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Carboxyl-Assisted Synthesis of Nitrogen-Doped Graphene Sheets for Supercapacitor Applications.

Xie B, Chen Y, Yu M, Shen X, Lei H, Xie T, Zhang Y, Wu Y - Nanoscale Res Lett (2015)

Bottom Line: The structure of the N-doped graphene with different surface functional groups was characterized by Raman spectroscopy.The research result indicates that the carboxylation of GO is the key factor to obtain pyridinic and pyridone N types during the N atom doping process.Compared to general N-doped graphene, the electrochemical test shows that specific capacitance of the GO-OOH-N sample reaches up to 217 F/g at a discharge current density 1 A/g and stable cycling performance (keep 88.8 % specific capacitance after 500 cycles at the same discharge current density) when applied to the supercapacitor electrode materials.

View Article: PubMed Central - PubMed

Affiliation: Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan 388 Lumo RD, Wuhan, 430074, China, 391856294@qq.com.

ABSTRACT
The high ratio of pyridinic and pyridone N-doped graphene sheets have been synthesized by functionalizing graphene oxide (GO) with different oxygen groups on its surface. The typical N-doped graphene was determined to be ~3-5 layers by transmission electron microscopy (TEM) and atomic force microscopy (AFM), and the nitrogen content was measured as 6.8-8 at. % by X-ray photoelectron spectroscopy (XPS). The structure of the N-doped graphene with different surface functional groups was characterized by Raman spectroscopy. The research result indicates that the carboxylation of GO is the key factor to obtain pyridinic and pyridone N types during the N atom doping process. Compared to general N-doped graphene, the electrochemical test shows that specific capacitance of the GO-OOH-N sample reaches up to 217 F/g at a discharge current density 1 A/g and stable cycling performance (keep 88.8 % specific capacitance after 500 cycles at the same discharge current density) when applied to the supercapacitor electrode materials.

No MeSH data available.


a, b is the TEM image and AFM image of graphene oxide; c is TEM image of N-doped graphene
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Fig1: a, b is the TEM image and AFM image of graphene oxide; c is TEM image of N-doped graphene

Mentions: Figure 1a shows TEM image of the graphene oxide (GO) with high transparence and displays gauze-like morphology. The GO has slight folds and crimped edges due to the oxygen functional groups that produced defects on the sample surface and edges. The thickness of GO can be determined by AFM (Fig. 1b), which shows that the thickness distribution of GO is relatively uniform with two to three layers [34]. After the nitrogen doping treatment (Fig. 1c), wrinkled degree of the graphene surface aggravated obviously because of the more defect formation and the N atoms induced into the graphene. Notably, the nitrogen-doped graphene with a pre-carboxylation treatment on GO precursor exhibits better disperse ability in ethanol (see Additional file 1: Figure S1), illustrating that adequate oxygen-containing groups were still remained in GO-OOH-N after hydrothermal reduction. The N-doped process and mechanism are similar to the bamboo-shaped feature of nitrogen-doped carbon nanotubes [35].Fig. 1


Carboxyl-Assisted Synthesis of Nitrogen-Doped Graphene Sheets for Supercapacitor Applications.

Xie B, Chen Y, Yu M, Shen X, Lei H, Xie T, Zhang Y, Wu Y - Nanoscale Res Lett (2015)

a, b is the TEM image and AFM image of graphene oxide; c is TEM image of N-doped graphene
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542773&req=5

Fig1: a, b is the TEM image and AFM image of graphene oxide; c is TEM image of N-doped graphene
Mentions: Figure 1a shows TEM image of the graphene oxide (GO) with high transparence and displays gauze-like morphology. The GO has slight folds and crimped edges due to the oxygen functional groups that produced defects on the sample surface and edges. The thickness of GO can be determined by AFM (Fig. 1b), which shows that the thickness distribution of GO is relatively uniform with two to three layers [34]. After the nitrogen doping treatment (Fig. 1c), wrinkled degree of the graphene surface aggravated obviously because of the more defect formation and the N atoms induced into the graphene. Notably, the nitrogen-doped graphene with a pre-carboxylation treatment on GO precursor exhibits better disperse ability in ethanol (see Additional file 1: Figure S1), illustrating that adequate oxygen-containing groups were still remained in GO-OOH-N after hydrothermal reduction. The N-doped process and mechanism are similar to the bamboo-shaped feature of nitrogen-doped carbon nanotubes [35].Fig. 1

Bottom Line: The structure of the N-doped graphene with different surface functional groups was characterized by Raman spectroscopy.The research result indicates that the carboxylation of GO is the key factor to obtain pyridinic and pyridone N types during the N atom doping process.Compared to general N-doped graphene, the electrochemical test shows that specific capacitance of the GO-OOH-N sample reaches up to 217 F/g at a discharge current density 1 A/g and stable cycling performance (keep 88.8 % specific capacitance after 500 cycles at the same discharge current density) when applied to the supercapacitor electrode materials.

View Article: PubMed Central - PubMed

Affiliation: Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan 388 Lumo RD, Wuhan, 430074, China, 391856294@qq.com.

ABSTRACT
The high ratio of pyridinic and pyridone N-doped graphene sheets have been synthesized by functionalizing graphene oxide (GO) with different oxygen groups on its surface. The typical N-doped graphene was determined to be ~3-5 layers by transmission electron microscopy (TEM) and atomic force microscopy (AFM), and the nitrogen content was measured as 6.8-8 at. % by X-ray photoelectron spectroscopy (XPS). The structure of the N-doped graphene with different surface functional groups was characterized by Raman spectroscopy. The research result indicates that the carboxylation of GO is the key factor to obtain pyridinic and pyridone N types during the N atom doping process. Compared to general N-doped graphene, the electrochemical test shows that specific capacitance of the GO-OOH-N sample reaches up to 217 F/g at a discharge current density 1 A/g and stable cycling performance (keep 88.8 % specific capacitance after 500 cycles at the same discharge current density) when applied to the supercapacitor electrode materials.

No MeSH data available.