Synthesis of Graphene Oxide Nanosheets via Modified Hummers’ Method and Its Physicochemical Properties

2015 ◽  
Vol 74 (1) ◽  
Author(s):  
Mohamad Fahrul Radzi Hanifah ◽  
Juhana Jaafar ◽  
Madzlan Aziz ◽  
Ahmad Fauzi Ismail ◽  
Mukhlis A. Rahman ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Physicochemical Properties ◽  
Functional Groups ◽  
Interlayer Spacing ◽  
Graphene Oxide Nanosheets ◽  
Hummers Method ◽  
Exfoliated Graphene ◽  
Transmission Electron ◽  
Direct Methanol ◽  
Modified Hummers Method

The efficient synthesis of exfoliated graphene oxide nanosheets (GO) via modified Hummers’ method was successfully carried out. The physicochemical properties of GO were determined by Fourier transform infrared spectroscopy (FTIR), UV-visible spectrophotometry (UV-vis), x-ray diffraction analysis (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). The graphite was fully oxidized by strong oxidizing agent caused the oxygen-containing functional groups such as C-O-C, C=O, and COOH were introduced into the graphite layers as analyzed by Raman and FTIR.  XRD pattern of GO showed 2θ of 12.0o with interlayer spacing ~ 7.37A which describe non uniform crystal structure with the addition of oxygen containing functional groups. UV-vis spectrum of GO exhibit maximum absorption peak at ~ 234 nm corresponding to the aromatic C=C bond with π-π* transition. The morphology of GO was observed to have flake-like shape and less transparent layers by TEM. The properties of synthesized GO suggest high potential in producing the high quality of graphene which is can be applied as the electrocatalyst support for direct methanol fuel cell application.              

Enhancement of Hydrophobility and Thermal Property of Graphene Oxide by Paratoluidine Chemical Functionalization

2014 ◽  
Vol 809-810 ◽  
pp. 243-247
Author(s):  
Zhi Jia Luo ◽  
Hong Zhang Geng ◽  
Song Ting Zhang ◽  
Bao Tan Du ◽  
Xing Zhang ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Graphene Oxide ◽  
Thermal Property ◽  
Functional Groups ◽  
Drug Delivery Systems ◽  
Graphite Powder ◽  
Hydroxyl Groups ◽  
Chemical Functionalization ◽  
Hummers Method ◽  
Modified Hummers Method

Graphene oxide (GO) is typically synthesized by graphite powder under strong oxidizing reaction, possessing with the same set of functional groups: epoxy and hydroxyl in basal plane and carboxyl and hydroxyl groups existence on the flake edges which endow GO with amphipathy. GO and its functionalized derivatives have been successfully tested in many domains, such as polymer composites, biosensors, drug delivery systems, etc. In this paper, GO was prepared by a modified Hummers method employing improved process (preparation and separation), aiming at industrialization with the lowest cost. Moreover, some novel functional groups with different properties were controlled chemically grafted onto GO to modify the wettability and reaction activity with other materials. The hydrophobicity and the thermal property of graphene oxide were enhanced by chemical functionalization.

Top-Down Fabrication of Superhydrophilic Graphene Oxide Nanosheets

2016 ◽  
Vol 849 ◽  
pp. 738-742
Author(s):  
Xue Bing Hu ◽  
Yun Yu ◽  
Wen Xiou Ding ◽  
Zhou Hao Xiao ◽  
Yong Qing Wang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Graphene Oxide ◽  
Chemical Oxidation ◽  
Monolayer Graphene ◽  
Graphene Oxide Nanosheets ◽  
Top Down ◽  
Laminar Structure ◽  
Water Contact ◽  
Hummers Method ◽  
Modified Hummers Method

As an oxidized form of graphene, graphene oxide has a variety of oxygen-containing groups together with a laminar structure, showing great potential in various engineering applications. In this work, on the basis of the top-down fabrication principle, superhydrophilic graphene oxide nanosheets with a uniform sheet size of ~50 nm diameter and 0.7 nm thickness were prepared by the modified Hummers method, and using microcrystalline graphite as the carbon source. After chemical oxidation, the obtained graphene oxide nanosheets had a great amount of C-O-C, C-OH and C=O groups and its water contact angle was ~3.9°. This result offers a facile strategy to fabricate superhydrophilic and monolayer graphene oxide nanosheets with well-defined morphology.

