Preparation of Graphene Oxide from Expanded Graphite at Different Microwave Heating Times

Exfoliated graphite (EG) was prepared by mixing graphite with HNO3 and KMnO4 at weight ratio 1:2:1 using microwave heating at times 20, 60, 80 and 120 sec. Graphene oxide (GO) was then prepared using EG as precursor by the modified Hummer’s method. Atomic force microscopy (AFM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy analyses showed successful conversion of EG into GO. The XRD results of the GO showed that the maximum interplanar distance (d-spacing) increased from 0.344 to 0.831 nm. The AFM showed a minimum thickness of 0.519 nm for a single layer of GO prepared from EG 80 sec. The XRD examination also showed an increase in the d-spacing between the GO layers after sonication compared to before sonication.

Download Full-text

Characterization of X-ray irradiated graphene oxide coatings using X-ray diffraction, X-ray photoelectron spectroscopy, and atomic force microscopy

Powder Diffraction ◽

10.1017/s0885715613000109 ◽

2013 ◽

Vol 28 (2) ◽

pp. 68-71 ◽

Cited By ~ 40

Author(s):

Thomas N. Blanton ◽

Debasis Majumdar

Keyword(s):

Atomic Force Microscopy ◽

Graphene Oxide ◽

Photoelectron Spectroscopy ◽

High Energy ◽

X Ray Diffraction ◽

Carbon Phase ◽

X Ray ◽

Force Microscopy ◽

Atomic Force ◽

Before And After

In an effort to study an alternative approach to make graphene from graphene oxide (GO), exposure of GO to high-energy X-ray radiation has been performed. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) have been used to characterize GO before and after irradiation. Results indicate that GO exposed to high-energy radiation is converted to an amorphous carbon phase that is conductive.

Download Full-text

Improvement of Interface Roughness in Platinum/Carbon Multilayers for X-Ray Mirrors

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.523-524.1076 ◽

2012 ◽

Vol 523-524 ◽

pp. 1076-1079

Author(s):

Jang Woo Kim ◽

Satoshi Matsuyama ◽

Yasuhisa Sano ◽

Kazuto Yamauchi

Keyword(s):

Surface Roughness ◽

Single Layer ◽

Interface Roughness ◽

Carbon Doping ◽

Diffraction Spectrum ◽

X Ray Diffraction ◽

Sputtering Deposition ◽

X Ray ◽

Force Microscopy ◽

Atomic Force

We present a study of the improvement in interface roughness of platinum/carbon multilayers for X-ray mirrors. The X-ray reflectivity of multilayers strongly depends on interface quality. In an effort to reduce the interface roughness caused by crystallization during deposition, carbon doping of platinum was proposed, and its effectiveness was evaluated. We compared 45-nm-thick single-layer platinum to carbon-doped platinum films. The films were deposited on a silicon (100) substrate by dc magnetron sputtering deposition. The surface roughness and X-ray diffraction spectrum of each film were measured by atomic force microscopy and X-ray diffraction, respectively. We concluded that the increase in carbon concentration suppresses the crystallization of platinum and causes the surface roughness to decrease.

Download Full-text

Synthesis and Characterization of Graphene Thin Films by Chemical Reduction of Exfoliated and Intercalated Graphite Oxide

Journal of Chemistry ◽

10.1155/2013/150536 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6 ◽

Cited By ~ 87

Author(s):

F. T. Thema ◽

M. J. Moloto ◽

E. D. Dikio ◽

N. N. Nyangiwe ◽

L. Kotsedi ◽

...

Keyword(s):

Graphene Oxide ◽

Chemical Reduction ◽

Reduction Process ◽

Colloidal Dispersion ◽

Functionalized Graphene ◽

X Ray Diffraction ◽

Functionalized Graphene Oxide ◽

Force Microscopy ◽

Atomic Force ◽

Polar Aprotic Solvent

Commercial flakes of graphite were prepared into functionalized graphene oxide (GO) by chemical treatment. After the exfoliation and intercalation of graphene into functionalized graphene oxide that formed stable colloidal dispersion in polar aprotic solvent, the reduction process was undertaken by continuous stirring with hydrazine hydrate. The reduced material was characterized by X-ray diffraction (XRD), attenuated total reflectance (ATR) FT-IR, ultraviolet visible (UV-vis), atomic force microscopy (AFM) and Raman spectroscopy which confirm the oxidation of graphite and reduction of graphene oxide into graphene sheet.

