Kartel Mykola

1**

, Sementsov Yuriy

1

, Dovbeshko Galyna

2

,

Karachevtseva Liudmyla

3

1

O. Chuiko Institute of Surface Chemistry, NAS of Ukraine, Kyiv;

2

Institute of Physics, NAS of Ukraine, Kyiv;

3

V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kyiv

**Corresponding authot. Tel: (+380) 44 4238058; Fax: (+380) 44 4243567;

E-mail: nikar@kartel.kiev.ua


SEM images of graphene structures on the gold surface

(substrate inclined at an angle of 60º to the e-probe). lg (s, Oм -1.

см -1

)

1

2

0

-0,75

-0,2

-0,8

-0,85

-0,4

-0,6

-0,9

-2 -1 0 1 2 3 4 5 lg(f,

Гц)

-0,8

0 20 40 60 80 100 120 140 160 t, o

C

Dependences of real part of graphene conductivity vs frequency and temperature at heating (1) and cooling (2).

ABSTRACT

Expanded graphite (EG) is a nanoscale clusters system comprising cylindrical, conical or slit-like structures of 0.7-20 nm. The domain size of 20 nm was detected by X-rays coherent dispersion in tangent and normal direction [1]. Therefore, the EG is the most attractive precursor for graphene nanoplatelets for industrial production.

Graphene nanoparticles were obtained by repeated intercalation of graphite foil under low concentration of alkaline electrolyte solution (KOH) and the density of electrical current in the range of 6 - 60 mA/cm

2

. The graphite foil served as an electrode [2].

The nanoparticles (NP) were analysed by Raman scattering (RS) methods (the spectrometer Brucker RFS 100/s, the radiation source is an argon laser,



= 514.5 nm), laser correlation spectroscopy (LCS) (spectrometer "ZetaSizer 3" from Malvern

Instrument (UK) with correlation 7032 and a helium-neon laser LH-111 has a capaci ty of 25 mW, wavelength λ = 633 nm) and scanning electron microscopy (SEM) (JEOL SL6060LA, Japan). Software in the corresponding CONTIN mode ("modal field" approximation) allows determining the distribution of particle volumes (in the case of constant density for the masses) and the number of particles of a certain size, in the approximation of spherical particles.

The LCS analysis of the particles showed two fractions of particles in solution. The large particles (13 µm) were sedimentated for some time. The second group of the particles in the 20-450 nm range was more stable in solution.

RS studies showed that characteristic peaks of the samples are similar to those of few graphene layers and graphite crystals. The spectra are characterized by intense G and 2D bands at ~1582 and ~2713 cm

-1

, respectively. Also listed are the less intense D and D+D" of the defect bands at ~1355 and ~2451 cm

-1

. Lower intensity of 2D band in our case may be due to the presence of some disordered structure of graphene, as evidenced by the appearance in the spectrum of the defected D-band. It is known that the emergence and growth of intensity of D-band is accompanied by the relevant drop in intensity of the 2D band. However, it was also shown that for multilayer graphene, in which there is no AB

–

ordering of the layers (AB

–

stacking order), and instead, they are oriented chaotically relative to each other, is also logged quite intense, symmetric 2D band.


Oral European Advanced Materials Congress 2016

The solution after electrochemical treatment of graphite foil and separation from large particles was deposited on gold film substrate, dried and then analysed by SEM. It clearly shows the lamellar structure of the particles. There are particles looking like

“hedgehogs” formed from thin graphene platelets with one end fixed at th e same point. These "hedgehogs" are similar to the honeycomb surface of EG with significantly smaller cell size and thinner walls. Obtained results could be used in biomedical applications.

Conductivity of graphene materials occurs due to the electronic component. The increase in conductivity of the dispersed graphene system after heating indicates a decrease in the contact resistance between the particles, i.e. change chemical state of the surface.

Keywords: Graphene; lamellar structure; synthesis; properties.


This work was supported by the Project of the Swedish Research Council

(VR) under contract #348-2014-4250.

Reference

1.

G.І. Dovbeshko, V.S. Kopan, S.L. Revo et al,

Metal Physics and

Latest Technology, 27(3), 1001

–

1010, 2005 .

2.

Yu.

І

. Sementsov, M.T. Kartel, Chem. Industry of Ukraine , 3, 56

–

63,

2015 .


Oral Global Graphene Forum 2016 www.vbripress.com/eamc, DOI: 10.5185/eamc2016 Published online by the VBRI Press in 2016

Synthesis of Scalabale Graphene for corrosion protection applications

Karanveer S. Aneja, A. S. Khanna

**

Department of Metallurgical and Materials Engineering and Materials Science, Indian

Institute of Technology Bombay, Mumbai 400076, India

**khanna@iitb.ac.in. Tel: (+91) 2225767891; E-mail: khanna@iitb.ac.in


ABSTRACT

Graphene appears to be a wonder material of the present decade. Although there is limited potential for its use as a structural material itself, when combined with other materials, it imparts special properties such as electrical conductivity, electronic mobility, mechanical strength, optical properties as well as protection against corrosion [1].

One of the biggest bottlenecks of its widespread usage is its availability in large volumes. Hence any research which focuses on industrial scalable production is the need of the hour. Keeping this in mind, two ecofriendly approaches have been developed to produce graphene, using high crystalline graphite.

High shear liquid exfoliation process has been reported earlier [2] but makes use of an organic solvent, NMP.

This process has been modified to replace NMP with water and also to improve the overall efficiency.

Alternatively, a novel high pressure liquid exfoliation route has been developed using airless spray equipment. Preliminary studies have shown graphene yield of 15-20% from a starting material of graphite.

Copyright © 2016 VBRI Press

1

Oral Global Graphene Forum 2016

Detailed characterisation of the produced graphene such as the number of layers, its purity, electrical conductivity has been carried out and its use as a pre-treatment primer as a replacement for Cr (VI) based coatings has been established [1]. Simultaneously its use in modifying the properties of organic coatings has also been evaluated. Further, in order to establish the mechanism by which graphene protects against corrosion various studies such as water/gas permeability, electrochemical impedance spectroscopy (EIS), scanning electrochemical microscopy (SECM/SVET) has been conducted.

Keywords: Graphene, High scale production, Corrosion, Protection mechanism

Reference

1.

2.

Aneja, K.S., et al., Graphene based anticorrosive coatings for Cr(vi) replacement. Nanoscale, 2015.

7(42): p. 17879-17888.

Paton, K.R., et al., Scalable production of large quantities of defect-free few-layer graphene by shear exfoliation in liquids. Nat Mater, 2014. 13(6): p. 624-630.


1


‘Green’ reduced graphene oxide for electronic and magnetic materials

Darminto

1*

, Yoyok Cahyono

1

, Wayan Gede Suharta

2**

1

Department of Physics, Faculty of Mathematics and Sciences, Institut Teknologi Sepuluh

2

Nopember, Kampus ITS Sukolilo, Surabaya, 60111, Indonesia.

Department of Physics, Faculty of Mathematics and Sciences, Udayana University, Jimbaran,

Bali, Indonesia.

**Corresponding author. Tel: (+62) 813304896985; Fax: (+62) 315943351; E-mail: darminto@physics.its.ac.id.


A step-bystep process to produce ‘green’ reduced graphene oxide products and their characterizations

.

ABSTRACT

Graphene is one of the compounds of carbon (C) most recently known, and is multipurpose particularly in its application as electronic and even magnetic materials. Graphene composed of 1-3 layers of hexagonal carbon bonds are now commonly made of graphite base material; as a source of carbon derived from minerals beside coal. In this study, graphene and especially its derivatives, such as graphene oxide (GO) and reduced graphene oxide (rGO), will by trial be synthesized from the coconut shells as a ‘green’ (renewable) carbon source. This waste of coconut has primarily been develope d into rGO that results in products in the form powders, solutions and films. In a sense of applications, further development focuses on the rGO as electronic, magnetic and electromagnetic materials.

Keywords: reduced graphene oxide; coconut shell; electronic; magnetic

Reference (Not more than 5, please follow the below reference style if any).

1.

