Proton Conductivity of Graphene Oxide on Aging

2017 ◽  
Vol 70 (5) ◽  
pp. 642 ◽  
Author(s):  
Mohammad Razaul Karim ◽  
Md. Saidul Islam ◽  
Nurun Nahar Rabin ◽  
Ryo Ohtani ◽  
Masaaki Nakamura ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Functional Groups ◽  
Proton Conductivity ◽  
Photoelectron Spectroscopy ◽  
Aging Effect ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Pxrd Pattern ◽  
X Ray ◽  
Oxygenated Functional Groups

The aging effect on the proton conductivity of graphene oxide (GO) is investigated. Characterizations of oxygenated functional groups and measurement of the proton conductivity have been performed using freshly prepared GO and the same sample after preserving for three years under ambient conditions. Although GO retains its layered structure, a slight deviation in its powder X-ray diffraction (PXRD) pattern and Raman spectra upon aging implies some changes in the interlayer distance and functional groups. Decomposition of epoxy groups on aging has been recognised by X-ray photoelectron spectroscopy (XPS) analysis. The proton conductivity was found to be reduced by 25 % after three years of aging.

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

2013 ◽  
Vol 28 (2) ◽  
pp. 68-71 ◽  
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.

scholarly journals Reduced Graphene Oxide–Epoxy Grafted Poly(Styrene-Co-Acrylate) Composites for Corrosion Protection of Mild Steel

Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 666
Author(s):  
Xinchuan Fan ◽  
Yue Hu ◽  
Yijun Zhang ◽  
Jiachen Lu ◽  
Xiaofeng Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
X Ray Diffraction ◽  
Corrosion Properties ◽  
X Ray ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Scanning Electron

Reduced graphene oxide–epoxy grafted poly(styrene-co-acrylate) composites (GESA) were prepared by anchoring different amount of epoxy modified poly(styrene-co-acrylate) (EPSA) onto reduced graphene oxide (rGO) sheets through π–π electrostatic attraction. The GESA composites were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The anti-corrosion properties of rGO/EPSA composites were evaluated by electro-chemical impedance spectroscopy (EIS) in hydroxyl-polyacrylate coating, and the results revealed that the corrosion rate was decreased from 3.509 × 10−1 to 1.394 × 10−6 mm/a.

scholarly journals Structural Characterization of Graphene Oxide: Surface Functional Groups and Fractionated Oxidative Debris

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1180 ◽  
Author(s):  
Elvin Aliyev ◽  
Volkan Filiz ◽  
Muntazim M. Khan ◽  
Young Joo Lee ◽  
Clarissa Abetz ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Functional Groups ◽  
Structural Model ◽  
Oxide Surface ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
Surface Functional Groups ◽  
X Ray ◽  
Transmission Electron

The purpose of this work is the structural analysis of graphene oxide (GO) and by means of a new structural model to answer the questions arising from the Lerf–Klinowski and the Lee structural models. Surface functional groups of GO layers and the oxidative debris (OD) stacked on them were investigated after OD was extracted. Analysis was performed successfully using Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), X-ray photoemission spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, solid-state nuclear magnetic resonance spectroscopy (SSNMR), standardized Boehm potentiometric titration analysis, elemental analysis, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The analysis showed that graphene oxide layers, as well as oxidative debris contain different functional groups such as phenolic –OH, ketone, lactone, carboxyl, quinone and epoxy. Based on these results, a new structural model for GO layers is proposed, which covers all spectroscopic data and explains the presence of the other oxygen functionalities besides carboxyl, phenolic –OH and epoxy groups.

scholarly journals Isotherm and Kinetic Modeling of Strontium Adsorption on Graphene Oxide

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2780
Author(s):  
Abdulrahman Abu-Nada ◽  
Ahmed Abdala ◽  
Gordon McKay
Keyword(s):  
Graphene Oxide ◽  
Aqueous Solutions ◽  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Nitrogen Adsorption ◽  
Order Kinetic ◽  
X Ray ◽  
Oxygen Functional Groups ◽  
Bet Analysis