Download Full-text

Enhancement of barrier and anti-corrosive performance of zinc-rich epoxy coatings using nano-silica/graphene oxide hybrid

Corrosion Reviews ◽

10.1515/corrrev-2020-0034 ◽

2020 ◽

Vol 38 (6) ◽

pp. 497-513

Author(s):

Meiling Zhang ◽

Hui Wang ◽

Ting Nie ◽

Jintao Bai ◽

Fei Zhao ◽

...

Keyword(s):

Electron Microscopy ◽

Graphene Oxide ◽

Corrosion Protection ◽

Electrochemical Impedance ◽

Epoxy Coating ◽

X Ray Diffraction ◽

Protection Efficiency ◽

Force Microscopy ◽

Atomic Force ◽

Transmission Electron

AbstractThis study reports a facile method to prepare silica-coated graphene oxide nanoflakes (SiO2–GO). Results of X-ray diffraction analysis, Raman spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and atomic force microscopy reveal that silica was successfully coated on the GO flakes. The effect of SiO2–GO nanosheets on the corrosion protection and barrier performance of the epoxy coating was investigated in this work. Results indicate that the mechanical properties of all coatings added with GO and SiO2–GO were significantly improved. Furthermore, electrochemical impedance and Tafer polarisation curves showed that added 0.5 wt% SiO2–GO nanoflakes into zinc-rich epoxy coating could greatly improve the anti-corrosion performance of the sample, and the corrosion protection efficiency increased from 67.01 to 99.58%.

Download Full-text

Synthesis of Graphene Oxide Nanoparticles by Laser Ablation System

Iraqi Journal of Science ◽

10.24996/ijs.2020.61.9.11 ◽

2020 ◽

pp. 2241-2250

Author(s):

Atiaf K. Jeryo ◽

Qusay Adnan Abbas

Keyword(s):

Magnetic Field ◽

Graphene Oxide ◽

X Ray Diffraction ◽

Force Microscopy ◽

Fundamental Wavelength ◽

Atomic Force ◽

Pure Graphite ◽

Reduced Graphene ◽

Stretching Vibration ◽

Pulse Energies

In this study, graphene oxide (GO) and reduced graphene oxide were synthesized by pulsed Nd:YAG laser with a fundamental wavelength (1064 nm) focused on the pure graphite target which was immersed in distilled water. Different pulse energies were applied in two cases; with and without magnetic field. The synthesized GO and rGO nanoparticles were characterized by UV-visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and atomic force microscopy (AFM) with and without magnetic field. The data show the presence of a magnetic field which illustrated increasing oxygen functional groups of GO. This caused a change in the morphology of the surface of GO, increasing crystallite size from 12.19 nm to 71.2 nm. The interlayer distance (d-space) was reduced from 0.4 nm to 0.25 nm and the absorption peaks that appeared in the spectrum were reduced and shifted toward smallest wavelengths, while the stretching vibration of the O-H group peak was shifted toward largest wavelengths.

Download Full-text

A Review on Common Methods for Characterizing Graphene Oxide (GO)

Asian Journal of Applied Chemistry Research ◽

10.9734/ajacr/2019/v4i230109 ◽

2019 ◽

pp. 1-8

Author(s):

Md. Shafiul Islam

Keyword(s):

Graphene Oxide ◽

Photoelectron Spectroscopy ◽

Chemical Structure ◽

X Ray Diffraction ◽

X Ray ◽

Force Microscopy ◽

The Past ◽

Atomic Force ◽

Scientific World ◽

Uv Visible

Graphene oxide, two-dimensional material with the thickness of 1.1±0.2 nm, has gained attention to a greater extent in the field of science for its radically distinctive properties: physical, chemical, optical as well as electrical etc. Graphene oxide (monolayer sheet) has been synthesized by oxidizing graphite (millions of layer) to graphite oxide (multilayers) which has been converted into graphene oxide via exfoliation followed by sonication and centrifugation - a method mentioned as Modified Hummer Method. I focus on the chemical structure of graphene oxide. However, I discuss the different analytical methods such as UV-Visible spectroscopy, Atomic Force Microscopy (AFM), X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR) as well as X-ray Diffraction pattern for characterizing the graphene oxide. Furthermore, this review covers the analytical evaluation of graphene oxide and discuss the past, present and future of graphene oxide in the scientific world.

