A Facile and Efficient Method to Prepare Exfoliated and Reduced Graphene Nanosheets by Detonation

2014 ◽  
Vol 937 ◽  
pp. 260-266 ◽  
Author(s):  
Yan Hua Guo ◽  
Dong Xian Zhuo ◽  
Li Xin Wu ◽  
Lin Ma ◽  
Zi Xiang Weng ◽  
...  
Keyword(s):  
Specific Surface ◽  
Graphene Nanosheets ◽  
Low Cost ◽  
High Specific Surface Area ◽  
X Ray Diffraction ◽  
Atomic Force ◽  
Transmission Electron ◽  
Composition And Structure ◽  
Reduced Graphene ◽  
Detonation Method

A facile, efficient, and low energy consumption detonation method to prepare few-layered graphene nanosheets has been developed using graphite oxide as a precursor at detonation induced temperature as low as 100 °C . The composition and structure of as-produced few-layered graphenes were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR), Specific Surface (BET), Transmission Electron Microscopy (TEM), Raman Microscope, and Atomic Force Microscope (AFM). Results showed that the as-produced graphenes were transparent and few-layered with a high specific surface area (225.9 m2/g). The investigation opens a new road to prepare few-layered graphene nanosheets at low exfoliation temperature in a low-cost and facile way.

Synthesis of Graphene Nanosheets via Thermal Exfoliation of Pretreated Graphite at Low Temperature

2010 ◽  
Vol 123-125 ◽  
pp. 787-790 ◽  
Author(s):  
Long Yue Meng ◽  
Soo Jin Park
Keyword(s):  
Low Temperature ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Graphene Nanosheets ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Pre Treatment

In this work, we synthesized graphene nanosheets via a soft chemistry synthetic route involving pre-exfoliation treatment, strong oxidation, and post thermal exfoliation. X-ray diffraction (XRD), Raman spectroscopy, atomic force microscopy (AFM), and transmission electron microscopy (TEM) confirmed the ordered graphite crystal structure and morphology of graphene nanosheets. N2 adsorption was used to determine the specific surface area of graphene nanosheets. As a result, pre-treatment of the graphite with HNO3/H2SO4 mixture produced the exfoliated graphite nanoplates, and the post thermal exfoliation of the graphite oxide nanosheets at low temperature led to produce a large number graphene nanosheets. The specific surface area of obtained graphene nanosheets was 333 m2/g.

Detonation Synthesis of TiO2 Nanoparticles in Gas Phase

2008 ◽  
Vol 32 ◽  
pp. 13-16 ◽  
Author(s):  
X.J. Li ◽  
Xin Ouyang ◽  
Hong Hao Yan ◽  
G.L. Sun ◽  
F. Mo
Keyword(s):  
Specific Surface ◽  
Gas Phase ◽  
Surface Area ◽  
Specific Surface Area ◽  
Measurement Data ◽  
High Specific Surface Area ◽  
Detonation Synthesis ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Detonation Method

In this paper, TiO2 nanopowders are produced by gas-phase detonation method. The powders are analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and specific surface area determination. The results indicate that the powders are mixed crystal of rutile and anatase, and have good dispersibility and high specific surface area. Also, the particle sizes of powders are between 40 to 200 nm which are spheroid and cube. The measurement data of detonation pressures shows that the reaction took place under a deflagration to detonation transition (DDT).

Synthesis and Characterization of Porous Mo-W Oxide Nanostructures

2008 ◽  
Vol 8 (12) ◽  
pp. 6445-6450
Author(s):  
F. Paraguay-Delgado ◽  
Y. Verde ◽  
E. Cizniega ◽  
J. A. Lumbreras ◽  
G. Alonso-Nuñez
Keyword(s):  
Electron Microscopy ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Synthesis Method ◽  
Atomic Ratio ◽  
High Specific Surface Area ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Before And After

The present study reports the synthesis method, microstructure characterization, and thermal stability of nanostructured porous mixed oxide (MoO3-WO3) at 550 and 900 °C of annealing. The material was synthesized using a hydrothermal method. The precursor was prepared by aqueous solution using ammonium heptamolibdate and ammonium metatungstate, with an atomic ratio of Mo/W = 1. The pH was adjusted to 5, and then the solution was transferred to a teflon-lined stainless steel autoclave and heated at 200 °C for 48 h. The resultant material was washed using deionized water. The specific surface area, morphology, composition, and microstructure before and after annealing were studied by N2 physisorption, scanning electron microscopy (SEM), analytical transmission electron microscopy (TEM), and X-Ray diffraction (XRD). The initial synthesized materials showed low crystallinity and high specific surface area around (141 m2/g). After thermal annealing the material showed higher crystallinity and diminished its specific surface area drastically.

