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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 Raman spectra of GO-OOH (a), GO (b),GO-N-180 (c), GO-OOH-N (d), GO-N (e); bID/IG value
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Fig2: a Raman spectra of GO-OOH (a), GO (b),GO-N-180 (c), GO-OOH-N (d), GO-N (e); bID/IG value

Mentions: Figure 2 shows the Raman spectra of natural graphite, GO, GO-OOH, GO-N, GO-N-180, and GO-OOH-N. All spectra show two characteristic peaks of graphitic carbon materials as G band near 1580 cm−1 and D band near 1350 cm−1, representing the degree of crystallization and the degree of disorder or defect in the samples, respectively. The former is caused by in-plane stretching vibration under the E2g mode, and the latter is caused by the scattering of phonons at the boundary of the disordered hexagonal Brillouin zone [36]. It can be seen from the inset in Fig. 2a that the crystallization degree of original graphite was very high (ID/IG = 0.14). After oxidization treatment, the crystallization degree of GO decreased obviously due to the oxygen-containing groups induced. For the carboxylic graphene, broadening of D band indicates more disorder of the structure, which is related to the increase of oxygen content and the size reduction caused by bond breaking in a transition from C-O-C to -COOH. By nitrogen doping and reduction treatment, N-doped graphene samples were obtained, with a small reduction in ID/IG value (from 1.08 to 1.01). This is the result of the combined action of several factors: (1) reduction of oxygen-containing groups led to decrease of ID/IG value; and (2) more structural defects of graphene caused by N doping would increase the value of ID/IG; the ID/IG values of GO-N, GO-N-180, and GO-OOH-N were similar, indicating close defect density of the N-doped samples but different defect type and distribution, as confirmed by XPS results.Fig. 2


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 Raman spectra of GO-OOH (a), GO (b),GO-N-180 (c), GO-OOH-N (d), GO-N (e); bID/IG value
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig2: a Raman spectra of GO-OOH (a), GO (b),GO-N-180 (c), GO-OOH-N (d), GO-N (e); bID/IG value
Mentions: Figure 2 shows the Raman spectra of natural graphite, GO, GO-OOH, GO-N, GO-N-180, and GO-OOH-N. All spectra show two characteristic peaks of graphitic carbon materials as G band near 1580 cm−1 and D band near 1350 cm−1, representing the degree of crystallization and the degree of disorder or defect in the samples, respectively. The former is caused by in-plane stretching vibration under the E2g mode, and the latter is caused by the scattering of phonons at the boundary of the disordered hexagonal Brillouin zone [36]. It can be seen from the inset in Fig. 2a that the crystallization degree of original graphite was very high (ID/IG = 0.14). After oxidization treatment, the crystallization degree of GO decreased obviously due to the oxygen-containing groups induced. For the carboxylic graphene, broadening of D band indicates more disorder of the structure, which is related to the increase of oxygen content and the size reduction caused by bond breaking in a transition from C-O-C to -COOH. By nitrogen doping and reduction treatment, N-doped graphene samples were obtained, with a small reduction in ID/IG value (from 1.08 to 1.01). This is the result of the combined action of several factors: (1) reduction of oxygen-containing groups led to decrease of ID/IG value; and (2) more structural defects of graphene caused by N doping would increase the value of ID/IG; the ID/IG values of GO-N, GO-N-180, and GO-OOH-N were similar, indicating close defect density of the N-doped samples but different defect type and distribution, as confirmed by XPS results.Fig. 2

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.