scholarly journals Effects of Buffer Gases on Graphene Flakes Synthesis in Thermal Plasma Process at Atmospheric Pressure

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 309 ◽  
Author(s):  
Cheng Wang ◽  
Ming Song ◽  
Xianhui Chen ◽  
Dongning Li ◽  
Weiluo Xia ◽  
...  
Keyword(s):  
Thermal Plasma ◽  
Atmospheric Pressure ◽  
Spherical Particles ◽  
Plasma Process ◽  
X Ray ◽  
Nitrogen Doped ◽  
Graphene Flakes ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene ◽  
Thermal Plasma Process

A thermal plasma process at atmospheric pressure is an attractive method for continuous synthesis of graphene flakes. In this paper, a magnetically rotating arc plasma system is employed to investigate the effects of buffer gases on graphene flakes synthesis in a thermal plasma process. Carbon nanomaterials are prepared in Ar, He, Ar-H2, and Ar-N2 via propane decomposition, and the product characterization is performed by transmission electron microscopy (TEM), Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and the Brunauer–Emmett–Teller (BET) method. Results show that spherical particles, semi-graphitic particles, and graphene flakes coexist in products under an Ar atmosphere. Under an He atmosphere, all products are graphene flakes. Graphene flakes with fewer layers, higher crystallinity, and a larger BET surface area are prepared in Ar-H2 and Ar-N2. Preliminary analysis reveals that a high-energy environment and abundant H atoms can suppress the formation of curved or closed structures, which leads to the production of graphene flakes with high crystallinity. Furthermore, nitrogen-doped graphene flakes with 1–4 layers are successfully synthesized with the addition of N2, which indicates the thermal plasma process also has great potential for the synthesis of nitrogen-doped graphene flakes due to its continuous manner, cheap raw materials, and adjustable nitrogen-doped content.

Hydrogenation and dehydrogenation of nitrogen-doped graphene investigated by X-ray photoelectron spectroscopy

2015 ◽  
Vol 634 ◽  
pp. 89-94 ◽  
Author(s):  
F. Späth ◽  
W. Zhao ◽  
C. Gleichweit ◽  
K. Gotterbarm ◽  
U. Bauer ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
X Ray ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

scholarly journals Nitrogen-Doped Graphene: The Influence of Doping Level on the Charge-Transfer Resistance and Apparent Heterogeneous Electron Transfer Rate

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1815 ◽  
Author(s):  
Maria Coros ◽  
Codruta Varodi ◽  
Florina Pogacean ◽  
Emese Gal ◽  
Stela M. Pruneanu
Keyword(s):  
Doping Level ◽  
Transfer Rate ◽  
Charge Transfer Resistance ◽  
Electron Transfer Rate ◽  
Transfer Resistance ◽  
X Ray ◽  
Nitrogen Doped ◽  
Heterogeneous Electron Transfer ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

Three nitrogen-doped graphene samples were synthesized by the hydrothermal method using urea as doping/reducing agent for graphene oxide (GO), previously dispersed in water. The mixture was poured into an autoclave and placed in the oven at 160 °C for 3, 8 and 12 h. The samples were correspondingly denoted NGr-1, NGr-2 and NGr-3. The effect of the reaction time on the morphology, structure and electrochemical properties of the resulting materials was thoroughly investigated using scanning electron microscopy (SEM) Raman spectroscopy, X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), elemental analysis, Cyclic Voltammetry (CV) and electrochemical impedance spectroscopy (EIS). For NGr-1 and NGr-2, the nitrogen concentration obtained from elemental analysis was around 6.36 wt%. In the case of NGr-3, a slightly higher concentration of 6.85 wt% was obtained. The electrochemical studies performed with NGr modified electrodes proved that the charge-transfer resistance (Rct) and the apparent heterogeneous electron transfer rate constant (Kapp) depend not only on the nitrogen doping level but also on the type of nitrogen atoms found at the surface (pyrrolic-N, pyridinic-N or graphitic-N). In our case, the NGr-1 sample which has the lowest doping level and the highest concentration of pyrrolic-N among all nitrogen-doped samples exhibits the best electrochemical parameters: a very small Rct (38.3 Ω), a large Kapp (13.9 × 10−2 cm/s) and the best electrochemical response towards 8-hydroxy-2′-deoxyguanosine detection (8-OHdG).