Graphene Oxide Prepared via Ultrasonic Assisted Chemical Oxidation Method and its Fluorescence Property

2014 ◽  
Vol 986-987 ◽  
pp. 84-87
Author(s):  
Yan Qun Cui ◽  
Ze Wu ◽  
Li Min Dong ◽  
Qin Li ◽  
Zhi Dong Han
Keyword(s):  
Graphene Oxide ◽  
Emission Spectra ◽  
Interlayer Spacing ◽  
Chemical Oxidation ◽  
Fluorescence Property ◽  
Oxidation Method ◽  
Hummers Method ◽  
Ultrasonic Assisted ◽  
Modified Hummers Method

Graphene oxide (GO) was prepared via ultrasonic assisted chemical oxidation method. Contrasting with modified hummers method, GO prepared by ultrasonic assisted chemical oxidation method showed thinner flakes, the interlayer spacing increases. The emission spectra of the GO showed a similar excitation-dependent feature with the strongest peak (552 nm) excited at 477 nm.

scholarly journals Effects of gaseous environments on physicochemical properties of thermally exfoliated graphene oxides for hydrogen storage: A comparative study

2021 ◽  
Author(s):  
Sohan Bir Singh ◽  
Mahuya De
Keyword(s):  
Graphene Oxide ◽  
Hydrogen Storage ◽  
Physicochemical Properties ◽  
Surface Area ◽  
Functional Groups ◽  
Layered Structure ◽  
Pore Volume ◽  
Average Pore Size ◽  
Average Pore ◽  
Exfoliated Graphene

Abstract The present study compared the effect of different gaseous environments on physicochemical properties and subsequent hydrogen storage ability of thermally exfoliated graphene oxide (EGO). The reducing, inert or oxidizing environments were generated using hydrogen, argon or air as the carrier gas, respectively. The structure of thermally exfoliated graphene oxide depended on the type of gaseous environment. The EGO prepared in presence of Air showed the fluffiest layered structure having highest surface area. The surface area order was EGO(Air) (268 m2/g) > EGO(H2) (248 m2/g) > EGO(Ar) (155 m2/g). The average pore sizes of EGO(Air) and EGO(H2) were 2.9 and 2.8 nm, with pore volumes of 1.2 and 1.6 cm3/g, respectively. The average pore size for EGO(Ar) was highest at 4.1 nm, associated with presence of larger void space and lowest total pore volume of 1.0 cm3/g. Thus, presence of oxidative or reducing atmosphere seemed to be more conducive to exfoliation of layers by gradual removal of functional groups. The inert atmosphere of argon caused severe thermal separation of layers and functional groups, adversely affecting the layered structure as observed. The EGO(Air) also showed highest O/C ratio suggesting presence of significant amount of oxygen–containing functional groups on the surface. The hydrogen uptake order at 77 K and 30 bar was: EGO (Air) 3.34 wt.% > EGO (H2) 3.12 wt.% > EGO (Ar) 2.2 wt.%. The highest uptake of EGO(Air) might have resulted from highest surface area, highest O/C ratio and presence of considerable pore volume.

scholarly journals Influence of Process Parameters in Graphene Oxide Obtention on the Properties of Mechanically Strong Alginate Nanocomposites

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1081 ◽  
Author(s):  
Izaskun Larraza ◽  
Lorena Ugarte ◽  
Aintzane Fayanas ◽  
Nagore Gabilondo ◽  
Aitor Arbelaiz ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Sodium Alginate ◽  
Graphene Sheets ◽  
Influence Of Process Parameters ◽  
Size Dependent ◽  
Hummers Method ◽  
Exfoliated Graphene ◽  
Enhanced Properties ◽  
Modified Hummers Method

Sodium alginate, a biopolymer extracted from brown algae, has shown great potential for many applications, mainly due to its remarkable biocompatibility and biodegradability. To broaden its fields of applications and improve material characteristics, the use of nanoreinforcements to prepare nanocomposites with enhanced properties, such as carbonaceous structures which could improve thermal and mechanical behavior and confer new functionalities, is being studied. In this work, graphene oxide was obtained from graphite by using modified Hummers’ method and exfoliation was assisted by sonication and centrifugation, and it was later used to prepare sodium alginate/graphene oxide nanocomposites. The effect that different variables, during preparation of graphene oxide, have on the final properties has been studied. Longer oxidation times showed higher degrees of oxidation and thus larger amount of oxygen-containing groups in the structure, whereas longer sonication times and higher centrifugation rates showed more exfoliated graphene sheets with lower sizes. The addition of graphene oxide to a biopolymeric matrix was also studied, considering the effect of processing and content of reinforcement on the material. Materials with reinforcement size-dependent properties were observed, showing nanocomposites with large flake sizes, better thermal stability, and more enhanced mechanical properties, reaching an improvement of 65.3% and 83.3% for tensile strength and Young’s modulus, respectively, for a composite containing 8 wt % of graphene oxide.

