均一化再生型燃料電池之三元觸媒的製備和效能研究

Preparation and performance of ternary catalyst in Unitized Regenerative Fuel Cell

洪瑞伯(Ruei-Bo Hong)

指導教授 ： 江右君

元智大學/工程學院/機械工程學系/碩士(2009年)

摘要

本研究建立了利用含浸法和聚合前驅物熱分解法製備Pt-based觸媒的標準操作流程，期能提供作為均一化再生型燃料電池之電極觸媒。目前用於均一化再生型燃料電池的觸媒大多使用PtRu及PtIr，使用PtRu的原因是Ru可以有效的防止氧極的毒化現象；使用PtIr的原因是添加了Ir的Pt-based觸媒具有較佳的可逆性以利於同時進行水電解及燃料電池兩個模式。但PtRu的分散情況較差，而PtIr對毒化可能沒有那麼好的抗性；而添加W元素可具有增加比表面積及抗老化的特性。為了減少觸媒的有效粒徑並降低Pt的用量，本研究將Ru、Ir或W與Pt結合形成三元觸媒，期能製備出在Pt用量減少的情下仍能維持一定水準的Pt-based觸媒。
實驗方法擬使用含浸法合成Pt、PtIr、PtRuIr； PtWIr則使用聚合前驅物熱分解法及微波法進行合成。含浸法及微波法設定在三個不同條件下的pH值進行合成，DPP法則設定在不同條件下的溫度進行合成，並均添加碳管比較合成的情況。碳管的材料分別使用商用奈米碳管，以及對商用奈米碳管進行氧化。並另外合成觸媒/碳管，分析其物理特性及電化學特性。
本研究使用含浸法合成的觸媒具有60%-80%良好的回收率，經由XRD也可以發現有不錯的晶相結構，平均粒徑也可控制在5 nm以下。且發現當與商用碳管結合時Pt/CNT及PtWIr/CNT均具有不錯的電化學表面積。而PtRuIr/CBT及PtIr/CBT由循環伏安圖可得知雖然兩者均有不錯的可逆性，但其活性相對於Pt/CNT及PtWIr/CNT而言性能差上許多。
本實驗發現使用DPP法合成PtWIr/CNT可以得到比含浸法合成Pt/CNT更高的活性，因此未來選擇PtWIr/CNT並進一步改善製程也許對於URFC而言可以多一種有潛力的新選擇。本實驗也建立了一套利用含浸法合成Pt觸媒且具備高回收率，良好的晶格結構及電化學活性的合成方法。

關鍵字

均一化再生型燃料電池 ； 觸媒 ； 奈米碳管 ； 特性分析

並列摘要

This study provides the standard operation procedures of impregnation method and thermal decomposition of a polymeric precursor (DPP) method for the preparations of Pt-based catalysts as the electrode catalysts in unitized regenerative fuel cell (URFC). PtRu and PtIr have been widely used as the electrode catalysts in URFC because Ru can prevent the CO poison and Ir can provide better reversibility both at the water electrolysis mode and at the fuel cell mode. In addition, introduction of W has also been fund to increase specific surface area and resist CO poison. In order to decrease particle size and cost of the catalysts used in URFC, this study combines Pt, Ir, and Ru or W to form the ternary catalysts.
This study used impregnation method to prepare Pt, PtIr, and PtRuIr; thermal decomposition of a polymeric precursor (DPP) method and microwave heating method to prepare PtWIr. For, impregnation and microwave heating method, three different pH values were selected for preparation. For DPP method, the chosen parameter was the heat treatment temperature. And some add Carbon nanotubes to prepare and compare. Carbon nanotubes material the use of commercial carbon nanotubes, respectively, as well as the oxidation of commercial carbon nanotubes. And other synthetic catalyst / carbon nanotubes, analysis of their physical properties and electrochemical properties.
In this study, the use of impregnation catalyst synthesized with 60% -80% good recovery rate, by XRD can also be found to have a good crystalline structure, with an average particle size can also be controlled at below 5 nm. And found that when combining carbon nanotubes with the business when the Pt / CNT and PtWIr / CNT have good electrochemical surface area. And PtRuIr / CBT and PtIr / CBT by the cyclic voltammetry graph we can see that although both have a good reversibility, but its activity compared with Pt / CNT and PtWIr / CNT many poor in terms of performance.
The experiment found that the use of DPP synthesis PtWIr / CNT could be synthesized than impregnation Pt / CNT higher activity, so the next choice PtWIr / CNT and may further improve the manufacturing process in terms of the URFC has the potential to be more than a new choice. This experiment also established a synthesis of the use of Pt catalyst impregnation with a high recovery rate and good lattice structure and the electrochemical activity of the synthetic method.

並列關鍵字

Unitized regenerative fuel cell ； Catalyst ； Carbon nanotubes ； Characterization

參考文獻

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