X-Ray Diffraction Evaluation of the Average Number of Layers in Thermal Reduced Graphene Powder for Supercapacitor Nanomaterial

2019 ◽  
Vol 958 ◽  
pp. 117-122 ◽  
Author(s):  
Quezia de Aguiar Cardoso ◽  
Julio César Serafim Casini ◽  
Luzinete Pereira Barbosa ◽  
Marilene Morelli Serna ◽  
Eguiberto Galego ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Thermal Treatment ◽  
Low Cost ◽  
Reduction Process ◽  
Thermal Reduction ◽  
Processing Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Graphene Layers ◽  
Number Of Layers

Graphene oxide (GO) can be partially reduced to graphene-like sheets by removing the oxygen-containing groups and recovering the conjugated structure. In this work, the thermal reduction of GO powder has been carried out using back pumping vacuum pressures and investigated employing X-ray diffraction analysis. The experimental results of estimating the number of graphene layers on the reduced powder at various temperatures (200 – 1000 °C) have been reported. Electrical changes have been produced in a graphene oxide with the vacuum reduction process. This study has shown that the ideal processing temperature for reducing graphene oxide nanomaterial was about 400 °C. It has also been shown that at 600 °C the number of layers in the reduced nanomaterial increased. The internal series equivalent resistance (ESR) has been improved substantially with the vacuum thermal treatment even at temperatures above 400 °C. ESR was reduced from 95.0 to about 13.8 Ω cm2 with this processing. These results showed that the process can be applied to the reduction of graphene oxide to produce supercapacitor nanomaterials. The advantage of employing this method is that the processing is a straightforward and low cost thermal treatment that might be used for large amount of nanocomposite material.

Study of Interlayer Spacing Collapse During Polymer/Clay Nanocomposite Melt Intercalation

2008 ◽  
Vol 8 (4) ◽  
pp. 1707-1713
Author(s):  
Samira Benali ◽  
Sophie Peeterbroeck ◽  
Jérôme Larrieu ◽  
Fabrice Laffineur ◽  
Jean-Jacques Pireaux ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Vinyl Acetate ◽  
Ethylene Vinyl Acetate ◽  
Interlayer Spacing ◽  
Nano Composites ◽  
Processing Temperature ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Melt Intercalation

The influence of the chemical structure of alkylammonium organo-modifying montmorillonite clays on the ability to form nanocomposites by melt blending, depending on the processing temperature and the organoclay thermal treatment, has been investigated. On one side chlorinated polyethylene/Cloisite®30B (nano)composite has been prepared by melt intercalation at 175 °C and its wide angle X-ray diffraction pattern revealed that the peak characteristic of the interlayer spacing of the organoclay was shifted to lower d-spacing, indicating a collapse of the organoclay structure. On the other side, (nano)composites based on ethylene-vinyl acetate copolymer/Cloisite®30B have been prepared by melt intercalation at 140 °C. At this temperature, exfoliation was observed with the as-received organoclay while the same organo-modified clay, simply dried at 180 °C for 2 hours, induced again the formation of a composite with a collapsed structure. The effect of the Cloisite®30B thermal treatment on the morphology and mechanical properties of ethylene-vinyl acetate–based (nano)composites was investigated using wide angle X-ray diffraction and tensile tests. In order to shed some light on the origin of this clay interlayer collapse, organoclay modified with various ammonium cations bearing long alkyl chains with different amounts of unsaturations were studied using wide angle X-ray diffraction and X-ray photoelectron spectroscopy before and after thermal treatment at 180 °C for 2 hours. Isothermal thermogravimetric analysis of all organoclays was also investigated. The layers collapse effect is discussed depending upon the level of unsatured hydrocarbon present in the organic surfactant.

Synthesis and Characterization of Iron Produced from Iron Mill Scale

2013 ◽  
Vol 594-595 ◽  
pp. 118-122
Author(s):  
Mohd Zaki Ruhiyuddin ◽  
D. Murizam ◽  
Khairel Rafezi Ahmad
Keyword(s):  
Iron Powder ◽  
Heating Temperature ◽  
Low Cost ◽  
Reduction Process ◽  
X Ray Diffraction ◽  
Mill Scale ◽  
X Ray ◽  
Powder Metallurgy Process ◽  
Effective Particle ◽  
Maximum Heating Temperature

