Warped graphitic layers generated by oxidation of fullerene extraction residue and its oxygen reduction catalytic activity
Carbon-based oxygen reduction reaction (ORR) catalysts are regarded as a promising candidate to replace the currently used Pt catalyst in polymer electrolyte fuel cells (PEFCs); however, the active sites remain under discussion. We predicted that warped graphitic layers (WGLs) are responsible for th...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Beilstein-Institut
2019-07-01
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| Series: | Beilstein Journal of Nanotechnology |
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| Online Access: | https://doi.org/10.3762/bjnano.10.137 |
| _version_ | 1818023678413111296 |
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| author | Machiko Takigami Rieko Kobayashi Takafumi Ishii Yasuo Imashiro Jun-ichi Ozaki |
| author_facet | Machiko Takigami Rieko Kobayashi Takafumi Ishii Yasuo Imashiro Jun-ichi Ozaki |
| author_sort | Machiko Takigami |
| collection | DOAJ |
| description | Carbon-based oxygen reduction reaction (ORR) catalysts are regarded as a promising candidate to replace the currently used Pt catalyst in polymer electrolyte fuel cells (PEFCs); however, the active sites remain under discussion. We predicted that warped graphitic layers (WGLs) are responsible for the ORR catalytic activity in some carbon catalysts (i.e., carbon alloy catalysts (CACs)). To prove our assumption, we needed to use WGLs consisting of carbon materials, but without any extrinsic catalytic elements, such as nitrogen, iron, or cobalt, which effectively enhance ORR activity. The present study employed a fullerene extraction residue as a starting material to construct WGLs. The oxidation of the material at 600 °C exposed the WGLs by removing the surrounding amorphous moieties. Transmission electron microscopy (TEM) observations revealed the formation of WGLs by oxidation treatment at 600 °C in an O2/N2 stream. Extending the oxidation time increased the purity of the WGL phase, but also simultaneously increased the concentration of oxygen-containing surface functional groups as monitored by temperature programmed desorption (TPD). The specific ORR activity increased with oxidation up to 1 h and then decreased with the intensive oxidation treatment. Correlations between the specific ORR activity and other parameters confirmed that the development of the WGL and the increase in the O/C ratio are the competing factors determining specific ORR activity. These results explain the maximum specific ORR activity after 1 h of oxidation time. WGLs were found to lower the heat of adsorption for O2 and to increase the occurrence of heterogeneous electron transfer. |
| first_indexed | 2024-12-10T03:48:08Z |
| format | Article |
| id | doaj.art-a9c2487e7a1946d09b90cec0dbbe7a5a |
| institution | Directory Open Access Journal |
| issn | 2190-4286 |
| language | English |
| last_indexed | 2024-12-10T03:48:08Z |
| publishDate | 2019-07-01 |
| publisher | Beilstein-Institut |
| record_format | Article |
| series | Beilstein Journal of Nanotechnology |
| spelling | doaj.art-a9c2487e7a1946d09b90cec0dbbe7a5a2022-12-22T02:03:22ZengBeilstein-InstitutBeilstein Journal of Nanotechnology2190-42862019-07-011011391140010.3762/bjnano.10.1372190-4286-10-137Warped graphitic layers generated by oxidation of fullerene extraction residue and its oxygen reduction catalytic activityMachiko Takigami0Rieko Kobayashi1Takafumi Ishii2Yasuo Imashiro3Jun-ichi Ozaki4Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, JapanGraduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, JapanGraduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, JapanGraduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, JapanGraduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, JapanCarbon-based oxygen reduction reaction (ORR) catalysts are regarded as a promising candidate to replace the currently used Pt catalyst in polymer electrolyte fuel cells (PEFCs); however, the active sites remain under discussion. We predicted that warped graphitic layers (WGLs) are responsible for the ORR catalytic activity in some carbon catalysts (i.e., carbon alloy catalysts (CACs)). To prove our assumption, we needed to use WGLs consisting of carbon materials, but without any extrinsic catalytic elements, such as nitrogen, iron, or cobalt, which effectively enhance ORR activity. The present study employed a fullerene extraction residue as a starting material to construct WGLs. The oxidation of the material at 600 °C exposed the WGLs by removing the surrounding amorphous moieties. Transmission electron microscopy (TEM) observations revealed the formation of WGLs by oxidation treatment at 600 °C in an O2/N2 stream. Extending the oxidation time increased the purity of the WGL phase, but also simultaneously increased the concentration of oxygen-containing surface functional groups as monitored by temperature programmed desorption (TPD). The specific ORR activity increased with oxidation up to 1 h and then decreased with the intensive oxidation treatment. Correlations between the specific ORR activity and other parameters confirmed that the development of the WGL and the increase in the O/C ratio are the competing factors determining specific ORR activity. These results explain the maximum specific ORR activity after 1 h of oxidation time. WGLs were found to lower the heat of adsorption for O2 and to increase the occurrence of heterogeneous electron transfer.https://doi.org/10.3762/bjnano.10.137carbon alloy catalystsfullerene extraction residueoxygen reduction reaction (ORR)polymer electrolyte fuel cellswarped graphitic layers |
| spellingShingle | Machiko Takigami Rieko Kobayashi Takafumi Ishii Yasuo Imashiro Jun-ichi Ozaki Warped graphitic layers generated by oxidation of fullerene extraction residue and its oxygen reduction catalytic activity Beilstein Journal of Nanotechnology carbon alloy catalysts fullerene extraction residue oxygen reduction reaction (ORR) polymer electrolyte fuel cells warped graphitic layers |
| title | Warped graphitic layers generated by oxidation of fullerene extraction residue and its oxygen reduction catalytic activity |
| title_full | Warped graphitic layers generated by oxidation of fullerene extraction residue and its oxygen reduction catalytic activity |
| title_fullStr | Warped graphitic layers generated by oxidation of fullerene extraction residue and its oxygen reduction catalytic activity |
| title_full_unstemmed | Warped graphitic layers generated by oxidation of fullerene extraction residue and its oxygen reduction catalytic activity |
| title_short | Warped graphitic layers generated by oxidation of fullerene extraction residue and its oxygen reduction catalytic activity |
| title_sort | warped graphitic layers generated by oxidation of fullerene extraction residue and its oxygen reduction catalytic activity |
| topic | carbon alloy catalysts fullerene extraction residue oxygen reduction reaction (ORR) polymer electrolyte fuel cells warped graphitic layers |
| url | https://doi.org/10.3762/bjnano.10.137 |
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