F.A. Prasetya, M. Nasrullah, A.Y. Nugraheni, Darminto , Materials

Science Forum, 287 , 190-193, 2015.

2.

F.M. Wachid, A.Y. Perkasa, F.A. Prasetya, N. Rosyidah, and Darminto,

AIP Conference Proceedings,1586, 202-205, 2014.



More than Moore Applications from Graphene

Anderson Smith 1** , Sam Vaziri 1 Max Lemme 2 Mikael Östling 1

1

KTH Royal Institute of Technology, 164 40, Sweden

2

University of Siegen, Siegen, 57076, Germany

**Corresponding authot. Tel: (+46) 739811221; Fax: (+46) 87904300; E-mail: andsmi@kth.se


More than Moore applications based on graphene devices

ABSTRACT

As devices continue to shrink following Moore’s law, there is an increasing demand for integration of different functionaliti es within devices on the same chip. This scaling in not only the size of the devices but also an improvement in their diversification of their functionality is known as more than Moore. Diversification drives technology toward higher value systems of integrated devices. More than Moore comprises a wide range of fields from various sensors, to radio frequency (RF) for high speed communication. Novel device concepts based on graphene and other 2D-crystals have attracted a lot of attention due to their potential high performance [1]. Graphene has shown to have remarkable electrical and mechanical properties making it well suited for a wide range of potential applications. In this work, high-sensitivity pressure sensors have been developed based on graphene. These devices utilize the piezo resistive effect as the sensing mechanism [2]. The pressure sensors function by trapping air beneath a suspended membrane over a cavity. Changes in the environment will then create a pressure difference between the environment and the air trapped in the membrane – thereby straining it. This strain introduces a measureable resistance change. Further, graphene can be used as a resistive humidity sensor with fast response and recovery times [3]. In this work, we investigate device performance and design characteristics of graphene based pressure and gas sensors. In doing so we will assess further design improvements and integration potential of these devices into CMOS process flows.

This work further explores vertical graphene-base transistors (GBTs) which are a novel device concept promising very high frequency operation. The GBT combines the hot electron transistor (HET) with the unique combination of high conductivity and thinness of graphene. A graphene-base layer is isolated from an emitter and collector by thin dielectrics. The emitter-base insulator (BCI) is a tunnel barrier modulated through the emitter-base voltage to facilitate the electron tunnelling from the emitter to the base. Due to it extreme thinness, graphene does not scatter electrons passing perpendicular to its planar surface and thereby acts as an ideal base material. At the base, the hot-electrons with energies higher than the base-collector barrier can enter the conduction band of the base-collector insulator and finally at the collector. We have, previously, demonstrated the first experimental proof of concept GBT [4] and further improved upon device design and performance [5]. We further investigate



GBT’s different characteristics. These investigations reveal the possible quasi balli stic carrier transport even in a non-optimized

GBT. Even in presence of the opposed electric field, when the BCI barrier height is lower than the energies of the hot-electrons, some of these electrons can reach the collector. This is a strong evidence for quasi-ballistic transport. Furthermore, the functionality of the fabricated GBTs with optimized barriers will be discussed. The optimized GBT utilizes a bilayer tunnel barrier stack as the EBI and the graphene/semiconductor Schottky junction as the base-collector barrier. The incorporation of these diverse graphene based devices can lead to increased functionality in system on chip (SoC) architectures.

Keywords: Graphene, Pressure Sensor, Gas Sensor, Transistor, Moore


Support from the European Commission through two ERC Starting Grants

(InteGraDe, 307311 & M&M’s, 277879), the Swedish Research Council

(E0616001 and D0575901, iGRAPHENE), as well as the German Research

Foundation (DFG, LE 2440/1-1) is gratefully acknowledged.


1.

M. C. Lemme, L.-J. Li, T. Palacios, F. Schwierz , MRS Bulletin, 39(8),

711-718, 2014 .

2.

A. D. Smith, F. Niklaus, A. Paussa, S. Vaziri, A. C Fischer, M. Sterner,

F. Forsberg, A. Delin, D. Esseni, P. Palestri, M. Östling, M. C. Lemme ,

Nanoletters, 13(7), 3237-3242, 2013 .

3.

A. D. Smith, K. Elgammal, F. Niklaus, A. Delin, A. C. Fischer, S.

Vaziri, F. Forsberg, M. Råsander, H. Hugosson, L. Bergqvist, S.

Schröder, S. Kataria, M. Östling, M. C. Lemme , Nanoscale, 7(45),

19099-19109, 2015 .

4.

S. Vaziri, G. Lupina, C. Henkel, A. D. Smith, M. Östling, J. Dabrowski,

G. Lippert, W. Mehr, and M. C. Lemme , Nanoletters, 13(4), 1435-

1439, 2013 .

5.

S. Vaziri, M. Belete, E. D. Litta, A. D. Smith, G. Lupina, M. C. Lemme,

M. Östling , Nanoscale, 7(30), 13096-13104, 2015 .



Novel Inorganic Synthesis Layered Mesoporous

Silica Nanosheets

Khaled Mohammad Saoud

Nasr Bensalah khatat

2

2

1**

, Rola Mohammad Al Soubaihi

, Shaheen Abdulhafez Al Muhtaseb

2

1

, Shaukat Saeed

1

,

, Ahmed Mohamed Reda El

1

Virginia Commonwealth University in Qatar, Doha, Qatar

2

Qatar University, Doha, Qatar

**Corresponding author. Tel: (+974) 66037810; Fax: (+974) 4402 1489; E-mail: s2kmsaou@vcu.edu


Please make a brief schematic diagram as the ‘Table of Contents’. Insert those Graphics and Synopsis here. Please make sure that this can illustrate your work briefly but completely. Below is sample of schematic diagram.

Schematic diagram of Layered SiO

2

Nanosheets Synthesis.

ABSTRACT

Silicon nanostructures gained a lot of interest in the recent years as a promising material for many environmental and industrial applications such as catalyst support, separation medium, electronics, photonics, and an anode for the next generation highperformance Li-ion batteries due to their unique properties and its high theoretical capacity. Although these materials show significantly improved performance, soft synthesis of such materials is challenging. In this work, a multilayer structure mesoporous silica nanosheets with high surface area and uniform pore size are synthesized for the first time by inorganic wet chemistry using Cetyltrimethyl Ammonium Bromide (CTAB) as template. The morphology and porosity of these nanosheets can be controlled by the concentration of the surfactant, heat treatment, reaction time. The effect of the surfactant concentration, pH, and heat treatment on the structure, and morphology of the materials were investigated using various characterization techniques such as scanning electron microscope (SEM), Transmission Electron microscope (TEM), X-Ray diffraction (XRD), Energy

Dispersed X-Ray (EDX), BET surface Area measurement, and pore structure measurements. Our results indicate that the synthesized sheets are stoichiometric highly porous SiO

2

with a surface area over 800 m

2

/g with high aspect ratio (1-2 nm thick and over 150 nm long). And finally, we found that the CTAB concentration, reaction time, and heat treatment play a significant role in the synthesis.

Keywords: SiO

2

Nanosheets; Layered Silica; inorganic synthesis of SiO

2

nanosheets


This publication was made possible by an NPRP award NPRP 7 - 567 - 2 - 216

] from the Qatar National Research Fund (a member of The Qatar Foundation).


1.

D. Barrera et al./Adsorption Science & Technology Vol. 29 No. 10 2011

2.

Kaiqi Xu, Liubin Ben, Hong Li and Xuejie Huang*, Nano Research

Nano Research, DOI 10.1007/s12274DOI 10.1007/s12274,

MarchMarchMarch March 26, 201, 201, 201, 201, 2015



Charge transport in Weyl 2D materials

Halina Grushevskaya

1

, George Krylov

1**

, Dmitry Serow

2

1

Physics Department, Belarusian State University, 4 Nezaleznasti ave., Minsk, 220030, Belarus

2

Peter the Great St. Petersburg Polytecnic University, St.Petersburg, 195251, Russia

**Corresponding author. Tel: (+375) 296624495; Fax: (+375) 2095445; E-mail: krylov@bsu.by


Model & Theory



Band structure & Weyl nodes



Stability analysis and "Moire patterns"



Charge Transport r

Interaction of valley currents with pseudospins, stability of Weyl 2D materials band structure and charge carrier transport.

