鉑-鎳雙金屬觸媒結構及電化學活性之研究

Structure and Electrochemical Properties of Bimetallic Pt-Ni Catalysts

巫洸毅(Kuang-Yi Wu)

指導教授 ： 姚學麟

國立中央大學/理學院/化學系/碩士(2008年)

摘要

以大角度X 光繞射及Debye 函數分析以形成羰基複合物方式合成不同金屬比例的以Vulcan XC-72 碳為載體的鉑-鎳奈米粒子，從大角度X 光繞射及Debye 函數模擬分析結果得知，在經由500℃以上高溫還原後，鉑-鎳合金觸媒具面心立方結構，其晶格常數會隨著鎳金屬比例的增加而降低。而經由較低溫200℃還原形成觸媒則可能是不均勻的奈米粒子，其內部應鉑跟鎳金屬原子團。穿透式電子顯微鏡結果指出鉑-鎳奈米粒子均勻分布在碳載體上，且粒徑分布約為３～４奈米。藉由能量分散光譜儀確認觸媒組成比例與起始反應物比例接近。我們使用薄膜旋轉電極實驗方式研究氧氣還原反應，結果顯示
鉑-鎳合金的奈米粒子其電化學活性和鉑為基底的觸媒類似。

關鍵字

奈米粒子 ； 鉑 ； 鎳 ； 觸媒 ； 燃料電池

並列摘要

Vulcan XC-72 cabon-support Pt-Ni nanoparticle catalysts with different Pt/Ni atomic compositions were prepared via the carbonyl complex route and their structures were studied by X-ray diffraction at wide angles(WAXS) and Debye function analysis (DFA). WAXS pattern and DFA simulation revealed that all the as-prepared
Pt-Ni alloy catalysts after higher temperature(500℃) treatment have face-centered cubic structure with lattice constants decreasing with the increase of Ni content. Catalysts prepared by heat treatment at 200℃ appeared to be inhomogeneous made of Ni and Pt mono crystallites. Transmission electron microscopy (TEM) images indicated that Pt-Ni nanoparticles were well dispersed on the surface of the carbon support with a narrow
particle size distribution. Energy-dispersive X-ray analysis (EDX) confirmed that the catalyst compositions were nearly the same as the nominal values. We conducted thin film rotating disk electrode experiments to study the oxygen reduction reaction. Results showed that the electrochemical activity of Pt-Ni alloyed catalysts were nearly the same as that of Pt-based catalysts supported by carbon.

並列關鍵字

nanoparticles ； Pt ； Ni ； catalysts ； fuel cell

參考文獻

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