應用於燃料電池氧氣還原反應之含氮鐵鉑觸媒合成與特性分析

Nitrogen containing FePt Catalyst in Oxygen Reduction Reaction for Fuel Cells

陳宣宏(Syuan-Hong Chen)

指導教授 ： 劉如熹

國立臺灣大學/理學院/化學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.02754

摘要

為加速燃料電池之實用化，開發具高活性、高穩定性與低成本之陰極觸媒為科學界之一大課題。近年藉沉積鐵氮碳奈米粒子於零維碳材或二維結構之石墨烯，並於氨氣環境進行熱處理，開發具一定活性、低雙氧水產率與近四電子轉移數之過渡金屬觸媒，但其活性與鉑等貴金屬觸媒仍有一定差距。
因觸媒催化能力與其結構具顯著相關性，藉調控觸媒之結構，可改善其對氧氣還原反應之活性以及副反應之產生。本研究將藉添加鉑金屬於鐵氮粒子之結構，藉由鉑較鐵富電子之特性，改善鐵氮觸媒之活性，並藉此為爾後富電子金屬改質方法之研究奠定基礎。此外此合成法將觸媒乘載於將金屬離子結合之熬合劑碳化所形成之碳材。不似過往金屬觸媒合成後，需額外添加碳材再經熱處理之方法，流程精簡。相較於已發展之合金觸媒，本研究所開發之觸媒具降低成本之優勢並可有效提升此非貴重金屬觸媒之催化活性。
藉調整合成方法後，本研究以X光粉末繞射儀(X-ray powder diffraction; XRD)鑑定觸媒晶體結構與純度；以感應耦合電漿質譜分析儀(inductively coupled plasma mass spectrometry; ICP-MS)與元素分析儀(elemental analyzer; EA)分析觸媒元素組成，藉穿透式電子顯微鏡(transmission electron microscopy; TEM)進行觸媒形貌、粒徑大小與分布之分析，以循環伏安電位儀(cyclic voltammetry)量測觸媒之電化學特性、氧氣還原(ORR)活性與雙氧水產生率，以X光吸收光譜(X-ray absorption spectroscopy; XAS)之X光近吸收邊緣結構(X-ray Absorption Near Edge Structure; XANES)量測觸媒元素之電子結構。藉由上述方法，確認藉添加鉑金屬於鐵氮粒子之結構將改善鐵氮觸媒之活性。

關鍵字

燃料電池 ； 觸媒 ； 氧氣還原

並列摘要

To promote the commercial of fuel cell, designing a high activity, high stability and low cost catalyst was a critical issue. Recently, the catalyst which iron nitride nanoparticle deposited on the zero dimensional and three dimensional carbon support was synthesized under the ammonia atmosphere and demonstrated a well performance in activity, electron transfer and yield of hydrogen peroxide in oxygen reduction reaction. However, its activity was still lower than commercial Platinum catalyst.
The electronic structure was an important factor to enhance the activity and inhabit the side reaction of catalyst. In present study, we established method to improve the activity by importing an electron donor, platinum for example, into the iron nitride catalyst enhance the back donation of active site.
In the present study, the characteristics of catalyst were identified by following technology. Crystal structure identified X-ray powder diffraction. X-ray Absorption Near Edge Structure (XANES) study by using synchrotron radiation was applied for the d-band vacancy of iron and platinum. The oxygen reduction performance was identified by cyclic voltammery. Confirm the introduction of platinum into iron nitride catalyst would enhance the catalytic activity.

並列關鍵字

fuel cell ； catalysts ； oxygen reduction reaction

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