甲醇還原法製備以Vulcan XC-72及MWCNTs為載體之鉑及鉑釕雙金屬催化劑

Preparation of Vulcan XC-72 or MWCNT supported Pt and PtRu catalysts via methanol reduction method

黃啟銘(Chi-ming Huang)

指導教授 ： 吳溪煌

大同大學/工程學院/材料工程學系所/碩士(2007年)

摘要

利用不同之硝酸酸洗方式來改良並純化Vulcan XC-72及多層壁奈米碳管兩種碳載體，以FTIR觀察不同酸洗方式之影響。發現配合間歇性超音波震盪之酸洗方式可以有效提高碳載體的表面含氧官能基。以甲醇還原法在經酸洗之Vulcan XC-72與多層壁奈米碳管表面分別沉積鉑與鉑釕雙金屬催化劑。以ICP-OES分析濾液組成來推估金屬之沉積量，發現高含氧官能基可提供較多的活化位置給金屬顆粒沉基，並加快催化劑前驅物之還原速率。由XRD與TEM分析發現沉積之金屬顆粒具有良好的分散性，粒徑約1-2nm，且結晶度及合金程度很低。合成之Pt/MWCNT比購買之E-TEK Pt/C具有更好之甲醇電催化性，但仍會有CO中毒的現象。由於鉑釕雙金屬的粒徑非常小，合金程度很低，因此對於CO具有強吸附，抑制其甲醇的電催化特性。

關鍵字

甲醇還原法 ； 催化劑 ； 直接甲醇燃料電池 ； 多層壁奈米碳管

並列摘要

Vulcan XC-72 and MWCNT were treated with nitric acid with/without intermittent ultrasonic vibration, and the effects were revealed with FTIR. It was found that acid washing in company with intermittent ultrasonic vibration can enhance the formation of oxy-functional groups. Vulcan XC-72 or MWCNTs supported Pt and PtRu catalysts were prepared by methanol reduction method. ICP-OES was used to analyze the metal residual in the filtrate to determine the amount of metal deposition. It was found that the higher oxy-functional group in the carbon support is used the more active sites for metal deposition can be provided, and thus the higher rate of metal deposition can be obtained. From the results of XRD and SEM, well dispersed metal particles with low crystallinity, low degree of alloying, and particle size ranging between 1 and 2 nm can be found on the surface of the carbon supports. The synthesized Pt/Vulcan XC-72 shows higher catalysis for methanol electro-oxidation than commercialized 20wt%-Pt/C (E-TEK). However, the prepared PtRu/C catalysts manifest poor catalytic activity of methanol electro-oxidation due to its small particle size and low degree of alloying that induce strong adsorption of CO.

並列關鍵字

catalyst ； methanol reduction method ； DMFC ； MWCNT

參考文獻

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