In Situ Electrochemical Raman Spectroscopy of Air-Oxidized Semiconducting Single-Walled Carbon Nanotube Bundles in Aqueous Sulfuric Acid Solution
In Situ Electrochemical Raman Spectroscopy of Air-Oxidized Semiconducting Single-Walled Carbon Nanotube Bundles in Aqueous Sulfuric Acid Solution
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硫酸水溶液中空气氧化半导体单壁碳纳米管束的原位电化学拉曼光谱
DOI：
10.1021/acs.jpcc.5b12057
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Yoshinori Sato
中科院分区：
文献类型：
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作者：
Shin-ichi Ogino;Takashi Itoh;Daiki Mabuchi;Koji Yokoyama;Kenichi Motomiya;Kazuyuki Tohji;Yoshinori Sato
在这项研究中，我们氧化了大约90%的半导体，高度结晶的单壁碳纳米管，（hc-SWCNT）在450 °C的气氛中成束30 min，获得含氧官能团修饰的SWCNT，不仅研究了空气氧化对空气氧化的SWCNT的电化学掺杂的影响本研究利用原位拉曼光谱研究了AO-SWCNT束在硫酸水溶液中的电化学行为，同时也研究了原位电化学拉曼光谱数据与双电层超级电容器（EDLSC）性能之间的关系。在空气中对hc-SWCNTs进行氧化，可以制备出直径分布较小的AO-SWCNTs。当将负电荷施加到用作原位拉曼光谱的三电极电化学电池中的工作电极的AO-SWCNT上时，与空气氧化之前相比，观察到AO-SWCNT的G+线的大的下移。原位拉曼光谱数据表明，随着小直径纳米管/总纳米管比例的增加，碳碳键的弱化作用强于声子能量的重整化作用。相比之下，在向AO-SWCNT施加正电荷的情况下，AO-SWCNT的G+线的上移幅度略大于hc-SWCNT的G+线的上移幅度。每单位质量的流入电荷和AO-SWCNT电极的比电容的G+线的偏移的最大幅度（10.7 cm-1）分别为60.1 C/g和50.1 F/g，这是大于hc-SWCNT电极。原位拉曼光谱是一种有用的方法，通过与未官能化的SWCNT相比G+线的移位的幅度来同时评估小纳米管的直径分布和化学官能化的SWCNT的双电层超级电容器的比电容的增加或减少。
In this study, we oxidized approximately 90% semiconducting, highly crystalline single-walled carbon nanotube (hc-SWCNT) bundles in the atmosphere at 450 °C for 30 min to obtain SWCNTs modified with oxygen-containing functional groups and investigated not only the influence of air oxidation on the electrochemical doping of the air-oxidized SWCNT (AO-SWCNT) bundles in aqueous sulfuric acid solution using in situ Raman spectroscopy, but also the relationship between the in situ electrochemical Raman data and the properties of electric double-layered supercapacitors (EDLSCs). By oxidizing the hc-SWCNTs in air, AO-SWCNTs with a small diameter distribution could be prepared. When a negative charge was applied to the AO-SWCNTs used as a working electrode in a three-electrode electrochemical cell for in situ Raman spectroscopy, a large downshift of the G+line of the AO-SWCNTs was observed compared to that before air oxidation. On increasing the ratio of small-diameter nanotubes/total nanotubes, the Raman data obtained in situ revealed that the effect of the weakening of the C–C bond was stronger than that of the renormalization of the phonon energy. In contrast, in the case of applying a positive charge to the AO-SWCNTs, the magnitude of the upshift of the G+line for the AO-SWCNTs was slightly larger than that for the hc-SWCNTs. The influent electric charges per unit mass and the specific capacitances of the AO-SWCNT electrodes for the maximum magnitude of the shift of the G+line (10.7 cm–1) were 60.1 C/g and 50.1 F/g, respectively, which are larger than those of hc-SWCNT electrodes. In situ Raman spectroscopy is a useful method to simultaneously assess the increase or decrease in the diameter distribution of small nanotubes and the specific capacitances of electric double-layered supercapacitors of chemically functionalized SWCNTs by the magnitude of the shift of the G+line compared to unfunctionalized SWCNTs.