In this project, iron mill scale has been used to produce iron powder that can be used within the Powder Metallurgy process. To achieve this objective, the iron mill scale needs to be refined. This involve the work of grinding the iron mill scale to an effective particle size, which is 300μm. Latter, the grounded iron mill scale will undergo the magnetic separation process. The purpose of this process is to remove any non-magnetic material. Than the following process is to fully oxidize and reduce the iron mill scale to form pure iron powder. From this step an optimum value for maximum heating temperature, heating rate and heating cycle was determined. Than in order to determine whether the oxidation and the reduction process have completely achieved their objective, the iron oxide and the iron powder that have been produced from both process, was characterized using X-Ray Diffraction Analysis (XRD) and X-Ray Florescent Analysis (XRF) technique. From the oxidation process, it is obvious that sample C gave higher oxidation percentage, which is 11.22%. While Reduction 2 shows the desirable result, which is 29.51% of reduction, involving a low cost compared to other reduction process.

scholarly journals The approximation of X-ray diffraction profiles of thermally reduced nanostructured derivatives of graphene oxide

2020 ◽  
pp. 17-26
Author(s):  
Н.С. САЕНКО ◽  
А.М. ЗИАТДИНОВ
Keyword(s):  
Graphene Oxide ◽  
Probability Density Function ◽  
Probability Density ◽  
Polar Angle ◽  
Relative Content ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Number Of Layers ◽  
Derivatives Of

В работе представлен метод моделирования рентгеновских дифрактограмм пленок термически восстановленных наноструктурированных производных оксида графена с помощью линейной комбинации теоретических профилей порошков квазидвумерно-разориентированных несколькослойных турбостратных нанографенов (нанографитов). Метод позволяет определять относительное содержание нанографитов с различными средними размерами и числом слоев, а также функцию плотности вероятности, характеризующую долю частиц в порошке повернутых на заданный полярный угол. Предложенная процедура моделирования пригодна также для аппроксимации экспериментальных рентгенограмм любых материалов, содержащих протяженные квазидвумерно-разориентированные структуры турбостратных нанографитов. The paper outlines the procedure of modeling X-ray diffractogram of films for thermally reduced nanostructured graphene oxide derivatives using a linear combination of the theoretical profiles for powders of quasi-two-dimensional misoriented few-layer turbostratic nanographenes (nanographites). The method allows us to determine the relative content of nanographites with various average sizes and number of layers, as well as a probability density function characterizing the fraction of particles in the powder, which is rotated by a certain polar angle. The proposed modeling procedure is also suitable for the approximation of experimental X-ray diffractograms of any materials containing extended quasi-two-dimensional misoriented structures of turbostratic nanographites.

Squeezing out and Characterization of Silicon from Sand by Mg-Thermite Reduction Process

2020 ◽  
Vol 12 ◽  
Author(s):  
Md. Shoriful Islam ◽  
M. A. Sattar ◽  
M. A. Halim ◽  
Md. Asadul Hoque ◽  
Abdul Quader ◽  
...  
Keyword(s):  
Particle Size ◽  
Silicon Content ◽  
Chemical Nature ◽  
Low Cost ◽  
Reduction Process ◽  
Environmentally Benign ◽  
X Ray Diffraction ◽  
X Ray ◽  
Padma River

Background: Sand is one of the efficient sources of Silicon. We get quite easily the plethora of sand from the river side, Bangladesh. Utilization of the superfluous sand can be assisted to enhance our economy. Methods: In this work, silicon is extracted from sand by metal–thermite reduction process and the sample of sand is collected from padma river Rajshahi, Bangladesh. The process is environmentally benign and low cost. The reduction of the sand was performed with Mg powder, and purification was done by leaching out with HCl and HF. We have studied the structural properties, chemical nature and physical morphology. Results and conclusion: X-ray Diffraction (XRD) confirmed that the presence of elemental Si in the samples produced by Mg-thermite reduction process and the particle size was found 25.72±1.3 nm in an average. Surface morphology has been studied using Scanning Electron Microscopy (SEM) and the particle size seemed around 30 to 40 nm which was comparable to the obtained particle size from XRD. Fourier transform infrared spectroscopy (FTIR) showed the presence of Si-Si bonding in the investigating materials. The chemical nature of the sand has been studied by X-ray Fluorescence (XRF) analysis. Silicon content of sand was found about maximum 80%.

scholarly journals Green Solid-State Chemical Reduction of Graphene Oxide Supported on a Paper Substrate

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 693
Author(s):  
Angela Longo ◽  
Mariano Palomba ◽  
Gianfranco Carotenuto
Keyword(s):  
Graphene Oxide ◽  
Solid State ◽  
Chemical Reduction ◽  
Low Cost ◽  
Reduction Process ◽  
Thermal Reduction ◽  
Conversion Degree ◽  
Reduction Techniques ◽  
Reduction Methods ◽  
State Chemical

