本論文以二維石墨烯為基材，利用還原法將奈米粒子置放於石墨烯表面， 供作電化學觸媒應用。以兩種合成工藝，研究將石墨烯與金屬或金屬氧化物奈 米粒子製作成奈米複材，並進行於電化學催化反應。本論文利用離子液體作為 還原劑，加上微波加速，合成方型奈米鉑金電化學觸媒開始，進行甲醇氧化反 應應用；確認以石墨烯為碳載體的複合電化學觸媒，能發揮功效後，便合成一 系列鉑金-金/石墨烯，鉑金-鎳/石墨烯，鉑金-鐵/石墨烯等複材，進行電化學觸 媒研究，並將雙金屬奈米粒子石墨烯複合電化學觸媒應用於甲醇氧化反應，甲 酸氧化反應等。另外，鎳-氧化鎳石墨烯電化學觸媒，則是應用於氧還原反應。 上述合成出來的雙金屬奈米觸媒，經由穿透式電子顯微鏡分析，金屬奈米粒子 之粒徑皆為5-15 奈米之間。表面化學電子光譜分析(ESCA)金屬奈米粒子與石 墨烯及高分子表面改質之石墨烯間的作用，顯現出元素化學環境的變化。上述 奈米複合電化學觸媒，亦皆經由Ｘ光繞射儀分析其結晶結構，了解其本質。金 屬奈米粒子鍵結在石墨烯表面的總量，是利用熱重分析在空氣環境下，800oC將石墨烯燃燒去除後之殘重來判斷取得，並供作為分析電化學各種氧化反應， 評估電化學觸媒實驗用量的依據。在甲醇氧化反應分析上，可以得出鉑金-金/ 石墨烯與鉑金-鐵/石墨烯不利於甲醇氧化反應，鉑金-金/石墨烯比較適合甲酸氧 化反應之用。鉑金-鐵/石墨烯無法有效地進行相關的氧化反應。鉑金-鎳/石墨烯 則相當適合進行甲醇氧化反應。利用循環伏安法可以發現鉑金-鎳/石墨烯電化 學分析圖譜上甲醇氧化峰與一氧化碳吸收峰的比值約為3 倍之多，亦即鉑金- 鎳/石墨烯相對能夠有效地防止一氧化碳毒化鉑金觸媒，與方型鉑金/石墨稀效 果相似。至於氧還原反應，則是由非鉑金的鎳-氧化鎳/石墨烯奈米複合電化學 觸媒較為有效。;In this thesis, the electrocatalyst nanocomposites, prepared from metal nanoparticles and graphene, have been studied for performance of their electrocatalysis. There are two synthetic methods employed in preparation: one is the green synthesis in 2-hydroxyethanaminium formate ionic liquid with microwave assistance; the other is the hydrothermal synthesis with metal precursor and modified graphene in one pot. The ionic liquid and microwave assisted synthesis produced cubic Pt nanoparticles on graphene sheet (cubic Pt/G), which were evaluated with performance on methanol oxidation reaction (MOR). The one-pot hydrothermal method produced the PDDA-modified graphene with metal nanoparticles on it (PtAu/PDDA-G, PtNi/PDDA-G, PtFe/PDDA-G or Ni-NiO/PDDA-G). These nanocomposites were examined with transmission electron microscopy (TEM) for morphology and also for nanoparticle sizes. Nanoparticles on the cubic Pt/G are about 5-20 nm in size and those of PtM/PDDA-G and Ni-NiO/PDDA-G are about ~5 nm in size. From the X-ray diffraction analysis, nanoparticles on the PtNi/PDDA-G are a single alloy, to apply to the MOR electrocatalysis. The results of ESCA analysis revealed that nanoparticles on the PtNi/PDDA-G are in elemental environments on the graphene surface. The thermal gravimetric analysis (TGA) was employed for evaluation of amounts of the metal deposited on graphene. As electrocatalyst, the MOR performance of cubic Pt/G is no better than that of commercial Pt on carbon (60wt% Pt/C). However, the anti CO-poisoning capability and the unit mass performance of cubic Pt/G is better those of 60wt% Pt/C. The PtNi/PDDA-G is one of the candidates for anode electrocatalysis for use in direct methanol fuel cells. The Ni-NiO/PDDA-G is also an candidate for fuel cell cathode electrocatalysis in oxygen reduction reaction (ORR) utilization. In addition, the formic acid oxidation reaction utilizating of PtAu/PDDA-G was also investigatied in this thesis.