scholarly journals Effect of long-term ageing on graphene oxide: structure and thermal decomposition

2021 ◽  
Vol 8 (12) ◽  
Author(s):  
Chen Li ◽  
Yanling Lu ◽  
Jun Yan ◽  
Weibo Yu ◽  
Ran Zhao ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Graphene Oxide ◽  
Apparent Activation Energy ◽  
Functional Groups ◽  
Defect Density ◽  
Oxide Structure ◽  
Hummers Method ◽  
Modified Hummers Method

After long-term ageing, the structure of graphene oxide prepared by the modified Hummers method changed. Because of the desorption of oxygen-containing functional groups, the C/O ratio of graphene oxide increased from 1.96 to 2.76. However, the average interlayer distance decreased from 0.660 to 0.567 nm. The content of -CH- and -CH 2 - decreased; however, the type of oxygen-containing functional groups did not change. Moreover, I D / I G increased from 0.87 to 0.92, indicating that the defect density decreased because of desorbing oxygen functional groups after ageing. When the temperature exceeded 60°C, CO 2 produced by decomposing graphene oxide was detected. The thermal decomposition changed after ageing. The decomposition peak temperature decreased from 216°C to 195°C. The CO 2 amount produced remained almost unchanged; however, the amount of CO, SO 2 and H 2 O decreased. After ageing, the apparent activation energy of graphene oxide decreased from 150 to 134 kJ mol −1 .

Graphene Oxide as a Substrate for Biosensors: Synthesis and Characterization

2021 ◽  
Vol 324 ◽  
pp. 87-93
Author(s):  
Mohamed Adel ◽  
Abdel Hady A. Abdel-Wahab ◽  
Ahmed Abdel-Mawgood ◽  
Ahmed Osman Egiza
Keyword(s):  
Raman Spectroscopy ◽  
Graphene Oxide ◽  
Acidic Solution ◽  
Cost Effective ◽  
Sem Analysis ◽  
Visible Spectroscopy ◽  
Sem Images ◽  
Hummers Method ◽  
Uv Visible ◽  
Modified Hummers Method

Graphene oxide (GO) is an oxidized nanosheets of graphite with a 2D planar structure. GO could be readily complexed with bio-entities as it possesses many oxygen-containing functionalities on its surface. The preparation process is fast, easy, and cost-effective. It was prepared using modified Hummers’ method in acidic solution as a primary solvent and potassium permanganate as an oxidizing agent. Afterwards, it was successfully characterized by FTIR, UV-visible spectroscopy, as well as XRD and Raman spectroscopy, and finally, SEM analysis. It was observed that the formed GO is mainly composed of carbon and oxygen elements rich in oxygen functional groups. Furthermore, the existence of (001) plane in XRD interprets the complete oxidation of graphite with d-spacing 9 Å. Moreover, Raman spectroscopy displayed the sp3 carbon hybridization, besides, the ID/IG ratio is found to be 0.84, which confirms the disorder between graphene oxide layers. The SEM images also pointed out that graphene oxide sheets were regularly stacked together as flake-like structures. Accordingly, the richness of oxygen-containing functionalities was confirmed. Hence, it is appropriate to be used as a base transducer for biosensing applications.

The Synthesis and Characterization of the Graphene Oxide Covalent Modified Phenolic Resin Nanocomposites

2011 ◽  
Vol 327 ◽  
pp. 115-119 ◽  
Author(s):  
Duo Wang ◽  
Jie Gao ◽  
Wei Fang Xu ◽  
Feng Bao ◽  
Rui Ma ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Phenolic Resin ◽  
Synthesis And Characterization ◽  
Infrared Spectrometry ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Hummers Method ◽  
Modified Hummers Method ◽  
Thermal Stability Of

Graphene oxide (GO) was made by a modified Hummers method. Graphene oxide modified phenolic resin nanocomposites (GO/PF) were prepared by Steglich esterification, catalyzed by dicyclohexyl carbodiimide and 4-dimethylaminopyridine. The composites were characterized by Fourier transform infrared spectrometry, differential scanning calorimetry, X-ray powder diffraction, and scanning electron microscopy. The result revealed that the graphene oxide was absolutely exfoliated and covalent linked GO/PF composite was obtained. The thermal stability of PF is remarkably improved by modification with GO.

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