Increase of Electrical Conductivity due to Chemical Reduction of Pre-Exfoliated Graphene Oxide by Sodium Borohydride

2015 ◽  
Vol 1117 ◽  
pp. 187-190 ◽  
Author(s):  
Astrida Berzina ◽  
Velta Tupureina ◽  
Raimonds Orlovs ◽  
Dmitrijs Saharovs ◽  
Juris Bitenieks ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Graphene Oxide ◽  
Sodium Borohydride ◽  
Metal Ion ◽  
Large Scale ◽  
Chemical Reduction ◽  
Reduction Process ◽  
Suspension Stability ◽  
Exfoliated Graphene ◽  
Reduced Graphene

Graphene oxide (GO) reduction is a promising way for graphene large scale synthesis. Pre-exfoliated graphite was oxidized and reduced. The material was compared to commercial graphene oxide and its reduced sample. The reduction process of graphene oxide is accomplished using sodium borohydride (NaBH4) with variable-valence metal ion – cobalt – assistance. The reduced graphene oxide (RGO) was characterized by Raman spectroscopy. The particle size and suspension stability were determined. Electrical conductivity measurements of GO and RGO samples have been done in temperature range from-150°C to 85°C. Pre-exfoliation effect was determined.

Chemically reduced graphene oxide-coated knitted fabric imparted conductivity and outstanding hydrophobicity

2021 ◽  
pp. 004051752199547
Author(s):  
Min Hou ◽  
Xinghua Hong ◽  
Yanjun Tang ◽  
Zimin Jin ◽  
Chengyan Zhu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Chemical Reduction ◽  
Knitted Fabric ◽  
Mesh Structure ◽  
Reduced Graphene ◽  
Chemically Reduced Graphene Oxide ◽  
Modified Hummers Method

Functionalized knitted fabric, as a kind of flexible, wearable, and waterproof material capable of conductivity, sensitivity and outstanding hydrophobicity, is valuable for multi-field applications. Herein, the reduced graphene oxide (RGO)-coated knitted fabric (polyester/spandex blended) is prepared, which involves the use of graphite oxide (GO) by modified Hummers method and in-situ chemical reduction with hydrazine hydrate. The treated fabric exhibits a high electrical conductivity (202.09 S/cm) and an outstanding hydrophobicity (140°). The outstanding hydrophobicity is associated with the morphology of the fabric and fiber with reference to pseudo-infiltration. These properties can withstand repeated bending and washing without serious deterioration, maintaining good electrical conductivity (35.70 S/cm) and contact angle (119.39°) after eight standard washing cycles. The material, which has RGO architecture and continuous loop mesh structure, can find wide use in smart garment applications.

One-step Functionalization of Mildly and Strongly Reduced Graphene Oxide with Maleimide: An Experimental and Theoretical Investigation of the Diels-Alder [4+2] Cycloaddition Reaction

2021 ◽  
Author(s):  
Alfonso Ferretti ◽  
Sourab Sinha ◽  
Luca Sagresti ◽  
Esteban Araya-Hermosilla ◽  
Mirko Prato ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Large Scale ◽  
Cycloaddition Reaction ◽  
Diels Alder ◽  
Reduced Form ◽  
Graphene Nanocomposites ◽  
Exfoliated Graphene ◽  
Reduced Graphene ◽  
One Step

For large-scale graphene applications, such as the production of polymer-graphene nanocomposites, exfoliated graphene oxide (GO) and its reduced form (rGO) are presently considered very suitable starting material, showing enhanced chemical...

scholarly journals Back-to-Back Schottky Diode from Vacuum Filtered and Chemically Reduced Graphene Oxide

2018 ◽  
Vol 10 (3) ◽  
pp. 897
Author(s):  
Siti Nadiah Che Azmi ◽  
Shaharin Fadzli Abd Rahman ◽  
Abdul Manaf Hashim
Keyword(s):  
Ascorbic Acid ◽  
Graphene Oxide ◽  
Film Thickness ◽  
Reduced Graphene Oxide ◽  
Schottky Diode ◽  
Chemical Reduction ◽  
Process Condition ◽  
Reduction Process ◽  
Simple Method ◽  
Reduced Graphene

<span>This paper presents fabrication of reduced graphene oxide (rGO)/silicon (Si) back-to-back Schottky diode (BBSD) through graphene oxide (GO) thin film formation by vacuum filtration and chemical reduction of the film via ascorbic acid. In order to understand and assess the viability of these two processes, process condition and parameters were varied and analyzed. It was confirmed that the GO film thickness could be controlled by changing GO dispersion volume and concentration. Filtration of 200 ml of 0.4 ppm GO dispersion produced average film thickness of 53 nm. As for the reduction process, long duration was required to produce higher reduction degree. rGO film that underwent two times reduction at before and after transfer process with concentrated ascorbic acid gave the lowest sheet resistance of 3.58 MΩ/sq. In the final part of the paper, result of the BBSD device fabrication and current-voltage characterization were shown. The formed two rGO/Si Schottky junctions in the BBSD gave barrier height of 0.63 and 0.7 eV. The presented results confirmed the viability of fabricating rGO-based device using a simple method and without requirement of sophisticated equipment.</span>