In this study, graphene oxide (GO) was synthesized using Hummers method. The synthesized GO was characterized using field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) nitrogen adsorption. The analyses confirmed the presence of oxygen functional groups (C=O and C-O-C) on the GO surface. These oxygen functional groups act as active sites in the adsorption Sr (II). The BET analysis revealed the surface area of GO of 232 m2/g with a pore volume of 0.40 cm3/g. The synthesized GO was used as an adsorbent for removing Sr (II) from aqueous solutions. The adsorption equilibrium and kinetic results were consistent with the Langmuir isotherm model and the pseudo-second-order kinetic model. A maximum strontium adsorption capacity of 131.4 mg/g was achieved. The results show that the GO has an excellent adsorption capability for removing Sr (II) from aqueous solutions and potential use in wastewater treatment applications.

scholarly journals Degradation of acetamiprid using graphene-oxide-based metal (Mn and Ni) ferrites as Fenton-like photocatalysts

2020 ◽  
Vol 81 (1) ◽  
pp. 178-189 ◽  
Author(s):  
Asma Tabasum ◽  
Ijaz Ahmad Bhatti ◽  
Nimra Nadeem ◽  
Muhammad Zahid ◽  
Zulfiqar Ahmad Rehan ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Advanced Oxidation Process ◽  
Irradiation Time ◽  
Wastewater Remediation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Optimization Study ◽  
Excellent Activity ◽  
Oxide Composites

Abstract This study aims to explore the photocatalytic potential of graphene-oxide-based metal ferrites for the degradation of acetamiprid (an odorless neonicotinoid pesticide). Metal (Mn and Ni) ferrites (along with their graphene oxide composites) were prepared by the hydrothermal method while graphene oxide (GO) was synthesized using a modified Hummer's method. The composites were characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The photocatalysts were studied for their Fenton-like advanced oxidation process to degrade acetamiprid. The composites showed excellent activity against acetamiprid degradation (>90%) in 60 min under UV irradiation. The detailed optimization study was carried out to investigate the influential variables (such as pH, catalyst dose, pollutant concentration, irradiation time, oxidant dose, etc.) to achieve enhanced degradation efficiency. Moreover, the findings were endorsed by central composite design (CCD). It was concluded that degradation was enhanced in an appropriate combination of photocatalyst and hydrogen peroxide. The magnetic character of the metal ferrites and their composites played an important role in the easy separation and reusability of these materials. The present findings result in highly effective, easy to handle and stable heterogeneous photo-Fenton materials for wastewater remediation.

A Mild and Efficient Approach for the Reduction of Graphene Oxide

2013 ◽  
Vol 652-654 ◽  
pp. 206-209
Author(s):  
Yu Feng Wang ◽  
Chun Hua Han ◽  
Bao Liu ◽  
Dong Mei Zhao ◽  
Dong Yu Zhao ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Efficient Approach ◽  
Low Toxicity

A mild and efficient approach for the reduction of graphene oxide by NaHTe is reported in this work. This reductant is of low toxicity and nonvolatile and it reduce GO to graphene at room temperature in 2h. X-ray diffraction results showed that NaHTe can reduce GO completely in shorter time, comparing with hydroxylamine. Furthermore, X-ray photoelectron spectroscopy also indicates the reduction of GO to grapheme.