scholarly journals Graphene Synthesis by Ultrasound Energy Assisted Exfoliation of Graphite in Various Solvents

2020 ◽  
Author(s):  
Betül Gürünlü ◽  
Çiğdem Taşdelen-Yücedağ ◽  
Mahmut Bayramoğlu
Keyword(s):  
Low Cost ◽  
Dimethyl Formamide ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Graphene Synthesis ◽  
Atomic Force ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Ultrasound Energy ◽  
Size And Morphology

Liquid Phase Exfoliation (LPE) method has been gaining increasing interest by academic and industrial researchers due to its simplicity, low-cost, and scalability. High intensity ultrasound energy was exploited to transform graphite to graphene in the solvents of dimethyl sulfoxide (DMSO), N,N-dimethyl formamide (DMF), and perchloric acid (PA) without any surfactants or ionic liquids. The crystal structure, number of layers, particle size, and morphology of the synthesized graphene samples were characterized by X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), Ultraviolet visible (UV–vis) spectroscopy, Dynamic Light Scattering (DLS), and Transmission Electron Microscopy (TEM). XRD and AFM analyses indicated that G-DMSO and G-DMF have few layers and G-PA has multilayers. The layer numbers of G-DMSO, G-DMF, and G-PA were determined as 9, 10, and 21, respectively. By DLS analysis, the particle sizes of graphene samples were estimated in a few micrometers. TEM analyses showed that G-DMSO and G-DMF possess sheet-like fewer layers and also, G-PA has wrinkled and unordered multilayers.

scholarly journals rGO Sheets / ZnFe2O4 Nanocomposities as an Efficient Electro Catalyst Material for I3- / I- Reaction for High Performance DSSCs

2021 ◽  
Author(s):  
Anto feradrick Samson V ◽  
Bharathi Bernadsha S ◽  
Albin John P Paul Winston ◽  
Divya D ◽  
James Abraham ◽  
...  
Keyword(s):  
High Performance ◽  
Electrochemical Impedance ◽  
Low Cost ◽  
Dye Sensitized Solar Cells ◽  
X Ray Diffraction ◽  
Tafel Polarization ◽  
Highly Active ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Sensitized Solar Cells

Abstract In this paper, Reduced Graphene Oxide (rGO) / ZnFe2O4 (rZnF) nanocomposite is synthesized by a simple hydrothermal method and employed as a counter electrode (CE) material for tri-iodide redox reactions in Dye sensitized solar cells (DSSC) to replace the traditional high cost platinum (Pt) CE. X-ray diffraction analysis (XRD) and High resolution Transmission electron microscopy (HR-TEM), clearly indicated the formation of rZnF nanocomposite and also amorphous rGO sheets were smoothly distributed on the surface of ZnFe2O4 (ZnF) nanostructure. The rZnF-50 CE shows excellent electro catalytic activity toward I3− reduction, which has simultaneously been confirmed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Tafel polarization measurements. A DSSC developed by rZnF-50 CE (η = 8.71%) obtained quite higher than the Pt (η = 8.53%) based CE under the same condition. The superior performances of rZnF-50 CE due to addition of graphene in to Spinel (ZnF) nanostructure results in creation of highly active electrochemical sites, fast electron transport linkage between CE and electrolyte. Thus it’s a promising low cost CE material for DSSCs.

Synthesis of AnataseTiO2 Having High Specific Surface Area from a Gel Precursor

2011 ◽  
Vol 485 ◽  
pp. 279-282
Author(s):  
Keiko Fukushi ◽  
Sae Nakajima ◽  
Kazuyoshi Uematsu ◽  
Tadashi Ishigaki ◽  
Kenji Toda ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Temperature Stability ◽  
High Specific Surface Area ◽  
High Temperature Stability ◽  
X Ray Diffraction ◽  
Dialysis Treatment ◽  
X Ray ◽  
Transmission Electron

Anatase TiO2 having high temperature stability and specific surface area was synthesized using a gel precursor in very mild conditions. The precursor gel was obtained by dialysis treatment of Na16Ti10O28–HNO3 solution. The samples were characterized by X-ray diffraction analysis, transmission electron microscopy, Brunner–Emmett–Teller method for specific surface area measurements, and thermogravimetric analysis.

