中國有色金屬學(xué)報(bào)
ZHONGGUO YOUSEJINSHU XUEBAO
| 第18卷 第11期 總第116期 2008年11月 |
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文章編號(hào)：1004-0609(2008)11-2044-06
碳載Pd-Co-Au合金納米粒子的制備及其電催化性能
王文明1, 2，李曉偉1，鄒志清1，袁 婷1, 杜 翀1，夏保佳1，楊 輝1
(1. 中國科學(xué)院 上海微系統(tǒng)與信息技術(shù)研究所，上海 200050；
2. 湖南省電力勘測設(shè)計(jì)院，長沙 410007)
摘 要: 采用乙二醇還原法并進(jìn)一步熱處理制備碳載Pd-Co-Au (Pd-Co-Au/C)三元合金納米電催化劑，通過旋轉(zhuǎn)圓盤和環(huán)盤電極等技術(shù)評(píng)價(jià)催化劑對(duì)氧氣還原反應(yīng)的電催化活性，并分析氧氣還原的機(jī)理。結(jié)果表明：合成Pd-Co-Au/C催化劑中Pd和Au兩相面心立方(fcc)結(jié)構(gòu)共存，且隨著熱處理溫度的提高，對(duì)應(yīng)于Au的衍射峰強(qiáng)度減弱，而Pd衍射峰強(qiáng)度增強(qiáng)；當(dāng)溫度高于800 ℃時(shí)，形成具有Pd單相fcc結(jié)構(gòu)的三元合金納米催化劑。氧氣還原反應(yīng)的動(dòng)力學(xué)表明：氧氣在Pd-Co-Au/C三元合金催化劑上按4e路徑還原為水。電化學(xué)表征表明，在酸性介質(zhì)中，經(jīng)800 ℃熱處理的Pd7Co2Au1/C催化劑對(duì)氧氣還原的電催化活性最高，接近于商業(yè)化Pt/C的性能；而在含甲醇的酸性介質(zhì)中，Pd-Co-Au/C催化劑電催化氧氣還原的活性顯著高于Pt/C。因此，Pd-Co-Au/C是一種高抗甲醇的新型氧氣還原反應(yīng)電催化劑。
關(guān)鍵字: Pd合金；納米粒子；氧還原反應(yīng)；電催化；抗甲醇
Preparation and electrocatalysis of carbon-supported Pd-Co-Au ternary alloy nanoparticles
WANG Wen-ming1, 2, LI Xiao-wei1, ZOU Zhi-qing1, YUAN Ting1, DU Chong1, XIA Bao-jia1, YANG Hui1
（1. Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences,Shanghai 200050, China;
2. Hunan Electric Power Design Institute, Changsha 410007, China）
Abstract:Carbon-supported Pd-Co-Au ternary alloy nanoparticle electrocatalysts were prepared by modified polyol reduction, and then heat-treated at 500−900 ℃. The electrocatalytic activities for the oxygen reduction reaction (ORR) were investigated based on porous rotating disk and disk-ring electrode techniques. The results show that the as-prepared Pd-Co-Au/C catalysts have broad reflections corresponding to the mixed Au and Pd face centred cubic (fcc) phases and the intensity of Au-rich phase relative to Pd-rich phase decreases with the increase of heat treatment temperature. When the heat treatment temperature is higher than 800 ℃, Pd ternary alloys with Pd fcc structure form. The electrochemical measurements indicate that the maximum catalytic activity for the ORR is found on the Pd7Co2Au1/C catalyst heat-treated at 800 ℃, which is close to the commercially available Pt/C. Kinetic analysis reveals that the ORR on Pd-Co-Au/C undergoes a four-electron process to water. Since Pd-Co-Au/C catalysts are inactive for the adsorption and oxidation of methanol, thus, they can be used as a new type of promising catalyst for methanol-tolerant ORR in a direct methanol fuel cell.
Key words: Pd alloy; nanoparticle; oxygen reduction reaction; electrocatalysis; methanol tolerance
