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.

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>

scholarly journals Facile Techniques to Synthesize Reduced Graphene Oxide for Removing Tetracycline From Water: Kinetics and Thermodynamics Studies

2021 ◽  
Author(s):  
Trinh Tran Dinh ◽  
Thi-My-Trinh Ha ◽  
Thi-An-Hang Nguyen ◽  
Viet-Cuong Dang ◽  
Van-Duong Dao
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Adsorption Process ◽  
Reduction Process ◽  
Chemical Oxidation ◽  
Mild Conditions ◽  
Reduced Graphene ◽  
Langmuir Isotherm Model ◽  
Ft Ir ◽  
Synthesized Materials

Abstract In this study, reduced graphene oxide (rGO) was successfully produced from graphite precursor by chemical oxidation and exfoliation processes which were followed by a reduction process in mild conditions. rGO was then applied in the adsorption of tetracycline (TC) in water. SEM/EDX, XRD, FT-IR, BET, pHpzc were conducted to characterize the synthesized materials. The adsorption efficiency of TC from water was evaluated by changes in several factors such as contact time, temperature, pH of the solution, adsorbent load, and tetracycline concentration. Furthermore, adsorption kinetics, thermodynamics, and isotherms were also investigated. As the result, the adsorption process of TC onto rGO was spontaneous, endothermic, and governed by both physisorption and chemisorption. The maximum uptake calculated from Langmuir isotherm model was 58.03 mg/g. rGO material could be regenerated by using methanol and diluted NaOH solutions. The findings in this work provides a complete data on the TC adsorption process onto rGO and the process of recovery and reuse of rGO.

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 Magnetization of Ultraviolet-Reduced Graphene Oxide Flakes in Composites Based on Polystyrene

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2519
Author(s):  
Alexander N. Ionov ◽  
Mikhail P. Volkov ◽  
Marianna N. Nikolaeva ◽  
Ruslan Y. Smyslov ◽  
Alexander N. Bugrov
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Reduction Process ◽  
X Ray Diffraction ◽  
Mesoscopic Structure ◽  
Reduced Graphene ◽  
Study Results ◽  
Edge Defects ◽  
Mesoscopic Level ◽  
Ferromagnetic Hysteresis

This work presents our study results of the magnetization of multilayer UV-reduced graphene oxide (UV-rGO), polymer matrix (polystyrene), and a conjugated composite based on them. The mesoscopic structure of the composites synthesized in this work was studied by such methods as X-ray diffraction, SEM, as well as NMR-, IR- and Raman spectroscopy. The magnetization of the composites under investigation and their components was measured using a vibrating-sample magnetometer. It has been shown that the UV-reduction process leads to the formation of many submicron holes distributed inside rGO flakes, which can create edge defects, causing possibly magnetic order in the graphite samples under investigation on the mesoscopic level. This article provides an alternative explanation for the ferromagnetic hysteresis loop in UV-rGO on the base of superconductivity type-II.

scholarly journals A Facile and Green Synthesis of a MoO2-Reduced Graphene Oxide Aerogel for Energy Storage Devices

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 594 ◽  
Author(s):  
Mara Serrapede ◽  
Marco Fontana ◽  
Arnaud Gigot ◽  
Marco Armandi ◽  
Glenda Biasotto ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Chemical Reduction ◽  
Low Cost ◽  
Xps Analysis ◽  
3D Scaffold ◽  
Energy Storage Devices ◽  
Reduced Graphene

A simple, low cost, and “green” method of hydrothermal synthesis, based on the addition of l-ascorbic acid (l-AA) as a reducing agent, is presented in order to obtain reduced graphene oxide (rGO) and hybrid rGO-MoO2 aerogels for the fabrication of supercapacitors. The resulting high degree of chemical reduction of graphene oxide (GO), confirmed by X-Ray Photoelectron Spectroscopy (XPS) analysis, is shown to produce a better electrical double layer (EDL) capacitance, as shown by cyclic voltammetric (CV) measurements. Moreover, a good reduction yield of the carbonaceous 3D-scaffold seems to be achievable even when the precursor of molybdenum oxide is added to the pristine slurry in order to get the hybrid rGO-MoO2 compound. The pseudocapacitance contribution from the resulting embedded MoO2 microstructures, was then studied by means of CV and electrochemical impedance spectroscopy (EIS). The oxidation state of the molybdenum in the MoO2 particles embedded in the rGO aerogel was deeply studied by means of XPS analysis and valuable information on the electrochemical behavior, according to the involved redox reactions, was obtained. Finally, the increased stability of the aerogels prepared with l-AA, after charge-discharge cycling, was demonstrated and confirmed by means of Field Emission Scanning Electron Microscopy (FESEM) characterization.

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.