High Reversible Capacity of Nitrogen-Doped Graphene as an Anode Material for Lithium-Ion Batteries

2014 ◽  
Vol 1070-1072 ◽  
pp. 459-464
Author(s):  
Chang Jing Fu ◽  
Shuang Li ◽  
Qian Wang
Keyword(s):  
Graphene Oxide ◽  
Electron Microscope ◽  
Lithium Ion Batteries ◽  
Current Density ◽  
Lithium Ion ◽  
X Ray ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene ◽  
A Current

Nitrogen-doped graphene (N-rGO) was synthesized in the process of preparation of reduced graphene oxide from the expanded graphite through the improved Hummers’ method. The morphology, structure and composition of nitrogen-doped graphene oxide (GO) and N-rGO were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The nitrogen content of N-rGO was approximately 5 at.%. The electrochemical performances of N-rGO as anode materials for lithium-ion batteries were evaluated in coin-type cells versus metallic lithium. Results showed that the obtained N-rGO exhibited a higher reversible specific capacity of 519 mAh g-1 at a current density of 100 mA⋅g-1 and 207.5 mAh⋅g-1 at a current density of 2000 mA⋅g-1. The excellent cycling stability and high-rate capability of N-rGO as anodes of lithium-ion battery were attributed to the large number of surface defects caused by the nitrogen doping, which facilitates the fast transport of Li-ion and electron on the interface of electrolyte/electrode.

Effects of buffer gas on N-doped graphene in a non-thermal plasma process

2021 ◽  
pp. 108548
Author(s):  
Zhongshan Lu ◽  
Cheng Wang ◽  
Xianhui Chen ◽  
Ming Song ◽  
Weidong Xia
Keyword(s):  
Thermal Plasma ◽  
Buffer Gas ◽  
Plasma Process ◽  
Doped Graphene ◽  
Non Thermal Plasma ◽  
Thermal Plasma Process

Fabrication and Electrochemical Performance of Nitrogen-Doped Graphene Synthesized by Hydrothermal Method

2014 ◽  
Vol 804 ◽  
pp. 35-38
Author(s):  
Sen Liang ◽  
Min Luo ◽  
Yuan Yun Dou ◽  
Lei Guo ◽  
Bin Liang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Electrical Measurements ◽  
X Ray ◽  
Nitrogen Doped ◽  
Reduced Graphene ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene ◽  
Nitrogen Substitution ◽  
Pyridinic N

In this study, nitrogen doped graphene (NG) was prepared by using hydrothermal treatment of graphene oxide (GO) and ethylene diamine (EDA). The surface chemistry of the reduced graphene oxide (rGO) and the NG was investigated by the X-ray photoelectron spectroscopy (XPS). The results revealed that there were four kinds of nitrogen substitution: pyrollic N, pyridinic N, graphitic N and C-NH2. Further, the electrical measurements illustrated that the NG had superior capacitive performance than that of the rGO. Specifically, the maximum specific capacitance of NG was 200.6 F/g due to the double-layer capacitive and pseudocapacitive effect from the nitrogen-doped graphene. In addition, the present studies showed that the EDA was not only choose as nitrogen doping source but also played a key role in reduction.

scholarly journals In situ synthesis of copper nanoparticles encapsulated by nitrogen-doped graphene at room temperature via solution plasma

RSC Advances ◽  
2020 ◽  
Vol 10 (60) ◽  
pp. 36627-36635
Author(s):  
Phu Quoc Phan ◽  
Sangwoo Chae ◽  
Phuwadej Pornaroontham ◽  
Yukihiro Muta ◽  
Kyusung Kim ◽  
...  
Keyword(s):  
Copper Nanoparticles ◽  
Room Temperature ◽  
In Situ Synthesis ◽  
Plasma Process ◽  
Nitrogen Doped ◽  
Layer Graphene ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene ◽  
Few Layer Graphene

An excellent corrosion protection for copper nanoparticles by nitrogen-doped few-layer graphene via solution plasma process.

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