Preparation and characterization of graphene oxide/PMMA nanocomposites with amino-terminated vinyl polydimethylsiloxane phase interfaces

2016 ◽  
Vol 36 (9) ◽  
pp. 867-875 ◽  
Author(s):  
Hongyan Li ◽  
Weian Wang ◽  
Lin Cheng ◽  
Jing Li ◽  
Yajing Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Bending Strength ◽  
X Ray Diffraction ◽  
X Ray ◽  
Three Point Bending ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Amidation Reaction

Abstract Graphene oxide (GO) was prepared by the Hummers method and was grafted by an amino-terminated vinyl polydimethylsiloxane (AP). The AP-modified GO (GO-AP) was incorporated in poly(methylmethacrylate) (PMMA) to prepare nanocomposites. Raman microscopy, Fourier transformed infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analysis were used to characterize the particles. The mechanical properties, thermal stability, thermal conductivity, and dispersing status of the PMMA-based nanocomposites were also investigated. The results indicated that AP was grafted on the surface of GO via the amidation reaction, and the quantity of the grafted AP was approximately 20 wt% that of GO-AP. With the addition of GO-AP, the three-point bending strength of GO-AP/PMMA increased to approximately 58 MPa, and the dispersion of the particles was also enhanced. GO wrapped by AP could not form thermal conducting networks at the percolation thresholds. The increasing amount of AP prevented the formation of thermal conduction network and decreased the thermal conductivity of the composites. The thermal stability of the composites was affected by three main reasons, and the total effect of the three reasons on thermal stability illustrated a negative trend.

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

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.

Photocatalytic Degradation of Indigo Carmine by ZnO-Cu2O/Graphene Oxide Composites Synthesized via Hydrothermal Method

2013 ◽  
Vol 668 ◽  
pp. 105-109 ◽  
Author(s):  
Huai Di Wu ◽  
Lu Sheng Chen ◽  
Jin Chao Hu
Keyword(s):  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Hydrothermal Method ◽  
Photoelectron Spectroscopy ◽  
Indigo Carmine ◽  
Synthesis Temperature ◽  
X Ray Diffraction ◽  
Synthesis Time ◽  
X Ray ◽  
Oxide Composites

In this work, ZnO–Cu2O/graphene oxide (GO) composites have been synthesized by using simple hydrothermal method. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to characterize the crystal structure and composite elements. The photocatalytic activity of the composites has been conducted by measuring the degradation of indigo carmine under UV irradiation. When the atom ratio of Zn/Cu is 5/2, 120 °C of hydrothermal synthesis temperature and 20 h of synthesis time, the ZnO/Cu2O/GO composite exhibits good photocatalytic activity with 96.5% degradation rate of indigo carmine aqueous solution under 500 W high pressure Hg lamp irradiation for 240 min.

scholarly journals Synthesis and Characterization of Graphene Oxide/Chitosan Composite Aerogels with High Mechanical Performance

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 777 ◽  
Author(s):  
Yang Gong ◽  
Yingchun Yu ◽  
Huixuan Kang ◽  
Xiaohong Chen ◽  
Hao Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Mechanical Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Composite Aerogels ◽  
Mercury Porosimeter ◽  
Chitosan Composite

Chitosan, a semi-crystalline biomolecule, has attracted wide attention due to its high synthesis flexibility. In this study, to improve the mechanical properties of chitosan aerogels (CSAs), graphene oxide (GO) was extracted and introduced into chitosan aerogels as fillers. The porous CSAs/GO composite aerogels were fabricated by an environmentally friendly freeze-drying process with different GO contents (0, 0.5, 1.0, 1.5, wt.%). The characteristics of the CSAs/GO were investigated by scanning electron microscopy (SEM), mechanical measurements and mercury porosimeter. The crystallinity of samples was characterized by X-ray diffraction (XRD). The mechanism of the effect of graphene oxide on chitosan was studied by Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results show that the microstructure of the samples is developed in the network structure. The porosity of CSAs/GO aerogels is as high as 87.6%, and the tensile strength of the films increased from 6.60 MPa to 10.56 MPa with the recombination of graphene oxide. The crystallinity (CrI) of composite aerogels increased from 27% to 81%, which indicates that graphene oxide improves the mechanical properties of chitosan by chemical crosslinking.

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