ABSTRACT

Materials with strong spin-orbit interaction are promising for the development of a new generation of electronic devices - nanoelectronic devices with control of their electrical characteristics by a magnetic field. In this work we use the quasirelativistic model of Dirac 2D material in tight-binding approximation with accounting of



-electron orbitals. We demonstrate that the model admits a Weyl type of charge carriers described by chiral Weyl spinors. Our goal is to demonstrate that the stability of band structure of Weyl 2D materials is stipulated by interaction of valley currents with pseudospins of chiral Weyl charge carriers and perform simulation of charge transport in these materials. With this goal a theoretical approach to the band theory of two-dimensional (2D) semimetals within the self-consistent Dirac--Hartree--Fock field approximation has been developed. It reveals partially breaking symmetry of Dirac cone affected by quasi-relativistic exchange interactions for 2D crystals with hexagonal symmetry. Fermi velocity becomes an operator within this approach, elementary excitations are threeparticle fermionic excitons described by Majorana rather than Dirac equation. Such features of the band structure of 2D semimetals as appearance of 4 pairs of Weyl-like nodes and Dirac cone replicas is shown to be naturally explained with the developed formalism. Numerical simulation of the band structure has been performed for the proposed 2D-model of C and Pb atoms monolayers, taking into account only corrections up to 4th order in q respectively. Hole and electron valence and conduction bands have been calculated. Since, according to band structure simulations, the Dirac cone replica split into oppositely directed cones, the monolayers of atoms C and Pb are 2D Dirac materials, in which pairs of Weyl massless fermions can be excited. Since Weyl fermions in a pair have equal in absolute value but opposite in sign values of pseudo-helicity

(topological charge), then due to the law of conservation of topological charge Weyl fermions can decay only in pairs, rather than individually. Therefore, in contrast to the Dirac electrons and holes Weyl fermions are long-lived quasiparticles.

Keywords: 2D materials; Dirac--Hartree--Fock self-consistent field approximation; Weyl-like nodes; Fermi velocity operator.


This work has been support in part by the Research grant within the Basic

Research Program of the Republic of Belarus.


1.

H.V. Grushevskaya, G. Krylov, J. of Modern Phys ., 5, 984-994, 2014 .

2.

H.V. Grushevskaya, G. Krylov, J. Nonlin. Phenom. in Complex Sys . 18,

81 - 98, 2015



Graphene-based nanocomposite anode materials for lithium ion battery

Chenyang Zha,

1,2,3

Kung,

4

Dafang He,

1,2

and Ningzhong Bao

1,2**

Fengjuan Bai,

2

Lixian Li,

1

Liming Shen,

1

Harold H.

1

State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University,

Nanjing, Jiangsu 210009, P. R. China

2

Jiangnan Graphene Research Institute, Changzhou, Jiangsu 213149, P. R. China

3 Ångstr̈m Advanced Battery Centre (ÅABC), Department of Chemistry

-

Ångstr̈m Laboratory,

Uppsala University, Box 538, SE-75121, Uppsala, Sweden.

4

Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA

**Corresponding author. Tel: (+86) 519-81085958; Fax: (+86) 519-81085951; E-mail: nzhbao@njtech.edu.cn


Synthesis and assembly of ordered graphene-based nanostructured composites with enhanced electrochemical properties for high-performance lithium ion battery application

Schematic illustration of microstructural designs of nanocomposite anode materials for lithium ion battery

ABSTRACT

Graphene has attracted intensive interests due to its outstanding mechanical, electrical, thermal, and optical properties and theoretically high surface area of ~2600 m

2

/g. The incorporation of graphene sheets in the electrode materials can facilitate both electron transport and Li

+ diffusion in anchored host materials, thus enhancing electrochemical lithium storage. We have reported various simple solution-based self-assembly methods to fabricate various graphene-based nanocomposite anode materials. The active components with the nanocomposites are Si, TiO

2

, and Fe

3

O

4

in forms of well-dispersed nanoparticles or nanoparticle assemblies.

1-3

The relationship between the unique structural features and the electrochemical performance of these nanocomposites has been investigated. As evidenced by the electrochemical test results, both the particle aggregation and the volume expansion of active nanomaterials within these graphene-based hybrid nanostructures have been effectively suppress.

Moreover, the graphene sheets can improve the electrical conductivity of the nanocomposites. Therefore, the graphene-based nanocomposites exhibit much better performance in terms of rate capability, cycling performance, and stability as anode materials during the charge-discharge process.

Keywords: graphene; anode materials; nanostructure, lithium ion battery


This research was supported by the Natural Science Foundation of China (No.

51425202, No. 51202110) and the Project Funded by the Priority Academic

Program Development of Jiangsu Higher Education Institutions (PAPD).

Reference .

1.

D. He, F. Bai, L. Li, L. Shen a, H. H. Kung, N. Bao, Electrochimica

Acta , 169, 409

–

415, 2015.

2.

C. Zha, D. He, J. Zou, L. Shen, X. Zhang, Y. Wang, H. H. Kung, N.

Bao, J. Mater. Chem. A , 2, 16931

–

16938, 2014.

3.

D. He, L. Li,.F. Bai,.L. C. Zha, Shen,.H. H. Kung, N. Bao, Chemistry - A

European Journal , DOI: 10.1002/chem.201504429, 2016



Knitted Textiles of Dry-jet Wet-spun Graphene

Oxide Fi-bres

Shayan Seyedin

1

, Andrew I. Minett

2

, Joselito M. Razal

1**

1

Institute for Frontier Materials, Deakin University, Geelong, VIC 3220, Australia

2

Department of Chemical and Biomolecular Engineering, The University of Sydney, Sydney,

NSW 2000, Australia

**Corresponding authot. Tel: (+61) 352479337; E-mail: joselito.razal@deakin.edu.au


Dry-jet wet-spinning an effective approach to fabricate knittable graphene oxide fibres.

ABSTRACT

The synthesis of graphene oxide (GO) with large sheets and liquid crystalline (LC) properties has enabled the exciting development of multi-functional GO fibres.

1,2

GO fibers have demonstrated great potential in various applications e.g. energy storage, sensing, and actuation. Further advancement in this area requires the integration of the fibers into textile structures.

However, the GO fibers produced by conventional wet-spinning method did not show sufficient textile processability. GO fibers with suitable mechanical properties need to be produced to meet the requirements of textile processing such as knitting. While, there have been improvements in stiffness and strength of the GO fibers, enhancement of other properties such as stretchability and toughness, which are also necessary to achieve knittability, have been overlooked. We report for the first time the production of highly flexible and tough GO fibers that can be easily knitted using textile machinery. This advancement was achieved by using a highly customized dry-jet wet-spinning technique which consisted of an air gap between a needle and the coagulating solvent placed in a rotary bath configuration. The implementation of this method enabled the drawing of the GO dispersion at several stages during fiber fabrication i.e. in the air gap (jet-drawing) and in the coagulating bath (gel-drawing). Further, detailed study and optimization of the critical fiber spinning parameters such as coagulation composition, GO concentration, and internal needle diameter were carried out which resulted in GO fibers with outstanding mechanical properties (Young’s modulus of ~7.9

GPa, tensile strength of ~135.8 MPa, elongation at break of ~5.9 %, and toughness of ~5.7 MJ m

-3

). These flexible and tough GO fibers were successfully knitted into various textile structures (single- and double-ply with single nylon yarn) using a conventional circular weft knitting machine.

3

The knitted textiles of GO fibers provide novel platforms for the next generation of functional fabrics for a broad range of applications such as wearable energy storage devices.



Keywords: graphene oxide, dry-jet wet-spinning, fibres, knitting, textiles


This work is funded by the Australian Research Council Future Fellowship (FT

130100380). The authors thank the Institute for Frontier Materials at Deakin

University for financial support, and the Materials Node of Australian National

Fabrication Facility (ANFF) and technical staff at the University of Wollongong for the provision of fiber spinning and knitting facilities.

Reference

1.

