多壁奈米碳管承載鈀金屬基材料應用於電催化反應之研究

Multi-Walled Carbon Nanotubes Supported Palladium-based Material in Electrocatalysis Applications

陳玳延(Dai-Yan Chen)

指導教授 ： 林鴻明

大同大學/工程學院/材料工程學系所/碩士(2009年)

摘要

本研究的主要動機在於合成具催化特性的奈米混成觸媒材料，並探討此催化材料的結構特性以及應用在電催化反應的研究。由於經過酸洗過後的碳管，表面會產生許多酸基與活性基，因此可以在碳管上架接金屬或氧化物。藉由導入擁有高熱傳導性與高表面能之多壁奈米碳管作為支撐的材料，氯化鈀和四氯金酸為前驅物，本研究以多元醇法來合成鈀/多壁奈米碳管和金/鈀/多壁奈米碳管混成材料。
本研究主要合成鈀/多壁奈米碳管和金/鈀/多壁奈米碳管材料，並探討其運用在甲酸的電化學氧化反應特性。利用X光射線繞射儀(XRD)作定性分析，鑑定所合成之奈米觸媒混成材料之結構、熱重分析儀(TGA)決定金屬觸媒在合成材料中之重量百分比、掃描式電子顯微鏡(SEM)來觀察顯微形貌、高解析度穿透式電子顯微鏡(TEM)來解析材料之形態與奈米金屬觸媒顆粒大小。在電化學氧化反應試驗中，以循環伏安法(Cyclic Voltammetry)分析觸媒材料在甲酸電解液進行氧化還原之現象、計時安培分析法(Chronoamperometry) 探討觸媒材料對甲酸氧化反應的催化活性及穩定性。研究結果顯示鈀與鈀-金奈米金屬顆粒可以均勻的分散在多壁奈米碳管上，顆粒大小分別約為5~10nm和20~40nm。在電化學氧化反應試驗中，以多壁的奈米碳管為基材承載鈀金屬的合成材料，具有較佳的氧化能力，在還原的過程中也只需要較低的電位就能將CO去除；由飽和至穩定態的電流強度也具有較佳的催化效能。

關鍵字

觸媒 ； 催化 ； 甲酸

並列摘要

The motivation of this study is to synthesis catalytic nanomaterials and to explore the structure and catalytic properties of the these materials used in electrocatalytic reaction. The purified multi-walled carbon nanotubes have the acid functional groups and defects on the surface that makes easy to attach metals or oxides on carbon nanotubes. High thermal conductivity and surface area of the multi-walled carbon nanotubes (MWCNTs) have been used as supporter to support nano Pd and Au-Pd particles by polyol process using PdCl3 and HAuCl4.4H2O as precursors.
The preparation and characterization of palladium/multi-walled carbon nanotubes (Pd/MWCNTs) and gold/palladium/multi-walled carbon nanotubes (Au-Pd/MWCNTs) hybrid materials towards formic acid oxidation are examined in this research. The structures of the resulting nano-catalyst composite materials are analyzed by X-ray diffraction (XRD) patterns. Thermogravimetry Analyzer (TGA) is used to determine the contents of metal catalyst in the hybrid materials. Scanning Electron Microscope (SEM) and High Resolution Transmission electron microscope (HRTEM) are applied to image the morphologies, structures, sizes and the dispersion of nano catalysts. For the results of electrochemical oxidation reaction, the multi-walled carbon nanotubes supported palladium-based materials have the better electro-oxidation behavior and suppress the poison of CO on catalysts. From the saturation to the steady-state current experiment, it indicates the Au-Pd/MWCNTs catalyst has better catalytic performance with high steady state reaction current.

並列關鍵字

catalytic ； catalytic performance ； formic acid

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