Download Full-text

Micro Scalable Graphene Oxide Productions Using Controlled Parameters in Bench Reactor

Nanomaterials ◽

10.3390/nano11081975 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1975

Author(s):

Carolina S. Andrade ◽

Anna Paula S. Godoy ◽

Marcos Antonio Gimenes Benega ◽

Ricardo J. E. Andrade ◽

Rafael Cardoso Andrade ◽

...

Keyword(s):

Graphene Oxide ◽

Photoelectron Spectroscopy ◽

Scale Up ◽

Physicochemical Characteristics ◽

Structural Quality ◽

X Ray Diffraction ◽

X Ray ◽

Force Microscopy ◽

Atomic Force ◽

Process Reproducibility

The detailed study of graphene oxide (GO) synthesis by changing the graphite/oxidizing reagents mass ratios (mG/mROxi), provided GO nanosheets production with good yield, structural quality, and process savings. Three initial samples containing different amounts of graphite (3.0 g, 4.5 g, and 6.0 g) were produced using a bench reactor under strictly controlled conditions to guarantee the process reproducibility. The produced samples were analyzed by Raman spectroscopy, atomic force microscopy (AFM), x-ray diffraction (XDR), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR) and thermogravimetry (TGA) techniques. The results showed that the major GO product comprised of nanosheets containing between 1–5 layers, with lateral size up to 1.8 µm with high structural quality. Therefore, it was possible to produce different batches of graphene oxide with desirable physicochemical characteristics, keeping the amount of oxidizing reagent unchanged. The use of different proportions (mG/mROxi) is an important strategy that provides to produce GO nanostructures with high structural quality and scale-up, which can be well adapted in medium-sized bench reactor.

Download Full-text

SYNTHESIS OF GRAPHENE OXIDE USING MILDLY OXIDIZED GRAPHITE THROUGH ULTRASONIC EXFOLIATION

Surface Review and Letters ◽

10.1142/s0218625x17500871 ◽

2016 ◽

Vol 24 (06) ◽

pp. 1750087

Author(s):

YANG HU ◽

ZHUANG LI ◽

HONGQIANG LI ◽

SHAOXIAN SONG ◽

ALEJANDRO LOPEZ-VALDIVIESO

Keyword(s):

Graphene Oxide ◽

Direct Method ◽

Reaction System ◽

X Ray Diffraction ◽

Oxidation Degree ◽

X Ray ◽

Force Microscopy ◽

Atomic Force ◽

Oxidized Graphite ◽

Ultrasonic Homogenizer

This study investigated the preparation of graphene oxide from mildly oxidized graphite through ultrasonic exfoliation. Both the original and produced materials were analyzed by ultraviolet–visible spectrophotometer, X-ray diffraction and atomic force microscopy. The results indicated that the exfoliation yield of graphene oxide was proportional to the input ultrasonic energy. In addition, a two-stage exfoliation phenomenon was observed in the exfoliation of mildly oxidized graphite with both ultrasonic homogenizer and cleaner. It also was found that increasing the content of [[Formula: see text]] in a C–H2SO4–[[Formula: see text]] reaction system was the most simple and direct method to increase the oxidation degree of graphite oxide.

Download Full-text

Preparation and Characterization of Protein-Montmorillonite Composites

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.184-185.1120 ◽

2012 ◽

Vol 184-185 ◽

pp. 1120-1123

Author(s):

Qian Zhu ◽

Dai Mei Chen ◽

Yan Liu ◽

Xu Tao Deng ◽

Hui Li ◽

...

Keyword(s):

Interlayer Space ◽

Weight Ratio ◽

Gravimetric Analysis ◽

Thermal Gravimetric ◽

X Ray Diffraction ◽

X Ray ◽

Force Microscopy ◽

Intercalation Reaction ◽

Atomic Force

Protein-montmorillonite composites were prepared by direct and stepwise intercalation of lysozyme(LYZ) into gallery of montmorillonite(MMT), and characterized by X-ray Diffraction (XRD), Thermal Gravimetric Analysis(TGA) and Atomic Force Microscopy(AFM). The direct intercalation experiment showed that with the increase of LYZ/MMT weight ratio from 1:1 to 4:1, the interlayer space of MMT increased from 4.2nm to 6.3nm, and the adsorption amount of lysozyme onto MMT increased from 1.05mg/mg to 1.84mg/mg. While in stepwise intercalation process, the adsorption of LYZ was obviously lower than that in direct intercalation experiment, indicating that the exchange reaction between lysozyme and POP-D2000 was incomplete in the stepwise intercalation reaction.

Download Full-text