EFFECT OF REDUCTION TIME ON OPTICAL PROPERTIES OF REDUCED GRAPHENE OXIDE

2017 ◽  
Vol 79 (1-2) ◽  
Author(s):  
Nur Fatihah Tajul Arifin ◽  
Madzlan Aziz
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Chemical Reduction ◽  
Reduction Process ◽  
The Other ◽  
Reduction Time ◽  
Reduced Graphene ◽  
Graphene Derivatives ◽  
Ft Ir ◽  
Epoxy Groups

Graphene and its’ derivatives received tremendous attention. The characteristics and properties of graphene made the material suitable to be used in many applications such as polymer composites, transistors and sensors. Graphene oxide (GO) and reduced graphene oxide (rGO) are few examples of graphene derivatives. GO can be synthesized in many ways. In this study, GO was produced via modified Hummer’s method. Meanwhile, sodium borohydride (NaBH4) is chosen as a reductant to further reduce the GO via chemical reduction. The material was characterized using FT-IR, UV-Vis and FESEM to observe the characteristics which occurred during the reduction process. From the FT-IR spectrum it is clearly shown that the carbonyl (C=O) and epoxy groups were eliminated on rGO. On the other hand, the band gap value of rGO reduced gradually as the reduction time increase. Besides that, the morphology of GO and rGO was also compared under the magnification of 2500x.

Green Reduction of Graphene Oxide Coated Polyamide Fabric Using Carob Extract

2020 ◽  
Vol 7 (6) ◽  
pp. 33-40
Author(s):  
Nergis Gültekin ◽  
İsmail Usta ◽  
Bahattin Yalçin
Keyword(s):  
Graphene Oxide ◽  
Chemical Reduction ◽  
Reduction Process ◽  
Dip Coating ◽  
X Ray Diffraction ◽  
Reduced Graphene ◽  
Structure Morphology ◽  
Coating Method ◽  
Polyamide Fabric ◽  
Dip Coating Method

A green reduction processes for graphene oxide using carob extract is reported in this work. In this study, graphene oxide (GO) nanosheets were synthesized using the improved Hummer's method and applied to polyamide fabric thorough the simple dip coating method. Then, the graphene oxide was reduced with a chemical reduction process using carob extract as a green reducing agent to give the reduced graphene oxide (RGO) material. The reduction time was studied. The structure, morphology, and thermal behavior of the material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA), respectively. The electrical resistivity results clearly revealed that the GO coated polyamide fabric was successfully converted to the RGO coated polyamide fabric with the effective elimination of oxygen containing functional groups.

scholarly journals Investigation of the Reduction of Graphene Oxide by Lithium Triethylborohydride

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Guangyuan Xu ◽  
Jenny Malmström ◽  
Neil Edmonds ◽  
Neil Broderick ◽  
Jadranka Travas-Sejdic ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Large Scale ◽  
Chemical Reduction ◽  
Colloidal Suspension ◽  
Cost Effective ◽  
Scale Production ◽  
Large Scale Production ◽  
Reduced Graphene ◽  
Ft Ir

The chemical reduction of a wet colloidal suspension of graphene oxide is a cost-effective and adaptable method for large scale production of “quasi” graphene for a wide variety of optoelectronic applications. In this study, modified Hummers’ procedure was used to synthesize high quality graphene oxide at 50°C. This modified protocol thus eliminates the potentially hazardous second high-temperature step in Hummers’ method for the production of GO. Furthermore, the reduction of graphene oxide by lithium triethylborohydride is demonstrated for the first time. According to FT-IR, UV-Vis, TGA, Raman, SEM/EDS, and AFM results, the reduced graphene oxide (LiEt3BH-RGO) has properties comparable to other reduced graphene oxide products reported in the literature.

scholarly journals Production of Reduced Graphene Oxide Platelets from Graphite Flakes Using the Fenton Reaction as an Alternative to Harmful Oxidizing Agents

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Jean A. V. Piñas ◽  
Tatiana S. Andrade ◽  
Andreia T. Oliveira ◽  
Pedro E. A. Salomão ◽  
Mariandry Rodriguez ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Fenton Reaction ◽  
Large Scale ◽  
Chemical Reduction ◽  
Graphene Sheets ◽  
Fenton Reagent ◽  
Fenton Chemistry ◽  
Oxidizing Agents ◽  
Reduced Graphene

The conventional chemical methods to produce graphene using strong oxidizing agents produce toxic gases during synthesis; therefore, these methods do not meet the principles of green chemistry. In this work, an alternative top-down method for the synthesis of a few layers of graphene sheets has been produced by a Fenton reaction- (a mixture of Fe2+/H2O2) assisted exfoliation process in water using graphite flakes as a starting material. Based on X-ray diffraction data and Fourier transform infrared (FTIR), Raman spectroscopy, and transmission electron microscopy measurements, it is proposed that the oxidation of graphite by Fenton chemistry facilitates the exfoliation of graphene sheets under mild sonication. Subsequent chemical reduction with ascorbic acid produced a few layers of reduced graphene oxide. Compared to Hummers’ method, the Fenton reagent has similar exfoliation efficiency, but due to the Fenton reagent’s preference to react with the edges of graphite, the chemical reduction can lead to the formation of less defective reduced graphene oxides. Moreover, since Fe and H2O2 are cheap and environmentally innocuous, their use in large-scale graphene production is environmentally friendlier than conventional methods that use toxic oxidizing agents.

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