R. Jalili, S. H. Aboutalebi, D. Esrafilzadeh, R. L. Shepherd, J. Chen,

S. Aminorroaya-Yamini, K. Konstantinov, A. I. Minett, J. M. Razal,

G. G. Wallace , Advanced Functional Materials, 23(43), 5345

–

5354, 2013 .

2.

S. H. Aboutalebi, R. Jalili, D. Esrafilzadeh, M. Salari, Z. Gholamvand,

S. Aminorroaya Yamini, K. Konstantinov, R. L. Shepherd, J. Chen,

S. E. Moulton, P. C. Innis, A. I. Minett, J. M. Razal, G. G. Wallace,

ACS Nano, 8(3), 2456

–

2466, 2014 .

3.

S. Seyedin, M. S. Romano, A. I. Minett, J. M. Razal, Scientific

Reports, 5, 14946, 2015 .


Oral International Conference on Smart Energy Technologies www.vbripress.com/eamc, DOI: 10.5185/eamc2016 Published online by the VBRI Press in 2016

The 2D graphene-like MoS

2

-based regenerable materials for Hg

0

capture and recovery

Haitao Zhao

1

, Xueliang Mu

1

Yao

2

and Tao Wu

1,2**

, Billy Fanady

2

, Siyu Rong

2

, Chengyi Pan

2

, Zesheng

1

Ningbo New Materials Institute, The University of Nottingham, Ningbo 315042, PR China

2

Department of Chemical and Environmental Engineering, The University of Nottingham,

Ningbo 315042, PR China

**Corresponding authot. Tel: +86 (0) 574 8818 0269; Fax: (+86)(0) 574 8818 0125;

E-mail: tao.wu@nottingham.edu.cn


Schematic summary of Hg

0

capture and recovery over the 2D graphene-like MoS

2

-based regenerable adsorbent

ABSTRACT

There have been increasing concerns on the emission of mercury to the atmosphere due to its potent detrimental impacts on biological system and human being’s health. The l argest anthropogenic source of mercury emission is associated with coalutilization, which is expected to be the first key industrial sector to be addressed under Minamata Convention on Mercury.

Therefore, novel materials for the highly efficient and cost-effectively control of mercury emission are urgently needed. In this research, the graphene-like MoS

2

nanosheet containing materials were prepared using a combination of incipient wetness impregnation (IWI) and sulphur-chemical vapour reaction (S-CVR) meth ods over a commercial γ

-Al

2

O

3

support[1, 2]. The 2D

TMD defect-rich MoS

2

ultrathin nanosheet with Brønsted acid sites in the prepared adsorbent was predicted and characterised by the combination of FactSage™ phase d iagram simulation, XPS, HRTEM, XRD, In situ DRIFTS and NH

3

-TPD characterization techniques. Furthermore, the MoS

2

sample were evaluated by the combination of Hg

0

-TPSR dynamic transient analysis and steady-state analysis. The results showed MoS

2

containing materials had excellent performance on Hg

0

capture. The long-time evaluation with kinetic analysis was further carried out. It was demonstrated that the graphene-like defect-rich MoS

2

nanosheets with Brønsted acid sites provided dense active sites for Hg

0

capture as HgS with significant capacity of 18.95 mg/g predicted using the Elovich model. In addition, the potential of recovering Hg

0

as a resource during the regeneration of spent samples was carried out. The results suggested that Hg

0

capture materials regenerated at 200°C showed very similar Hg

0

capacity while those


Oral International Conference on Smart Energy Technologies regenerated at higher temperatures, such as 250°C and 300°C, resulted in a deteriorated capacity in Hg

0

capture. During this process, mercury released from the materials was in its elemental state and could be collected as a saleable resource. It can therefore be concluded that the 2D graphene-like MoS

2

nanosheets containing materials are promising in the Hg

0

capture and recovery and worth.

Keywords: 2D Graphene-like materials, defect-rich MoS

2

nanosheets; Hg

0

capture; Hg

0

recovery.


Following funding bodies are acknowledged for partially sponsored this piece research: Ningbo Bureau of Science and Technology (Innovation Team Scheme,

2012B82011, and Major Research Scheme, 2012B10042), and Department of Science and Technology Zhejiang (Provincial Innovation Team on SOx and NOx

Removal Technologies, 2011R50017).

Reference .

1.

Haitao Zhao, Gang Yang, Xiang Gao, Cheng Heng Pang, Samuel W. Kingman, and Tao Wu*, Environmental Science & Technology, 50(2),1056-1064. 2016.

2.

Haitao Zhao, Xiang Luo, Jun He, Chuang Peng, and Tao Wu*, Fuel, 147(0), 67-75, 2015.


Poster European Advanced Materials Congress 2016 www.vbripress.com/eamc, DOI: 10.5185/eamc2016 Published online by the VBRI Press in 2016

Solution synthesis of novel molybdenum disulfide dendritic structures via self-assembly and their electrical properties

Seoung-Ki Lee

1

, Jae-Bok Lee

2

, Jyoti Singh

2

, Kuldeep Rana

2

, Jong-Hyun Ahn

2

*

1

Soft Innovative Materials Research Center, Institute of Advanced Composite Materials,

2

Korea Institute of Science and Technology, Joellabuk-do 565-905, Republic of Korea

School of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749, Korea

ABSTRACT

In this study, the structure tunable growth of molybdenum disulfide (MoS

2

) is suggested by combines of self-assembly process and thermal decomposition of single source precursor, (NH

4

)

2

MoS

4 by simple dip coating method. The novel approach provide good control of the microstructure of the synthesized MoS

2

such as thickness, shape, and inter wire spacing by controlling evaporation speed of solution on various substrate. Structural characterizations of the microstructures were carried out by Raman spectroscopy, X-ray diffraction, and X-Ray photoelectron spectroscopy. Morphology of the synthesized material was studied using scanning electron microscopy and atomic force microscopy. As a practical application, transparent and flexible MoS

2

field effect transistor was fabricated using transparent graphene electrode. Electrical measurements indicate excellent performance, with a field effect mobility of 45 cm

2

/Vs, sub threshold voltage of 194 mV/dec and on/off ratios > 10

4

. In addition, these devices revealed stable performance at bending configuration, an important feature essential for flexible electronic systems.



3D nickel nitride@nitrogen doped graphene core-shell hybrid for flexible asymmetric supercapacitors

Jayaraman Balamurugan

1

, Tran Duy Thanh

1

, Nam Hoon Kim

1*

,

Joong Hee Lee

1,2*

1

Advanced Materials Institute of BIN Technology (BK21 plus Global) & Dept. of BIN

Convergence Technology, Chonbuk National University, Jeonju, Jeonbuk 561-756, Republic of Korea

2

Carbon Composite Research Centre, Department of Polymer & Nanoscience and

Technology, Chonbuk National University Jeonju, Jeonbuk 561-756, Republic of Korea

*Corresponding authot. Tel: (+82) 832702342; Fax: (+82) 832702341; E-mail: jhl@jbnu.ac.kr and nhk@jbnu.ac.kr


Cyanamide &

Nickel acetate

Pyrolysis

Fabrication

Graphene oxide Nickel nitride@NG ASCs

Fabrication of the hierarchical 3D nickel nitride@NG core-shell hybrid and its application as an electrode material in supercapacitors .

ABSTRACT

A new type of hierarchical 3D nickel nitride@nitrogen doped graphene (3D nickel nitride@NG) core-shell hybrid was successfully synthesized and employed as an electrode material for flexible asymmetric supercapacitors (ASCs). The 3D coreshell hybrid architecture provides efficient charge transfer and prevents the agglomeration and restacking of the NG sheets, which helps better access to the electrode material for the electrolyte ions. The nickel nitride nanoparticles encapsulated within the NG sheets offer a brilliant energy storage characteristics, which result in an ultra-high specific capacitance of 2,089 F g



1

at 1 A g



1 and excellent rate capability with an extraordinary capacitance of 1,448 F g



1

at 100 A g



1

(97.8% capacitance retention after

20,000 cycles). The ASCs fabricated using the 3D nickel nitride@NG core-shell hybrid as the positive electrode and as-prepared

NG as the negative electrode demonstrates exceptional electrochemical performance for practical energy storage devices. The assembled ASCs deliver an excellent energy density (~ 98.96 Wh kg



1

), an ultra-high power density (~ 16870 W kg



1

at 65.08

Wh kg



1

), and outstanding cycleability (~10,000 times). However, they present excellent cycling performance at multirate currents and large currents after 10000 of cycles. The high performance metal nitride core-shell based hybrid nanostructured

ASCs have significant potential applications in electrical vehicles and portable electronics.

