碩士 / 國立成功大學 / 化學工程學系碩博士班 / 96 / A fresh type of carbon support, sea urchin-like carbon (UC), was synthesized by chemical vapor deposition (CVD) growing carbon nanotubes (CNTs) under acetylene gas onto the iron catalysts, well-distributed carbon spheres, which was prepared by a chelating reagent, tetraethylentriamine (TETA), was reacted with acyl chloride-functionalized carbon as prepared. Controlled the time of CVD, the shape of UC material would be changed. Embedding carbon nanotube, the properties of electro-conductivity and surface areas of the UC materials can be improved.
Recently, a hydrophilic polymer, polyoxypropylenediamine (D400), was used as a stabilizer to prepare Pt colloids, through the reduction of citrate and then heat-treated in situ to prepare Pt nanoparticles. X-ray photoelectron spectroscopy revealed that metallic Pt0 is the predominant species in all Pt catalysts after calcinating. The Pt/C catalysts were prepared by changing the amine molar ratios of D400 to chloroplatinic acid, i.e. [N]/[Pt] = 20, 30, 40 and 60 onto the UC supports. The results appeared the Pt nanoparticle size decreasing with increasing the ratio of [N]/[Pt]. The real catalyst loading onto the different carbon supports could be obtained to compare with identical loading by thermogram analysis.
The electrochemical active areas (EAS) and electrochemical activities of the catalysts were evaluated by cyclic voltammetry. The EAS of Pt/UC catalyst (115.5 m2/g, UC-L) was more then Pt/ original carbon black (LB) catalyst (19 m2/g) and E-TEK (Pt/C, 20wt.%) catalyst (100.6 m2/g). Moreover, the methanol electro-oxidation of Pt/UC was superior to Pt/LB. The smaller Pt nanoparticles, prepared under the [N]/[Pt]= 60, onto the UC support, the peak current density ( If, 956.8 mA cm-2) was 1.5 times of E-TEK catalyst (Pt/C, 20wt.%).
Application for DMFC, the Pt/UC also displayed the great performance compared with different morphology of Pt/C catalysts. The power density of Pt/UC-L showed greater than E-TEK catalyst (Pt/C, 20wt.%) in the high current region. The Pt nanoparticle sizes and carbon supports also exhibited that catalyst activities toward methanol electro-oxidation and conductivity affected the single cell performance. Besides, the research on the Pt/UC catalyst using for a cathode electrode was discussed in this study.
| Identifer | oai:union.ndltd.org:TW/096NCKU5063071 |
| Date | January 2008 |
| Creators | Jing- Ping Wang, 王景平 |
| Contributors | Ping-Lin Kuo, 郭炳林 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | en_US |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 96 |
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