本研究以含聚乙烯亞胺之聚丙烯醚擬樹枝狀高分子D400(EI)8、D400(EI)20為保護劑，以化學還原法於水相製備鉑奈米粒子。D400(EI)8於水中能迅速螯合鉑離子，達到保護之效果。探討改變[N]/[Pt]值及pH值對製備之鉑粒子之影響，發現當[N]/[Pt]值大於20時，鉑粒子之聚集情形獲得改善；隨pH值增加到pH = 5.2，鉑粒子之粒徑略為縮小，而聚集之情形也較為改善。由動態粒徑分析儀(DLS)與zeta-potential之量測，對照TEM高分子染色法之結果可以得到高分子聚集體於Pt4+/Pt0存在時發生之變化，並以此探討D400(EI)8穩定粒子之方法。

　　以弱還原劑(乙二醇)製備非等向鉑奈米粒子之研究中，還原溫度過低不利於鉑離子之還原，而還原溫度過高則形成之粒子形狀較不規則。以改變pH值對製備非等向粒子作探討時，發現於pH = 3時較利於製備形態規則之方形鉑奈米粒子，而較pH值大於7時鉑離子之還原受到限制。

　　以D400(EI)20製備之奈米粒子分散於碳黑表面時，較高[N]/[Pt]值製備之鉑粒子較不易吸附於碳黑表面。以PEGDE交聯分散於碳黑表面鉑粒子上之D400(EI)20，可以將碳黑固定於碳布之表面，製備觸煤碳布。

　　Zerovalent platinum (Pt0) nanoparticles were prepared under the protection of dumbbell-like ABA hyperbranch-polyethyleniminated polyoxypropylenediamines copolymer (D400(EI)8), and the roles of polymer were studied by UV-Vis spectra, DLS and TEM measurements. Furthermore, the effects of Pt4+/Pt0 on the conformation of D400(EI)8 in aqueous solution were also investigated. From UV-Vis spectra results, fast ligand exchange between chlorine ligand in H2PtCl6 and amino groups in D400(EI)8 copolymer were observed. Size of resulted Pt0 nanoparticles can be controllably decreased by increasing [N]/[Pt] ratio in the present of Pt4+ ions coordinated with D400(EI)8 followed by the chemical reduction of NaBH4, e.g. 2~3 nm at [N]/[Pt] = 10 and 1 nm at [N]/[Pt] = 20. Direct evidences accomplished by phosphotungstic acid (PTA) positive staining technique have been revealed that the reduced Pt0 nanoparticles are located in the PTA stained dark area and well-protected by the polyethylenimine (PEI) blocks at the exterior of micelles, whereas the polyoxypropylene (PPO) blocks surrounded by PEI blocks are in position of bright area. DLS measurements show that the micelle size of D400(EI)8 becomes smaller with narrowed distribution and the positive-charge zeta potential of micelle is significantly increased after the introduction of H2PtCl6 salt in aqueous solution.

　　In the experiments that using EG as reductant, UV-Vis spectra and TEM micrographs indicated that 140oC is the most suitable reducing temperature for preparing uniform shaped Pt nanoparticles. Moreover, the pH values of solutions affect the shape of reduced nanoparticles also. Cubic shaped Pt nanocrystals can be formed under acidic pH 3.

　　D400(EI)20 stabilized platinum particles were made for preparing catalyst layer of DMFC. Platinum particles preparing in the presence of higher [N]/[Pt] values were unsuitable for preparing platinum supported carbon black catalysts due to the well protection under high [N]/[Pt] values.

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