Simplified production of graphene oxide assisted by high shear exfoliation of graphite with controlled oxidation

The addition of nanomaterials, such as graphene and graphene oxide, can improve the mechanical properties of hydroxyapatite (HA) nanocomposites (NCPs). However, both the dispersive state of the starting materials and the sintering process play central roles in improving the mechanical properties of the final HA NCPs. Herein, we studied the mechanical properties of a reduced graphene oxide (r-GO)/HA NCP, for which an ultra-high shear force was used to achieve a nano-sized mixture through the dispersion of r-GO. A low-temperature, short-duration spark plasma sintering (SPS) process was used to realize high-density, non-decomposing r-GO/HA NCPs with an improved fracture toughness of 97.8% via the addition of 0.5 wt.% r-GO. Greater quantities of r-GO improve the hardness and the fracture strength. The improved mechanical properties of r-GO/HA NCPs suggest their future applicability in biomedical engineering, including use as sintered bodies in dentistry, plasma spray-coatings for metal surfaces, and materials for 3D printing in orthopedics.

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One-spot synthesis of FeOOH/rGO composites by ferrous-ion-induced self-assembly of graphene oxides with different degrees of oxidation

PLoS ONE ◽

10.1371/journal.pone.0246386 ◽

2021 ◽

Vol 16 (2) ◽

pp. e0246386

Author(s):

Yang Hu ◽

Qingyang Yang ◽

Yingyu Gu

Keyword(s):

Graphene Oxide ◽

Surface Area ◽

Self Assembly ◽

Charge Transfer Resistance ◽

Nano Particles ◽

Ferrous Ion ◽

Spot Synthesis ◽

Graphene Oxides ◽

Transfer Resistance ◽

Oxidized Graphite

In this study, graphene oxide sheets with different oxidation degrees were reduced by ferrous ion for coating FeOOH nano particles on reduced graphene oxide (rGO) matrix to synthesize FeOOH/rGO composites. The effect of the degree of oxidation on the morphology and chemical structure of FeOOH/rGO was studied using scanning electron microscopy, Raman spectroscopy, thermogravimetric analysis, and Brunauer-Emmett-Teller surface area analysis. The particle size of FeOOH crystallites was approximately 100 nm, and they were distributed uniformly on the surface and in the pores of FeOOH/rGO. FeOOH/rGO prepared with mildly oxidized graphite had fewer defects, higher specific surface area, and higher FeOOH content than FeOOH/rGO prepared with highly oxidized graphite. These features resulted in better electrochemical properties, such as larger specific capacitance and lower charge transfer resistance.

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

IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA ◽

10.6060/ivkkt.20216403.6324 ◽

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.

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SYNTHESIS OF GRAPHENE OXIDE USING MILDLY OXIDIZED GRAPHITE THROUGH ULTRASONIC EXFOLIATION

Surface Review and Letters ◽

10.1142/s0218625x17500871 ◽

2016 ◽

Vol 24 (06) ◽

pp. 1750087

Author(s):

YANG HU ◽

ZHUANG LI ◽

HONGQIANG LI ◽

SHAOXIAN SONG ◽

ALEJANDRO LOPEZ-VALDIVIESO

Keyword(s):

Graphene Oxide ◽

Direct Method ◽

Reaction System ◽

X Ray Diffraction ◽

Oxidation Degree ◽

X Ray ◽

Force Microscopy ◽

Atomic Force ◽

Oxidized Graphite ◽

Ultrasonic Homogenizer

This study investigated the preparation of graphene oxide from mildly oxidized graphite through ultrasonic exfoliation. Both the original and produced materials were analyzed by ultraviolet–visible spectrophotometer, X-ray diffraction and atomic force microscopy. The results indicated that the exfoliation yield of graphene oxide was proportional to the input ultrasonic energy. In addition, a two-stage exfoliation phenomenon was observed in the exfoliation of mildly oxidized graphite with both ultrasonic homogenizer and cleaner. It also was found that increasing the content of [[Formula: see text]] in a C–H2SO4–[[Formula: see text]] reaction system was the most simple and direct method to increase the oxidation degree of graphite oxide.

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High apparent strengthening efficiency for reduced graphene oxide in copper matrix composites produced by molecule-lever mixing and high-shear mixing

RSC Advances ◽

10.1039/c5ra04782j ◽

2015 ◽

Vol 5 (63) ◽

pp. 51193-51200 ◽

Cited By ~ 31

Author(s):

Lidong Wang ◽

Ye Cui ◽

Bin Li ◽

Shuai Yang ◽

Ruiyu Li ◽

...

Keyword(s):

Mechanical Properties ◽

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Molecular Level ◽

Copper Matrix ◽

High Shear ◽

Matrix Composites ◽

Reduced Graphene ◽

Shear Mixing ◽

Mixing Method

The RGO sheets are homogeneously distributed in the RGO/Cu composite produced by the molecular-level mixing and high-shear mixing method and the composites with high mechanical properties are obtained.

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