Optical Characteristics of Multilayer Reduced Graphene Oxides Films Fabricated Using UV Oven Spraying Technique with Various Interval Irradiation Time

2021 ◽  
Vol 1028 ◽  
pp. 279-284
Author(s):  
Nur Khanifah ◽  
Diyan Unmu Dzujah ◽  
Vika Marcelina ◽  
Rahmat Hidayat ◽  
Fitrilawati ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Irradiation Time ◽  
Active Material ◽  
Reduction Process ◽  
Optical Characteristics ◽  
Graphene Oxides ◽  
Super Capacitor ◽  
Reduced Graphene ◽  
Vis Spectroscopy ◽  
Coating Method

Reduced graphene oxide (RGO) is promising candidate to be used as an active material of super capacitor electrodes. Graphene oxide (GO) is mostly used as a precursor, therefore it is needed to remove its oxygen containing functional groups. Generally, the RGO films are obtained from Graphene Oxide (GO) films which are then treated using thermal reduction or photo reduction process. We developed a spraying coating method that called as UV oven spraying by combining spraying coating method and photo reduction process. By this deposition method, we can obtain RGO films directly from the GO precursor since deposition and photo reduction steps are taken place at the same time. Level of oxygen removal of the obtained RGO film depends on irradiation intensity and length of irradiation. In this work, we report the effect of varied length of irradiation time on the RGO optical characteristics. We prepared multilayer of RGO films using UV oven spraying technique on quartz substrates from 0.5 mg/ml commercial GO dispersion (Graphenea) with varied the UV irradiation time. We used 125-Watt mercury lamp that was set at distance of 30 cm from substrates. We examined the effect of varied of length of irradiation time on its optical characteristics using UV-Vis Spectroscopy. Level of reduction by provided irradiation time was examined using SEM/EDS measurement.

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 Structural and Capacitive Properties of Graphene Obtained by a Green Method of Graphene Oxide Reduction

2019 ◽  
Vol 33 (3) ◽  
pp. 385-393
Author(s):  
Matea Raić ◽  
Denis Sačer ◽  
Marijana Kraljić Roković
Keyword(s):  
Graphene Oxide ◽  
Ph Value ◽  
Reduction Process ◽  
Reducing Agent ◽  
Green Method ◽  
Reduced Graphene ◽  
Capacitive Properties ◽  
Vis Spectroscopy ◽  
Reduction Efficiency ◽  
Olive Mill

In this study, a green method was applied in order to reduce graphene oxide (GO).<br /> Reduction was carried out at 80 °C in the presence of phenolic compounds from olive<br /> leaf extract (OLE), and olive mill wastewater (OMW) as a reducing agent. Owning to the<br /> natural origin of the reducing agent, this method is environmentally friendly. Reduction<br /> was carried out at pH=7 and pH=10 in the presence of OLE, and at pH=10 in the presence<br /> of OMW. The reduction process was monitored using UV/Vis spectroscopy. The structural properties of the reduced graphene oxide (rGO) samples were characterized by Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Structural studies demonstrated that a part of the oxygen functionalities in the graphene oxide structure had been removed, which resulted in increased electrical conductivity as proved by the four-point probe method. Better reduction efficiency, as well as better capacitive<br /> properties, were obtained at increased pH value. Capacitive properties of rGO were determined using the cyclic voltammetry technique. The influence of the different reducing agents, OLE and OMW, on rGO capacitive properties is also shown in this work.

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 The Role of Bio-Extracted Reduced Graphene Oxide in the Crystallization Kinetics of Chitosan Bio-Polymer

2021 ◽  
pp. 1-4
Author(s):  
Solomon L Joseph ◽  
◽  
Agumba O John ◽  
Fanuel M Keheze ◽  
◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Carbon Nanomaterials ◽  
High Strength ◽  
Limiting Factor ◽  
Reduced Graphene ◽  
Electrical Conductivities ◽  
Coating Method ◽  
Potential Applications ◽  
New Applications

Carbon nanomaterials have recently attracted wide scientific applications due to their tunable properties. These novel materials act as best fillers that can provide substantial benefits due to their high strength, thermal conductivity, and electrical conductivities. With their huge applications as bulk materials, when implemented in polymer matrix as fillers, they give rise to new promising materials with which their properties can be tuned to suit a particular application. Besides the development of these new nanocomposite materials, there exist some challenges which must be fully surpassed to explore the potentiality of application of carbon-based nanocomposites. Reduced graphene oxide is one of the carbon derivatives which has attracted the current advancement in technology, and recently, it found its new applications in super capacitors used in electronic industries. The limiting factor for its exploration is the affordability. New and affordable sources of these graphene-based nanomaterial have to be devised, for fully realization of their potential applications. In this study, reduced graphene oxide and the bio-polymer chitosan were extracted from the locally available bio waste materials. Nanocomposites were prepared at 50% rGO: chitosan ratio. The films were then prepared by spin coating method. Prepared films were subjected to morphological analysis. From the results, it was observed that rGO induced chitosan crystallization, which led to formation of dendritic structures. Cellulose nanocrystals have thus displayed temperature dependent positive uniaxial birefringence