The reduction of graphene oxide (GO) thin films deposited on substrates is crucial to achieve a technologically useful supported graphene material. However, the well-known thermal reduction process cannot be used with thermally unstable substrates (e.g., plastics and paper), in addition photo-reduction methods are expensive and only capable of reducing the external surface. Therefore, solid-state chemical reduction techniques could become a convenient approach for the full thickness reduction of the GO layers supported on thermally unstable substrates. Here, a novel experimental procedure for quantitative reduction of GO films on paper by a green and low-cost chemical reductant (L-ascorbic acid, L-aa) is proposed. The possibility to have an effective mass transport of the reductant inside the swelled GO solid (gel-phase) deposit was ensured by spraying a reductant solution on the GO film and allowing it to reflux in a closed microenvironment at 50 °C. The GO conversion degree to reduced graphene oxide (r-GO) was evaluated by Fourier transform infrared spectroscopy (FT-IR) in attenuated total reflectance (ATR) mode and X-ray Diffraction (XRD). In addition, morphology and wettability of GO deposits, before and after reduction, were confirmed by digital USB microscopy, scanning electron microscopy (SEM), and contact angle measurements. According to these structural characterizations, the proposed method allows a bulky reduction of the coating but leaves to a GO layer at the interface, that is essential for a good coating-substrate adhesion and this special characteristic is useful for industrial exploitation of the material.

scholarly journals ELECTROCHEMICAL DISPERSION OF GRAPHITE IN 58% NITRIC ACID TO PRODUCE MULTILAYER GRAPHENE OXIDE

2021 ◽  
Vol 64 (3) ◽  
pp. 59-65
Author(s):  
Elena V. Yakovleva ◽  
Andrey V. Yakovlev ◽  
Ivan N. Frolov ◽  
Anton S. Mostovoy ◽  
Vitaly N. Tseluikin
Keyword(s):  
Graphene Oxide ◽  
Graphite Powder ◽  
Multilayer Graphene ◽  
X Ray Diffraction ◽  
X Ray ◽  
Graphene Layers ◽  
Intercalated Compounds ◽  
Fold Reduction ◽  
Electrochemical Dispersion ◽  
Oxidized Graphite

Electrochemical oxidation of graphite powder in 58% HNO3 was studied. Samples of oxidized graphite were obtained with a imparting of the amount of electricity 500, 700, 1500 mAh g-1. The character of the galvanostatic dependencies allows to select a region of the formation of intercalated compounds of graphite prior to the accumulation of quantity of electricity of 500 mA h g-1. It was found that when the quantity of electricity of over 700 mA h g-1 the process of electrochemical peroxidation of intercalated graphite begins with the formation of multilayer graphene oxide, as confirmed by comprehensive studies using X-ray diffraction, scanning electron microscopy, FTIR spectroscopy, laser diffraction. The synthesized multilayer graphene oxide is characterized by the presence of a spectrum of oxygen-containing functional groups, mainly hydroxyl, as well as carboxyl, epoxy and alkoxyl. X-ray images show a peak at 2θ = 11.45° which intensity increases for re-oxidized graphite compounds and also indicate the formation of a multilayer graphene oxide with an interlayer distance of 7.8 Å. The synthesized material in aqueous suspensions under the action of ultrasound is dispersed with a 7-11-fold reduction in particle size. Graphene layers remains layered structure but the degree of their deformation increases, and the thickness of the layers decreases with an increase in the imparted amount of electricity. 

Low-Temperature Reduction of Graphene Oxide Using the HDDR Process for Electrochemical Supercapacitor Applications

2020 ◽  
Vol 1012 ◽  
pp. 141-146
Author(s):  
F.G. Benitez Jara ◽  
P. D. V. Cruz ◽  
Lusinete Pereira Barbosa ◽  
J.C.S. Casini ◽  
S. K. Sakata ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Low Temperature ◽  
Large Scale ◽  
Oxide Powder ◽  
Processing Temperature ◽  
Scale Production ◽  
X Ray Diffraction ◽  
Promising Alternative ◽  
X Ray ◽  
Large Scale Production

In the present work, attempts of reducing a graphene oxide powder using a low temperature hydrogenation disproportionation desorption and the recombination process (L-HDDR) has been carried out. A lower processing temperature in large scale production is significant when costs are concerned. Graphite oxide was prepared using a modified Hummers’ method dispersed in ethanol and exfoliated using ultrasonication to produce Graphene Oxide (GO). Investigations have been carried out by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The experimental results of L-HDDR processing graphene oxide powder, using unmixed hydrogen at 400°C and relatively low pressures (<2 bars) have been reported. X-ray diffraction patterns showed a reduction of graphene oxide with the L-HDDR process. The results showed that both processes, the L-HDDR as well as the standard HDDR, may be applied to the reduction of graphene oxide in order to produce supercapacitor materials. The advantage of employing the L-HDDR process is a relatively low temperature reducing the cost of treatment, what is a very important factor for producing a large amount of material. Thus, the L-HDDR process has been considered a promising alternative method of reducing graphene oxide with efficiency, with the possibility of large scale production.