The Addition of Reduced Graphene Oxide Layer to TiO2 Photoanode of DSSC Using UV Oven Spraying Method

2020 ◽  
Vol 860 ◽  
pp. 15-21
Author(s):  
Lusi Safriani ◽  
Annisa Aprilia ◽  
Sri Suryaningsih ◽  
Fitri Yuliasari ◽  
Muhammad Rizki Nurawan ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Short Circuit ◽  
Dye Sensitized Solar Cells ◽  
Reduction Process ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Reduced Graphene ◽  
Sensitized Solar Cells ◽  
Spraying Method

The third generation of photovoltaic, called as dye-sensitized solar cells (DSSC) have attracted much attention and currently become an interesting research topics. One important part of DSSC that determines its performance is photoanodes. Recently, graphene has been used to enhance the efficiency of DSSC through the increasing of electronic transportation. Introduction of graphene into DSSC is realized by changing the form of graphene oxide (GO) into reduced graphene oxide (rGO) through the reduction process. In this work, DSSC based on TiO2 photoanodes modified by rGO were fabricated. rGO layer was deposited on TiO2 mesoporous layer using UV-oven spraying method. We found that parameters of DSSC such as open circuit voltage, short circuit current and fill factor increase with the incorporation of rGO layer in TiO2photoanodes. DSSC with TiO2/rGO photoanodes has the highest power conversion efficiency of 11.01% which contributed from the enhancement of short circuit current. The rGO layer found to be an effective layer to block charge recombination in photoanode.

scholarly journals Synthesis and Characterization of Reduced Graphene Oxide (rGO) Started from Graphene Oxide (GO) Using the Tour Method with Different Parameters

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Adere Tarekegne Habte ◽  
Delele Worku Ayele
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Potassium Permanganate ◽  
Chemical Reduction ◽  
Volume Ratio ◽  
Graphite Powder ◽  
Green Approach ◽  
Synthesis Strategy ◽  
Reduced Graphene ◽  
Diffraction Patterns

A new approach to synthesize graphene is oxidizing graphite powder with a mixture of H2SO4/H3PO4 acids and potassium permanganate. Parameters such as reaction time, reaction temperature, and amount of concentration were varied to study the degree of oxidation of graphite to graphene oxide. Currently, an improved method for the preparation of graphene oxide was the most common one. A mixture of H2SO4/H3PO4 (9 : 1 volume ratio) instead of only H2SO4 resulted in increased hydrophilic and oxidized GO without the emission of toxic gas, which differs from the traditional Hummers’ method. The graphene oxide (GO) was converted to reduced graphene oxide (rGO) by chemical reduction using ascorbic acid as the reducing agent. The GO and rGO were characterized by UV-visible spectroscopy, FTIR spectroscopy, and X-ray diffraction patterns. The result showed that treating graphite powder with potassium permanganate (1 : 9) and a mixture of concentrated H2SO4/H3PO4 acids at 50°C for 12 hours resulted in a better oxidation degree. The designed synthesis strategy could be easily controlled and is an alternative green approach for the production of graphene oxide and reduced graphene oxide.

Rh/Ni wet-impregnated Ia3d mesostructured aluminosilicate and r-GO catalysts for hydrodeoxygenation of phenoxybenzene

2017 ◽  
Vol 41 (16) ◽  
pp. 7893-7907 ◽  
Author(s):  
Sudhakar Pichaikaran ◽  
Arumugam Pandurangan
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Surface Area ◽  
Structural Properties ◽  
Bet Surface Area ◽  
Xps Analysis ◽  
Icp Oes ◽  
Reduced Graphene ◽  
Ft Ir

Rh/Ni bimetallic supported bifunctional 3D porous aluminosilicate and Rh/Ni supported reduced graphene oxide (r-GO) catalysts were synthesised and their structural properties evaluated by XRD, BET-surface area, FT-IR, NH3-TPD, H2-TPR, ICP-OES, HRTEM-EDAX and XPS analysis.

One-Step Hydrothermal Reduction and Functionalization of Graphene Oxide with a Modified Diethylene Triamine

2017 ◽  
Vol 1142 ◽  
pp. 225-229
Author(s):  
Yong Ling Pan ◽  
Chuan Guo Ma ◽  
Hua Mei Wan ◽  
De Shui Huang ◽  
Jin Xing Wang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Sedimentation Stability ◽  
Reduction Time ◽  
Diethylene Triamine ◽  
Reduced Graphene ◽  
One Step ◽  
Ft Ir ◽  
Amine Curing Agent ◽  
Conductive Property ◽  
Amine Curing

Graphene oxide (GO) was prepared by modified Hummer’s method, and reduced by solvothermal method using ethanol as the solvent and modified diethylene triamine (amine curing agent 593) as reducing agent and modifier. The effect of reduction time and temperature on the structure and conductive property of reduced graphene oxide (593-rGO) was investigated by SEM, FT-IR and XRD. The results show that the graphene modified by 593 is obviously improved in dispersibility and sedimentation stability in dichloromethane, as well as in conductivity. The optimal reduction processing is that the mass ratio of GO to 593 is 2:1, the reduction time and temperature is 6 h and 160°C, respectively.

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