Keywords: Asymmetric supercapacitors; three-dimensional nanostructure; core-shell hybrid; metal nitride nanoparticles


This study was supported by the Basic Research Laboratory Program

(2014R1A4A1008140) through the Ministry of Science, ICT

& Future Planning. This work was also supported by the Basic

Science Research Program through the National Research Foundation

(NRF) funded by the Ministry of Education of Korea

(2014R1A1A2056213).


European Advanced Materials Congress 2016 Poster www.vbripress.com/eamc, DOI: 10.5185/eamc2016 Published online by the VBRI Press in 2016

Preparation of rGO/Co

3

M.Selvakumar

**

O

4

composite with high volumetric capacitance in supercapacitors

Department of Chemistry, MIT, Manipal, Karnataka 576104, India

**Corresponding author. Tel: (080) 2924412; Fax: (080) 2571071;

E-mail: selva.kumar@manipal.edu, chemselva78@gmail.com


The preparation process of high surface area reduced graphene oxide/Co

3

O

4

composite

ABSTRACT

The significance of energy devices like supercapacitors, which provide a short load cycle for applications in memory back-up systems, electric vehicles, displays and energy capture from solar cells, has gained the attention many researchers in recent decades. In recent years, numerous novel materials, such as carbon nanotubes, mesoporous carbon and activated carbon used in supercapacitors. Among these materials, graphene nanosheets have shown great potential as appealing candidates for electrode materials in supercapacitors due to their good electrical conductivity, excellent mechanical property and large surface area. In general carbon materials with high surface area (SA) have a low density, which leads to a low volumetric energy density.

Volumetric energy density is extremely important in practical applications because portable appliances require energy storage devices with a small volume and big devices like electric vehicles. It remains challenging to develop a graphene-based material with the high volumetric capacitance and high gravimetric capacitance. Herein, we report a novel method to prepare reduced graphene oxide with a high apparent density. Scheme 1 shows the process of preparation of rGO/Co

3

O

4

composite. Graphene oxide (GO) was prepared by the oxidation of graphite, and then dispersed in deionized water under ultrasonication, Co(NO

3

)

2 was added into the GO solution with stirring. Then NH was heated at 350 o

4

HCO

3

was added into the mixture to form a precipitate Co (OH) (CO

GO composite. The precipitate was centrifuged, washed with deionized water, and then dried at 80 o

3

)-

C. The as-obtained precipitate

C in air for 4 h to obtain rGO-Co

3

O

4

composites. The composites were immersed in HCl and washed with deionized water to obtain high density rGO/Co

3

O

4

composites. The prepared composite is characterized by by X-ray diffraction

(XRD), X-ray photoelectron spectroscopy (XPS), Tunnelling Electron Microscopy (TEM) and Scanning electron microscopy

(SEM). The composite electrochemical characteristics is addressed by different electrolytes (KOH, Na

2

SO

4

and H

2

SO

4

-H

3

PO

4

) and its concentration. Electrochemical experiments showed that the as-prepared sample showed a high specific capacitance of

173 F/g, high energy density of 3.5 W h kg

-1

, high power density of 1.9 kW kg

-1

, in KOH electrolyte. Galvanostatic chargedischarge studies show good performance and stability. In summary, high density rGO/Co

3

O

4

was successfully prepared using a precipitation assisted method. Considering the high density, as well as the excellent electrochemical performances rGO/Co

3

O

4

is a promising candidate for further application in electrochemical power sources.

Keywords: High volumetric capacitance; Galvanostatic charge-discharge; Supercapacitor.


Dr. M. Selvakumar acknowledge the Manipal University funding for presenting the paper in European Advanced Materials and also acknowledge him post graduate students for doing this work.


Poster

References

European Advanced Materials Congress 2016

1.

Y. Li, D. Zhao., ChemComm., 51, 5598-5601, 2015

2.

X. Cao, Z. Yin, H. Zhang, Energy Environmental Science., 7, 1850-1865,

2014.

3.

E. Frackowiak and F. Beguin., Carbon., 39, 937-950, 2001

4.

Y. N. Sudhakar, M. Selvakumar, D. Krishna Bhat, S. Senthilkumar, RSC

Advances., 6, 60039-60051, 2014.


Poster European Advanced Materials Congress 2016 www.vbripress.com/eamc, DOI: 10.5185/eamc.2016

Published online by the VBRI Press in 2016

Hydrogen adsorption geometries on magnesiumdecorated planar ThMoB

4

-type graphene allotrope : A first-principles study

Irem O. Alp

1*

, Sezgin Aydin

1

, Yasemin O. Ciftci

1

1

Department of Physics, Sciences Faculty, Gazi University, Ankara, 06500, Turkey

*Corresponding author Tel: (+90) 312-202 1267; Fax: (+90) 312-212 2279;

E-mail: iremoner@gazi.edu.tr


Atomic arrangements of 10H

2

molecules adsorbed on Mg-decorated ThMoB

4

-type graphene allotrope before (left) and after

(right) geometry optimization.

ABSTRACT

Hydrogen adsorption and storage using layered- or solid-state materials have been attracted a considerable attention, and this area is one of the principal challenges in realizing the hydrogen economy [1]. For economic applications, ideal hydrogen storage materials should have high volumetric and gravimetric densities (DOE

2015 target is 9%), and the binding energy of hydrogen molecules should be in the range of 0.2-0.6 eV/H

2

. In this study, we predict that magnesium decorated planar ThMoB

4

-type graphene allotrope [2] -consisting of pentagons C

5

and heptagons C

7

- can serve as an alternative hydrogen storage medium. The favourite adsorption location for Mg-atom is determined on the layer and afterwards, the possible conﬁ gurations on a single side of Mg-decorated ThMoB

4

-type graphene allotrope layer are studied for 1-10H

2

molecules, and the structural and electronic properties of these structures are investigated. All calculations have been performed by using first-principles calculations based on density functional theory within the local density approximation

(LDA) as implemented in DMol

3

code [3].

Keywords: DMol; ThMoB

4

-type; graphene allotrope; hydrogen storage.

References

1.

Y. Liu, L. Ren, Y. He, H.- P. Cheng, J. Phys.: Condens. Matter, 22, 445301, 2010 .

2.

A.N. Enyashin and A.L. Ivanovskii , Phys. Status Solidi B, 248(8), 1879-1883, 2011 .

3.

B. Delley, J. Chem. Phys.

, 92, 508, 1990 .



Nanostructured carbon materials for hydrogen energetics

Peteris Lesnicenoks

1,2**

, Liga Grinberga

1

, Laimonis Jekabsons

1

,

Gatis Taurins

3

, Janis Kleperis

1

Astrida Berzina

2

,

1

Institute of Solid State Physics, University of Latvia, Riga, LV 1063, Latvia

2

Riga Technical University, Faculty of Materials Science and Applied Chemistry, Institute of

3

Technical Physics, Riga, LV 1048, Latvia

”

Keramserviss

” LTD, Adazi

, LV 2164, Latvia

**Corresponding author. Tel: (+371) 29100445; Fax: (+371) 67132778; E-mail: peteris.lesnicenoks@rtu.lv


Non-reduced GSS (left) and reduced GSS (right) with visible pores (interlayer spaces) for hydrogen storage.

ABSTRACT

Hydrogen storage is one of the main problems, to push forward wide hydrogen usage in transport technology an energetics.

Composites involving nanostructured carbon species could help to find solution for hydrogen storage problem because of their promising surface/volume relation. Not only catalysis and gas sensing on graphene basis should be considered, but also metal decorated graphene structures for use in hydrogen storage should be an active field for research and development. Mainly heat conductivity and large surface area of graphene-like materials can endorse research for hydrogen storage in low pressures and close to RT conditions - increasing possibility for RT-range devices in hydrogen energetics. For increased hydrogen storage investigations, we propose Rare-earth metal intercalated graphene structures, acquired during synthesis of graphene sheets.

