單一原子層金屬M(Pt,Au,Pd,Ir)沉積修飾E-TEK商用觸媒Pt/C與PtRu/C

Abstract

本研究將燃料電池商用觸媒E-TEK 之Pt/C與PtRu/C當作基礎樣品。先將商用觸媒先進行前處理，以氫氣低溫低壓還原觸媒表面成金屬狀態。再分別將還原後的觸媒，沉積單一原子層M(M=Pt, Au, Pd, Ir 等貴重金屬)。我們可藉由調整不同前驅物的濃度、pH值、溫度、前驅物錯合物種類等等因素有效地控制與選擇性的成長單一原子層M金屬在商用觸媒Pt/C與PtRu/C表面。修飾觸媒結構製作完成後會進行材料特性測試，包含利用X光繞射分析(X-ray diffraction analysis)、電化學X光吸收光譜分析(Electrochemical X-ray absorption spectroscopy 國家同步輻射中心光源)，鑑定觸媒材料的結構與原子分佈情況，X光光電子光譜分系(X-ray photoelectron spectroscopy)分析了解觸媒金屬的氧化態與元素比例，再將樣品透過HR-TEM顯微鏡分析與觀察其實際結構與形貌。最後我們利用恆電位儀(potentiostat)半電池測試其觸媒活性與穩定性，再配合交流阻抗分析 (ac impedance)，了解觸媒在運作時期阻抗變化情形。最終我們利用全電池系統分別比較修飾過後觸媒與原來商用觸媒的活性與效能穩定性比較。我們預期以選擇性單一原子層沉積之商用觸媒將有顯著的效能提升，並且具有較佳的長時間穩定性結果。

This proposal is concerned with the surface modification of commercially available E-TEK Pt/C and PtRu/C via a displacement reaction to deposit monolayer M (M=Pt, Au, Pd, Ir). The as-received Pt/C and PtRu/C was subjected to a H2 reduction followed by immersing into an electrolyte with suitable cations for deposition. The activities for the cations were adjusted by varying precursor concentration, pH, temperature, and type of complexing agents so a monolayer can be formed on the surface of Pt/C and PtRu/C. After surface modification, detailed characterizations such as X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, electrochemical analysis, transmission electron microscope, and ac impedance will be carried out to investigate the microstructure, morphological evolution, and electrocatalytic properties. We hope to obtain significant improvements for the catalytic activities after mono-layered deposition of suitable atoms.