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| 題名: | Superhydrophilic graphite surfaces and water-dispersible graphite colloids by electrochemical exfoliation |
| 作者: | 曹恆光;Li, Yueh-Feng;Chen, Shih-Ming;Lai, Wei-Hao;Sheng, Yu-Jane;Tsao, Heng-Kwong |
| 貢獻者: | 工學院化學工程與材料工程學系 |
| 關鍵詞: | ANODES;COLLOIDS;Contact angle;ELECTROLYSIS;Exfoliation;GRAPHITE;INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY;MATERIALS SCIENCE;OXIDATION;OXIDES;OXYGEN;RAMAN SPECTRA;RAMAN SPECTROSCOPY;SCANNING ELECTRON MICROSCOPY;Shells;SURFACES;THERMAL GRAVIMETRIC ANALYSIS;X-RAY PHOTOELECTRON SPECTROSCOPY |
| 日期: | 2013-08-14 |
| 上傳時間: | 2026-04-21 14:13:30 (UTC+8) |
| 出版者: | American Institute of Physics;United States: AIP Publishing |
| 摘要: | 摘要： Superhydrophilic graphite surfaces and water-dispersible graphite colloids are obtained by electrochemical exfoliation with hydrophobic graphite electrodes. Such counterintuitive characteristics are caused by partial oxidation and investigated by examining both graphite electrodes and exfoliated particles after electrolysis. The extent of surface oxidation can be explored through contact angle measurement, scanning electron microscope, electrical sheet resistance, x-ray photoelectron spectroscopy, zeta-potential analyzer, thermogravimetric analysis, UV-visible, and Raman spectroscopy. The degree of wettability of the graphite anode can be altered by the electrolytic current and time. The water contact angle declines generally with increasing the electrolytic current or time. After a sufficient time, the graphite anode becomes superhydrophilic and its hydrophobicity can be recovered by peeling with adhesive tape. This consequence reveals that the anodic graphite is oxidized by oxygen bubbles but the oxidation just occurs at the outer layers of the graphite sheet. Moreover, the characteristics of oxidation revealed by UV peak shift, peak ratio between D and G bands, and negative zeta-potential indicate the presence of graphite oxide on the outer shell of the exfoliated colloids. However, thermogravimetric analysis for the extent of decomposition of oxygen functional groups verifies that the amount of oxygen groups is significantly less than that of graphite oxide prepared via Hummer method. The structure of this partially oxidized graphite may consist of a graphite core covered with an oxidized shell. The properties of the exfoliated colloids are also influenced by pH of the electrolytic solution. As pH is increased, the extent of oxidation descends and the thickness of oxidized shell decreases. Those results reveal that the degree of oxidation of exfoliated nanoparticles can be manipulated simply by controlling pH.
其他題名： J Chem Phys
出版者： United States: AIP Publishing
出版日期： 2013-08-14
出處： The Journal of Chemical Physics, 2013-08, Vol.139 (6), p.064703
資源來源： AIP Journals (American Institute of Physics)
識別號： ISSN: 0021-9606
識別號： ISSN: 1089-7690
識別號： EISSN: 1089-7690
識別號： DOI: 10.1063/1.4817680
識別號： PMID: 23947876 |
| 顯示於類別: | [化學工程與材料工程學系 ] 期刊論文
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