Intercalation, or decoration of graphene surfaces and edges have shown possibility to stabilise defects [ 1, 2 ] in Graphene sheets.

Graphene defects have shown to be sensitive against hydrogen gas [ 3 ] and might as well prove themselves stable enough to achieve low pressure hydrogen storage. As well as a simple method is proposed for synthesis of graphene sheet stacks (GSS).

Hydrogen sorption experiment is performed in Sievert’s type device –

combined with mass spectrometer RGA-100. SEM and

RAMAN investigations are realised on intercalated and additional metal free GSS. Texture of such materials often includes pores (interlayer spaces) with sizes under 2 nm. The most efficient materials which meet the requirements for specific pore sizes are currently obtained with thermochemical methods. In the recent decade nanoporous carbon structures have been researched as one of the most suitable materials for hydrogen storage. Little acquired in this field is synthesis of carbon nanomaterials from industrial graphite waste. Our research for stabilisation of electrolyte solution and increased production amounts for dried

– hydrogen accepting samples continues.

Keywords: Hydrogen storage, nanostructures, graphene, intercalation.

Acknowledgements RTU FMSAC TFI, National research program IMIS

2

and

LCP Project no. 666 for financial support.


Poster

References

European Advanced Materials Congress 2016

1.

B. Xu, X.L. Lei, G. Liu, M.S. Wu, C.Y. Ouyang, International Journal of

Hydrogen Energy, 39 17104

–

17111 2014 .

DOI:10.1016/j.ijhydene.2014.07.182

2.

H.J. Hwang, Y. Kwon, H. Lee, Journal of Physical Chemistry C. 116

20220

–

20224 2012 .

DOI:10.1021/jp306222v

3.

N. Ismail, M. Madian, M.S. El-Shall, Journal of Industrial and

Engineering Chemistry 30, 328

–

335 2015 .

DOI:10.1016/j.jiec.2015.06.002



Development of label-free Graphene based biosensor for detection of bacteria

Ashish Pandey

**

, Anjum Qureshi, Javed H. Niazi

Sabanci University Nanotechnology Research and Application Center, Orta Mah. 34956

Istanbul, Turkey

**Corresponding authot. Tel: (+90) 5071266095; Fax: (+90) 2164839885,

E-mail: ashish@sabanciuniv.edu


Fabrication of gold interdigitated microelectrodes capacitor on graphene coated substrate

ABSTRACT

Bacterial detection methods in clinical diagnostics, food and water treatment are essential for estimating health and safety related risks. Use of biosensors facilitates rapid and accurate detection as compared to other conventional methods like flow cytometry, biochemical assays, plating and culturing, microscopy and luminescence spectroscopy which usually require 1-2days to obtain results. Numerous graphene based biosensors have been fabricated with excellent performance in recent years due to outstanding properties of graphene like high electrical conductivity, high carrier mobility and carrier density. However, processing of graphene based biosensors has always proved to be challenging due to critical nature of graphene. In this work we report fabrication of label-free graphene based biosensor for rapid detection of live bacterial cells. Silicon wafer (100) was used as a substrate for fabrication of graphene biosensor. The (3-aminopropyl)triethoxysilane (APTES) functionalized silicon substrate was spin coated with Graphene Oxide Nano-Platelets (GONPs). A series of capacitors consisting of gold interdigitated microelectrodes were then fabricated on the Graphene Oxide (GO) coated silicon surface using photolithography. The presence of uniformly distributed GONPs between the interdigitated electrodes was confirmed by optical and scanning electron microscopy. RAMAN spectroscopy was also used to study the structural changes induced in graphene oxide during the fabrication process. The impedance/capacitance responses were measured on the sensor surface by non-Faradaic electrochemical impedance spectroscopy (nFIES). The capacitive response across the gold interdigitated microelectrodes of capacitors was measured within the frequency range of 10 Hz to 110 Mhz. Results showed that the fabricated sensor had a sensitive bacterial detection range upto the concentration of 100 CFU/mL. The developed graphene based sensor thus offers sensitive, rapid and easy method for bacterial detection even at lower concentrations. As the graphene sheet can be chemically modified and functionalized with several functional groups, it creates further scope to develop graphene based sensor towards higher sensitivity and explicitly for remote environment.

Keywords: Graphene; biosensor; bacterial detection.


This research work was supported through TUBITAK project grant number

114E101


Poster Global Graphene Forum 2016 www.vbripress.com/eamc, DOI: 10.5185/eamc2016 Published online by the VBRI Press in 2016

Flexible cefalexin-immobilized graphene oxide film for antibaterial and drug delivery

Xun Xu, Zhoucheng Wang

**

College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China

**Corresponding authot. Tel: (+86) 18059217473; Fax: (+46) 5912180738;

E-mail: zcwag@xmu.edu.cn


Schematic illustration of the synthetic procedure of the GO-CE film

ABSTRACT

Graphene, a unique carbon material comprises two-dimensional one-atom-thick carbon atoms hexagonally arranged into a 2D structure [1-2]. It has become one of the most attractive function materials in some areas because of its brilliant mechanical and electrical properties. Graphene oxide (GO), an important derivative of graphene, has inherited some unique properties from graphene. Additionally, it contains plentiful kinds of functional groups, such as hydroxyl, carboxyl, epoxide and carbonyl groups on its surfaces. Due to the functionalized surfaces, water-solubility and high specific surface area, GO and its derivatives have been researched as potential biological materials in recent years. It has been proved that GO is an effective absorbent material for several kinds of drugs [3]. These drug mol ecules strongly deposited onto GO surface via interaction, π

-

π bonding and cation

-

π bonding [4]. Hence, GO is a potential material to establish a novel and efficient drug delivery system. So far, researchers have developed a large amount of drug delivery systems based on GO and its derivatives [5]. In some researches, some functional polymer is grafted onto the GO sheet to improve its properties, such as solubility, biocompatibility and interfacial interactivity for specific drug. Several forms of GO-based drug delivery systems have been explored to fit different situations, such as GOpolymer hybird pills and membranes, hydrogels, and water soluble particles. In this work, we successfully produced and characterized a flexible and free-standing antibacterial film based on the cefalexin-grafted GO nanosheets. The film was synthesized by covalently attaching cefalexin onto graphene oxide sheets and then made by filtration of the colloidal suspension.

ATR-FTIR spectra suggest that cefalexin molecules have grafted onto the GO surface and the amide bond is formed. SEM and optical images show that the graphene oxide-cefalexin (GO-CE) film possesses the unique 2D layer-by-layer structure and it could form channels for drug release when immersed in water. The drug loading and release tests certify that the GO-CE film is a promising drug delivery membrane with high load capacity (0.621 mg mg

-1

) and long-acting release properties (72 h), and can


Poster Global Graphene Forum 2016 effectively inhibit the growth of E. coli and S. aureus bacteria while showing minimal cytotoxicity for a long time. The cellular culture results of the HeLa Cells indicate that the GO-CE film exhibits excellent biocompatibility. Given the simple and easy synthesis method of the freestanding and flexible film with superior drug release and antibacterial effects, we expect this new carbon nanomaterial to be used as an efficient, economical antibacterial and drug loading membrane for environmental and medical applications.

Keywords: graphene oxide; chemical synthesis; thin films; antibacterial.


The authors would like to thank the National Natural Science Foundation of

China (51372212).

References

1.

C. Rao, A. K. Sood, K. S. Subrahmanyam, A. Govindaraj, Angew.

Chem., Int. Ed.

, 48, 7752-7777, 2009 .

2.

Y. Zhu, S. Murali, W. Cai, X. Li, J.W. Suk, J.R. Potts, R.S. Ruoff, Adv.

Mater.

, 22, 3906-3924, 2010 .

3.

H. Chen, B. Gao, H. Li, J. Hazard. Mater ., 282, 201-207, 2015 .

4.

X. Qi, P. Gunawan, R. Xu, M.W. Chang, Chem. Eng. Sci ., 84, 552-556,

2012 .