scholarly journals Performance Enhancement of Modified 3D SWCNT/RVC Electrodes Using Microwave-Irradiated Graphene Oxide

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Ali Aldalbahi ◽  
Mostafizur Rahaman ◽  
Mohammed Almoiqli
Keyword(s):  
Graphene Oxide ◽  
Structural Changes ◽  
Performance Enhancement ◽  
Photoelectron Spectra ◽  
Composite Electrodes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Graphene Layers ◽  
Electrode Surfaces ◽  
Porous Architecture

Abstract The goal of this article is to increase the electrode performance of 3D CNT/RVC electrodes by improving the ease of ion adsorption to and ion desorption from the electrode surfaces. This achievement was done by preparing different composites of synthesized microwave-irradiated graphene oxide (mwGO) with CNT and coated on RVC. The morphology of GO was examined by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) study. Its surface property was checked by energy-dispersive X-ray spectra (EDX), and Fourier transform infrared spectra; whereas, for mwGO by XRD, Raman spectra, and X-ray photoelectron spectra (XPS), which revealed some structural changes of GO after irradiation, where CNTs, being sandwiched between graphene layers, built 3D highly porous architecture inside the electrodes. The electrochemical test of composite electrodes showed increased electrodes conductivity and afforded rapid ions diffusion. It is observed that the 9-CNT/mwGO/RVC composite electrode performed as the best electrode, which showed 29% increment in specific capacitance value compared to the normal CNT/RVC electrode. This best electrode also showed very high cyclic stability in its cyclic voltammetry test that maintained 97% current stability after 2000 cycles, indicating that the electrode can be an effective material for water purification technology. Graphical Abstract

scholarly journals Exploration of the temperature-dependent correlations present in the structural, morphological and electrical properties of thermally reduced free-standing graphene oxide papers

2021 ◽  
Author(s):  
Harihara Ramamoorthy ◽  
Kanokwan Buapan ◽  
Tinna Chiawchan ◽  
Krongtham Thamkrongart ◽  
Ratchanok Somphonsane
Keyword(s):  
Graphene Oxide ◽  
Structural Changes ◽  
Morphological Changes ◽  
Reduction Process ◽  
Thermal Reduction ◽  
X Ray Diffraction ◽  
Free Standing ◽  
Force Microscopy ◽  
Atomic Force ◽  
Current Voltage

AbstractWe report on a corroborative study of the structural, morphological and electrical property alterations of free-standing graphene oxide (GO) papers subject to thermal reduction. Structural analysis performed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Raman techniques prove that the onset of major structural changes, characterized by removal of oxygen functionalities, occur in the 200–300 °C temperature range. The results are corroborated with related morphological changes observed using Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) imaging. Elemental analysis shows the GO paper reduced at 600 °C to contain an 85 wt. % carbon content and a remnant oxygen level of 13.31 wt. %. At the highest reduction temperatures, we see evidence of vacancy-type defects impeding the overall effectiveness of the reduction process. Detailed electrical resistance measurements and current–voltage (I-V) profiling conducted using four-point probe method reveals a several orders of magnitude drop in the sample resistance once the reduction temperature exceeds 200 °C, in good agreement with the structural and morphological changes. The fundamental insights revealed through these studies will be important for future applications where the electrical and mechanical properties of free-standing GO and reduced graphene oxide (rGO) are exploited in practical devices. Graphical abstract

Effect of synthesis and activation methods on the character of CoMo/ultrastable Y-zeolite catalysts

2021 ◽  
Vol 19 (1) ◽  
pp. 745-754
Author(s):  
Khoirina Dwi Nugrahaningtyas ◽  
Eddy Heraldy ◽  
Rachmadani ◽  
Yuniawan Hidayat ◽  
Indriana Kartini
Keyword(s):  
Electron Microscopy ◽  
Reduction Process ◽  
Particle Morphology ◽  
Zeolite Catalysts ◽  
X Ray Diffraction ◽  
Y Zeolite ◽  
X Ray ◽  
Irregular Particle ◽  
Transmission Electron ◽  
Pure Metals

Abstract The properties of three types of CoMo/USY catalysts with different synthesized methods have been studied. The sequential and co-impregnation methods followed by activation using calcination and reduction process have been conducted. The properties of the catalysts were examined using Fourier-transform-infrared (FTIR) spectroscopy, X-ray diffraction (XRD) with refinement, and surface area analyzer (SAA). The FTIR spectrum study revealed the enhanced intensity of its Bronsted acid site, and the XRD diffractogram pattern verified the composition of pure metals, oxides, and alloys in the catalyst. The SAA demonstrated the mesoporous features of the catalyst. Scanning electron microscopy showed an irregular particle morphology. Additional analysis using the transmission electron microscopy indicated that the metal has successfully impregnated without damaging the USY structure.

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