Nanohybrids of RGO nanosheets and 2-dimensional porous Co3O4 nanoflakes working as highly efficient counter electrodes for dye-sensitized solar cells

2016 ◽  
Vol 4 (43) ◽  
pp. 10323-10328 ◽  
Author(s):  
Feng Du ◽  
Xueqin Zuo ◽  
Qun Yang ◽  
Guang Li ◽  
Zongling Ding ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Solar Cells ◽  
Dye Sensitized Solar Cells ◽  
Reduction Process ◽  
Graphene Oxide Nanosheets ◽  
Counter Electrodes ◽  
Dye Sensitized ◽  
Reduced Graphene ◽  
Sensitized Solar Cells ◽  
Hydrothermal Reduction

In this paper, nanohybrids (Co3O4@RGO) of 2-dimensional (2D) porous Co3O4 nanoflakes anchored on reduced graphene oxide nanosheets have been fabricated by a facile hydrothermal reduction process.

Pristine, Reduced, and Alkylated Graphene Oxide as Additives to Paraffin Grease for Enhancement of Tribological Properties

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Sooraj Singh Rawat ◽  
A. P. Harsha ◽  
O. P. Khatri ◽  
Rolf Wäsche
Keyword(s):  
Graphene Oxide ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Protective Film ◽  
Elemental Mapping ◽  
Graphene Oxides ◽  
Fiber Network ◽  
Maximum Reduction ◽  
Reduced Graphene ◽  
Minimum Resistance

Abstract Pristine, reduced, and alkylated graphene oxides are applied as lubricating additives in paraffin grease. It has revealed that their crystalline structure governs the tribological properties of grease for steel tribo-pair. The microstructural analyses of grease samples showed that a loose fiber network of soap in the presence of graphene-based additive allows their facile release for efficient lubrication. The surface analyses based on the microscopic and elemental mapping show the development of a graphene-derived protective film on the worn scars, which protected the tribo-surfaces and subsided the wear. The reduced graphene oxide (rGO) with the interlamellar distance of 0.35 nm in the (002) plane provided minimum resistance to shear and exhibited maximum reduction in coefficient of friction (COF) for the paraffin grease. The presence of oxygen functionalities in the basal of pristine and alkylated graphene oxide (GO) compromised the interlamellar shearing under tribo-stress; consequently, higher COF than that of rGO.

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.

Synthesis of TiO2-Reduced Graphene Oxide Nanocomposites Offering Highly Enhanced Photocatalytic Activity

2019 ◽  
Vol 19 (11) ◽  
pp. 7089-7096 ◽  
Author(s):  
Wufa Li ◽  
Xiaohong Yang ◽  
Haitao Fu ◽  
Xizhong An ◽  
Haiyang Zhao
Keyword(s):  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Environmental Remediation ◽  
Hydrothermal Reaction ◽  
Photogenerated Electron ◽  
Electron Hole ◽  
Reduced Graphene ◽  
Vis Spectroscopy ◽  
Hole Recombination

Photogenerated electron–hole recombination significantly restricts the catalytic efficiency of titanium dioxide (TiO2). Various approaches have been developed to overcome this problem, yet it remains challenging. Recently, graphene modification of TiO2 has been considered as an effective alternative to prevent electron–hole recombination and consequently enhance the photocatalytic performance of TiO2. This study reports an efficient but simple hydrothermal method utilizing titanium (IV) butoxide (TBT) and graphene oxide (GO) to prepare TiO2-reduced graphene oxide (RGO) nanocomposites under mild reaction conditions. This method possesses several advantageous features, including no requirement of high temperature for TiO2 crystallization and a one-step hydrothermal reaction for mild reduction of GO without a reducing agent, which consequently makes the production of TiO2-RGO nanocomposites possible in a green and an efficient synthetic route. Moreover, the as-synthesized nanocomposites were characterized by numerous advanced techniques (SEM, TEM, BET, XRD, XPS, and UV-vis spectroscopy). In particular, the photocatalytic activities of the synthesized TiO2-RGO nanocomposites were evaluated by degrading the organic molecules (methylene blue, MB), and it was found that the photocatalytic activity of TiO2-RGO nanocomposites is ~4.5 times higher compared to that of pure TiO2. These findings would be useful for designing reduced graphene oxide-metal oxide hybrids with desirable functionalities in various applications for energy storage devices and environmental remediation.

Sign in / Sign up

Export Citation Format

Share Document