5.

J. Liu, L. Cui, D. Losic, Acta Biomate r., 9, 9243-9257, 2013 .


Poster Global Graphene Forum 2016 www.vbripress.com/eamc, DOI: 10.5185/ggf.2016


Tunable Negative Diffrential Resistance (NDR) in graphene superlattice

Seyed Mahdi Sattari Esfahlan

1

, Javad Fouladi Oskui

1

and Saeid Shojaei

1**

1,2

Photonics Department, Research Institute for Applied Physics and Astronomy (RIAPA),

University of Tabriz, 51665-163 Tabriz, Iran

** Saeid Shojaei. Tel: (+98) 41-33392995; Fax: (+98) 41-33347050;

E-mail: s_shojaei@tabrizu.ac.ir

, shojaei.sh@gmail.com

.


Band diagram (left) and I-V curves of grapheme based superlattice (right).

ABSTRACT

Here, we report negative differential resistance (NDR) in graphene based superlattice. We investigate the role of numbers of periods, the width of barrier and well

‚

the potential barrier height (created by top gate) in graphene superlattice. We observed that for narrow barriers and wide wells‚ the parameter of PVR (peak to valley ratio) is enhanced.

With increasing number of periods‚ interference effects appear and indicates

NDR mechanism. For higher barriers‚

NDR mechanism become weak which results in lower PVR. Our results provide the way to tune the PVR that is important key parameter in Graphene superlattice resonant tunnelling diodes, RTDs.

Keywords: Graphene superlattices; Negative Differential Resistance, RTDs.

Reference

1.

A. Raoux, M. Polini, R. Asgari, A.R. Hamilton, R. Fazio, A.H. MacDonald,

Phys. Rev. B 81 (2010) 073407.

2.

G. M. Maksimova, E. S. Azarova, A. V. Telezhnikov, and V. Burdov ,

Pys.Rev. B 86, 205422 (2012).

3.

Jonas R. F. Lima.

J. Appl. Phys. 117, 084303 (2015)



Excellent microwave absorption in Graphene

/polymer sandwiches

P. Kuzhir

1

, K. Batrakov

Tommi Kaplas

1

, S. Maksimenko

4

, Yuri Svirko

1

, A. Paddubskaya

4

, Philippe Lambin

5

2

, G.Valusis

2

, Rumiana Kotsilkova

3

,

1

Research Institute for Nuclear Problems, Belarusian State University, Belarus

2

Center of Physical Science and technology, Vilnius, Lithuania

3

Open Laboratory on Experimental Micro and Nano Mechanics,

Institute of Mechanics, Bulgarian Academy of Sciences, Bulgaria

4

Institute of Photonics, University of Eastern Finland, Finland

5

Physics Department, University of Namur, Belgium

ABSTRACT

The concentration of large part of incident wave intensity in extremely small volume could be critical for plenty of applications, including sending, detecting, energy storage. Electromagnetic shielding and absorption properties of thin conductive ﬁlms, nanocarbon

-based composites, graphene monolayers and multilayers, and other graphene-based metamaterials have been actively investigated in recent years [1-5]. Recently, we demonstrated that graphene/polymer sandwiches can provide an efficient far-field shielding against microwave radiations [4] allowing one to achieve up to 50% absorption of the incident radiation, depending on the number of graphene sheets and doping level. Fresnel equations predict that an ultrathin free standing conductive film, thousands times thinner than skin depth, is capable to absorb up to 50% of incident electromagnetic radiations. In the microwave range, the same holds true for a free standing graphene sheet. We demonstrate theoretically and prove experimentally that microwave absorptance of graphene can be enhanced considerably by depositing graphene on a dielectric substrate. On the experimental side, we obtain 80% absorptance at 30GHz. Theory predicts that higher absorptance can be achieved with a suitable choice of the dielectric permittivity and the thickness of the substrate. Absorption can also be maximized by choosing the optimum incidence angle for s-polarized waves in free space or by working in the vicinity of the cut-off frequency of the transverse electric mode in waveguide configuration. The polarization sensitivity of the transmittance and reflectance of graphene layers can be used to tune the polarization state of the transmitted and reflected radiations. The possibility to tune electromagnetic response of graphene/polymer sandwiches via mechanical strength and deformations is also addressed in this communication.


The work was carried out within the framework of the FP7- FET Flagship

604391 Graphene. AP acknowledges FP7 project FP7-316633 POCAONTAS.

References

1.

Y. Bludov, N. Peres, and M. Vasilevskiy, J. Opt. 15 , 114004.1

(2013), dOI:10.1088/2040-8978/15/11/114004.

2.

A. Andryieuski and A. Lavrinenko, Opt. Express 21 , 9144 (2013),

DOI:10.1364/OE.21.009144.

3.

L. Falkovsky, J. Phys.: Conf. Series 129 , 012004.1 (2008),

DOI:10.1088/1742-6596/129/1/012004.

4.

K. Batrakov, P. Kuzhir, S. Maksimenko, A. Paddubskaya, S.

Voronovich, Ph. Lambin, T. Kaplas, and Yu. Svirko, Sci. Rep. 4 ,

7191 (2014), DOI:10.1038/srep07191.

5.

K. Batrakov, P. Kuzhir, S. Maksimenko, A. Paddubskaya, S.

Voronovich, T. Kaplas, and Yu. Svirko, APL 103 , 073117 (2013),

DOI:10.1063/1.4818680.



Transparent and Conductive Graphene

Electrodes for UVC LEDs

Chang-Tai Hsiao

1

, Yi-Luen Ma

1

, Hao-Yu Chen

1

, Shu-Fen Hu

1**

, Ru-Shi Liu

2**

1

Department of Physics, National Taiwan Normal University, Taipei 116, Taiwan

2

Department of Chemistry, National Taiwan University, Taipei 106, Taiwan

**Corresponding authors. Tel: (+886) 277346088; Fax: (+886) 229326408;

E-mails: sfhu.hu@gmail.com

; rsliu@ntnu.edu.tw

;


The mechanism of introducing interlayers on the graphene/p-GaN ohmic contact formation.

ABSTRACT

Indium tin oxide (ITO) and fluorine tin oxide (FTO) have been widely used. However, both of them have limited transparency in the ultraviolet region (< 20%). Therefore, finding new material substituted ITO as transparent conductive electrodes is very important for deep ultraviolet (UV) light emitting diode (LED). Graphene is a two-dimensional carbon material which consists of hexagonal array of carbon atoms, and offers exceptional characteristics such as high transparency in UV light, low sheet resistance, suppleness, etc. In this reports we show two kinds of buffer layer which are NiO and ITO nano particles to decrease the Schottky barrier between our Chemical Vapor Deposition (CVD) graphene and p-GaN of UVC LED (300 ~ 200 nm). Ohmic contact formation was realized when interlayer is introduced between the graphene and p-GaN measured by CTLM. The obtained films exhibit a high conductivity of 620 ~ 870



/

฀

and a transparency of more than 77% at 280 nm. The increase of the light output power is attributed to high UV transmittance of graphene, effective current spreading and injection, and texturing effect by ITO nanodots and NiO thin film.

Keywords: Graphene; transparent conductive electrodes; Ohmic contact; light-emitting diodes.


The authors are grateful for the finanicial supports of the Ministry of Science, technology of Taiwan (Contract Nos. MOST 103-2112-M-003-009-MY3 and

MOST 104-2113-M-002-012-MY3), Academia Sinica (Contract No. AS-103-

TP-A06) and National Taiwan University (104R7563-3).

References

1.

L. Wang, W. Liu, Y. Zhang, Z. H. Zhang, S. T. Tan, X. Yi. G. Wang,

X. Sun, H. Zhu, H. V. Demir , Nano Energy, 12, 419-436, 2015 .

2.

S. Chandramohan, J. H. Kang, B. D. Ryu, J. H. Yang, S. Kim, H. Him,

J. B. Park, T. Y. Kim, B. J. Cho, E. K. Sun, C. H. Hong, ACS Appl.

Mater. Interfaces ,

5, 958−964

, 2015.

3.