Hydrothermal Synthesis of Porous Graphene Nanosheets for Supercapacitors

2015 ◽  
Vol 719-720 ◽  
pp. 119-122
Author(s):  
Zi Long Liu ◽  
Fu Jun Xia ◽  
Qing Zhong Xue ◽  
Yong Gang Du ◽  
Qi Kai Guo
Keyword(s):  
High Current Density ◽  
Graphene Nanosheets ◽  
Low Cost ◽  
Pristine Graphene ◽  
High Current ◽  
Supercapacitor Electrode ◽  
Porous Graphene ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Novel Strategy

Porous graphene has been easily synthesized by hydrothermal treating reduced graphene oxide in alkaline solution, and the porous structure was confirmed by transmission electron microscope. When used as supercapacitor electrode, porous graphene holds a specific capacitance of 88 F g-1 at an ultra-high current density of 50 A g-1, an increase of about 83% compared with that for the pristine graphene sheets. The results demonstrate that porous graphene opens a new and short way for ion transportation. Furthermore our findings provide a novel strategy to fabricate porous graphene and the process is simple, low-cost and environmentally friendly.

scholarly journals Graphene Synthesis by Ultrasound Energy-Assisted Exfoliation of Graphite in Various Solvents

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1037
Author(s):  
Betül Gürünlü ◽  
Çiğdem Taşdelen-Yücedağ ◽  
Mahmut Bayramoğlu
Keyword(s):  
Low Cost ◽  
Dimethyl Formamide ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Graphene Synthesis ◽  
Atomic Force ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Ultrasound Energy ◽  
Size And Morphology

The liquid-phase exfoliation (LPE) method has been gaining increasing interest by academic and industrial researchers due to its simplicity, low cost, and scalability. High-intensity ultrasound energy was exploited to transform graphite to graphene in the solvents of dimethyl sulfoxide (DMSO), N,N-dimethyl formamide (DMF), and perchloric acid (PA) without adding any surfactants or ionic liquids. The crystal structure, number of layers, particle size, and morphology of the synthesized graphene samples were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), ultraviolet visible (UV–vis) spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM). XRD and AFM analyses indicated that G-DMSO and G-DMF have few layers while G-PA has multilayers. The layer numbers of G-DMSO, G-DMF, and G-PA were determined as 9, 10, and 21, respectively. By DLS analysis, the particle sizes, polydispersity index (PDI), and zeta potential of graphene samples were estimated in a few micrometers. TEM analyses showed that G-DMSO and G-DMF possess sheet-like fewer layers and also, G-PA has wrinkled and unordered multilayers.

One-step combustion synthesis of NiFe2O4-reduced graphene oxide hybrid materials for photodegradation of methylene blue

2014 ◽  
Vol 07 (01) ◽  
pp. 1350065 ◽  
Author(s):  
Dafeng Zhang ◽  
Qi Ding ◽  
Xipeng Pu ◽  
Changhua Su ◽  
Xin Shao ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Hybrid Materials ◽  
Combustion Method ◽  
High Specific Surface Area ◽  
X Ray Diffraction ◽  
Adsorptive Property ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
One Step

NiFe 2 O 4-reduced graphene oxide (RGO) hybrid materials (NFRGs) were synthesized by a simple one-step combustion method. The structures, morphologies and magnetic properties were characterized by X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and vibrating sample magnetometer analysis. The results show that graphene oxide sheets are not oxidized, but reduced to RGO. The superparamagnetic behavior of NFRGs was observed. The as-synthesized magnetically separable NFRGs show improved photodegradation performance when compared to neat NiFe 2 O 4, attributed to the narrowing band gap, the efficient transfer of photo-generated electron from NiFe 2 O 4 to RGO sheets, and the improved adsorptive property of photocatalyst due to the high specific surface area of RGO sheets.

scholarly journals Nanocomposite of CeO2 and High-Coercivity Magnetic Carrier with Large Specific Surface Area

2016 ◽  
Vol 2016 ◽  
pp. 1-13
Author(s):  
Alice Reznickova Mantlikova ◽  
Jiri Plocek ◽  
Barbara Pacakova ◽  
Simona Kubickova ◽  
Ondrej Vik ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Synthesis Method ◽  
High Specific Surface Area ◽  
High Coercivity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

We succeeded in the preparation of CoFe2O4/CeO2 nanocomposites with very high specific surface area (up to 264 g/m2). First, highly crystalline nanoparticles (NPs) of CoFe2O4 (4.7 nm) were prepared by hydrothermal method in water-alcohol-oleic acid system. The oleate surface coating was subsequently modified by ligand exchange to citrate. Then the NPs were embedded in CeO2 using heterogeneous precipitation from diluted Ce3+ sulphate solution. Dried samples were characterized by Powder X-Ray Diffraction, Energy Dispersive X-Ray Analysis, Scanning and Transmission Electron Microscopy, Mössbauer Spectroscopy, and Brunauer-Emmett-Teller method. Moreover, detailed investigation of magnetic properties of the bare NPs and final composite was carried out. We observed homogeneous embedding of the magnetic NPs into the CeO2 without significant change of their size and magnetic properties. We have thus demonstrated that the proposed synthesis method is suitable for preparation of extremely fine CeO2 nanopowders and their nanocomposites with NPs. The morphology and magnetic nature of the obtained nanocomposites make them a promising candidate for magnetoresponsive catalysis.

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