T. H. Seo, K. J. Lee, A. H. Park, C. H. Hong, E. K. Suh, S. J. Chae, Y.

H. Lee, T. V. Cuong, V. H. Pham, J. S. Chung, E. J. Kim, S. R. Jeon,

Optics Express, 19(23), 23112, 2011.




Catalytic Condensation of Naphtalene: Quantum

Chemical Studies

M.V. Pozharov

1

, O.A. Shinkarenko

1

, A.S. Kolesnikova

2

, R.A. Safonov

2

,

A.S. Chumakov

1,2

, A.J.K. Al-Alwani

1,3

, A.V. Kazak

4

,

N.V. Usol’tseva 4

,

E.G. Glukhovskoy

1,2

*

1

National Research Saratov State University, Saratov, 410012, Russia

2

Education and Research Institute of Nanostructures and Biosystems, Saratov, 410012, Russia

3

Babylon University, Al Hillah, 51001, Iraq

4

Ivanovo State University, Ivanovo, 153025, Russia

Please insert photograph of the presenting author.

*Corresponding author. Tel: (+7 8452) 210750; Fax: (+7 8452) 511527; E-mail: glukhovskoy@gmail.com


Scheme of the catalytic condensation of two naphthalene molecules into perylene

ABSTRACT

Graphene and graphene-related substances have become a subject of many contemporary studies due to their wide range of physical and chemical properties that turn them into very interesting potential nanomaterials that can be further applied in various areas, most importantly

–

medicine

1

, photoelectronics and material science

2

. However, one of the common problems related to aforementioned compounds is providing a cheap and reliable method of synthesis for them. Among such methods, one should note catalytic condensation of aromatic polycyclic hydrocarbons such as naphthalene. This type of reactions has been studied since the beginning of the 20 th

century but quantum chemical computations of such processes have not been performed yet. The first study on the subject used AlCl

3

as a catalyst for naphthalene condensation to perylene. However, other transition metals as well as their salts and complexes can be potentially used as catalysts, which can be confirmed a priori by using the quantum chemical modeling of the path of the reaction. Therefore, the aim of this study is to examine the effect of various catalysts (Pt,

Pd, Ni, PdCl

4

and AlCl

3

) on the path of reaction of naphthalene condensation into perylene (as seen in the Table of Contents) in order to choose the most promising catalyst for future synthesis using quantum chemical methods. The path of reaction for


Poster Global Graphene Forum 2016 naphthalene condensation and potential structures of intermediate complexes with catalysts has been calculated using semiempirical (PM7) and DFT (B3LYP/CRENBL) approaches. Semi-empirical calculations were performed using MOPAC2016 software

3

. DFT calculations were performed using Firefly QC package

4

. The calculated heats of formation (PM7) or free Gibbs energies of formation (B3LYP) were used to calculate the heat (free Gibbs energy) of the aforementioned naphthalene condensation. According to calculation results, Ni and Pd appear to be the most effective catalysts for the studied process as they have the lowest calculated free Gibbs energy of reaction values.

Keywords: graphene synthesis; quantum chemical calculation; naphthalene.


The research is supported by grant of the Russian Science Foundation (project no. 14-12-00275) and the National Research Saratov State University.

References

1.

S. Mahanta, S. Paul Colloids and Surfaces B: Biointerfaces . 134, 178-

187 (2015)

2.

Y. Cao, G. Li, X. Li Chemical Engineering Journal . 292, 207-223

(2016)

3.

MOPAC2016, James J. P. Stewart, Stewart Computational Chemistry,

Colorado Springs, CO, USA, http://OpenMOPAC.net

4.

Alex A. Granovsky, Firefly version 8, http://classic.chem.msu.su/gran/firefly/index.html




Natural graphene in liquid crystal for lubricant composition

N

.V. Usol’tseva 1

, A.V. Kazak

1

, A.I. Smirnova

1

, N.N. Rozhkova

2

,

E.F. Sheka

3

, A.S. Kolesnikova

4

, M.V. Pozharov

4

, E.G. Glukhovskoy

4

*

1

Ivanovo State University, Ivanovo, 153025, Russia

2

Institute of Geology Karelian Research Center RAS, Petrozavodsk, 185910, Russia

3 Peoples’ Friendship University of Russia,

Moscow, 117198, Russia

4

National Research Saratov State University, Saratov, 410012 Russia

Please insert photograph of the presenting author.

*Corresponding author. Tel: (+7 8452) 210750; Fax: (+7 8452) 511527; E-mail: glukhovskoy@gmail.com


ABSTRACT

Developing new processes to obtain few-layer graphene flakes from graphite for the scalable synthesis and industrial application is still a challenge. The known technologies are based on wet chemistry of graphene oxide (GO) and reduced graphene oxide

(rGO) production. The size of the flakes and surface properties, namely concentration of oxygen-containing groups are poorly reproducable [1]. Therefore the presence of graphenes in a natural material provides good production opportunities. Shungite carbon (ShC) is a natural carbon allotrope with a multi-level fractal structure produced by consecutive aggregation of ~1 nm rGO fragments. Turbostratic stacks of ~1.5 nm thick and ~2.5 nm wide and the globular composition of the stacks, ~6 nm in average linear size, are responsible for the secondary and tertiary levels of the structure. Aggregates of globules, measuring tens of nanometres, complete the structure. The first justification of the concept is related to the study of photoluminescence of ShC aqueous and organic dispersions that exhibits properties similar to those of synthetic graphene quantum dots of the rGO origin

[2]. The second was obtained in the course of the neutron scattering study. Being porous due to its fractal structure, ShC provides favourable conditions for water confining. Both graphene-like configuration and chemical composition of basic structural elements of ShC attribute the latter to rGO fragment. The microscopic concept of the structural arrangement of ShC has been supported by the analysis of the empirical data obtained by quantum-chemical modelling [3]. Globular clusters were identified and stabilized in aqueous dispersion of ShC nanoparticles under normal conditions Substitution of water by non-polar molecular


Poster Global Graphene Forum 2016 solvents drastically changes the size and structure of the nanocarbon aggregates. Globules were transformed into stacks and flakes that are proved by SEM. The stacks were released demonstrating homogeneous distribution in the liquid crystals (LC) environment and further introduction into the cholesteric mesogenic LC matrix. This combination of LC and ShC nanoparticles revealed a decrease in the viscosity of the composites over the ranges of high strain rates and is claimed in lubricating coolant technological additives [4]. Composites based on liquid crystals seem to be promising to improve the lubricant properties of the materials over the wide friction range. The influence of the introduction of the geotribomodifier in the form of nanosized particles into engine oil of a working engine was studied. As a result of the consistent complex processing of the cylinder sleeve surfaces of engines, wear-resistant structures that combine a light sliding plane were formed, which helps to increase the resources, decrease the mechanical losses, and conserve fuel [5].

Keywords: natural graphene; shungite nanocarbon; liquid crystals, lubricant


The work was supported by the Program of the Ministry of Education and

Science of the Russian Federation in the framework of the state task for Ivanovo

State University to carry out research work in 2014

–

2016 (Grant No

4.106.2014/К)

Reference

1.

Y. Zhu, S. Murali, W. Cai., X Li., J.W. Suk, J. R Potts., R.S. Ruoff. Adv.

Mater . 22, 3906-3924, 2010 .

2.

B.S. Razbirin, N.N. Rozhkova, E.F.Sheka, D.K. Nelson, A.N.

Starukhin. JETP .145 (5), 838-8504, 2014 .

3.

E.F. Sheka, I. Natkaniec, N.N. Rozhkova, K. Holderna-Natkaniec. JETP

Letters . 99(11), 754

–

759, 2014 .

4.

N.V.

Usol’tseva

, M.V. Smirnova, A.V. Kazak, A.I. Smirnova, N.V.

Bumbina, S.O. Il’in, N.N. Rozhkova,

J. of Friction and Wear ; 36 (5),

380

–

385, 2015 .

5.

A.A. Gvozdev

, N.V. Usol’tseva, M.V. Kozinez, A.V. Kazak, A.I.

Smirnova, N.N. Rozhkova, J. of Friction and Wear , 37(2),155

–

159,

2016 .
