本研究利用脈衝式電化學共沉積法(Pulsed Co-electrodeposition)製備釕銥二元合金觸媒(Ruthenium-Iridium Binary Catalyst)，並將其運用於質子交換膜水電解器(Proton Exchange Membrane Water Electrolyzer, PEMWE)的陽極觸媒。利用三氯化釕(Ruthenium(Ⅲ) Chloride Hydrate, RuCl3•3H2O)和三氯化銥(Iridium(Ⅲ) Chloride Hydrate, IrCl3•3H2O)作為前驅物，氯化鉀(Potassium Chloride, KCl)做為輔助電解質以提升電解液之導電度，使溶液中的釕離子和銥離子共同還原於觸媒載體上形成二元觸媒。其中，本研究中選用碳材料做為觸媒載體，包含奈米碳管(Carbon Nanotubes)、有/無微孔層之碳布(Carbon Cloth)。
本實驗的製備條件依序以下面五種操控變因來進行實驗：(1) 不同電鍍電位(2)不同單位脈衝中Ton長度 (3)不同電鍍之質傳速率 (4)不同電鍍總時長 (5)不同電鍍後退火溫度，並從中選擇物理、化學以及電化學特性最佳的釕銥觸媒製程參數作為PEMWE之陽極觸媒使用。
效能測試分為兩部分，首先利用場發射掃描式電子顯微鏡(Field Emission Scanning Electron Microscope, FEG-SEM)和能量散射光譜(Energy dispersive X-ray Spectroscopy, EDS)觀察釕銥觸媒於觸媒載體上的形貌以及元素分布。並且利用X光繞射儀(X-ray Diffractometer, XRD)和X射線光電子能譜(X-ray Photon Spectroscopy, XPS)來分析觸媒中釕和銥元素的晶體結構以及電子價數。最後利用感應耦合電漿質譜分析儀(Inductivity Coupled Plasma-Mass Spectrometer, ICPMS)來分析自製觸媒中的貴重金屬含量。電化學方面使用0.5 M硫酸溶液進行線性掃描伏安法(Linear Sweep Voltammetry, LSV)作為觸媒產氧效能的初步測試與比較，接著利用循環伏安法(Cyclic Voltammetry, CV)來測量觸媒的電化學活性面積(Electrochemical Surface Area, ECSA)、並且以電化學阻抗圖譜(Electrochemical Impedance Spectroscopy, EIS)來分析觸媒的反應阻抗。最後經由PEMWE的全電池測試(Full cell test)來模擬水電解產氫及產氧的實際情形。
經本研究發現，調整電鍍電位和電鍍總時長能直接改變釕銥觸媒的形貌和三維結構。調整電鍍時溶液的攪拌轉速以及單位脈衝的結構則能夠改善電鍍時的陽離子質傳情況，進而影響觸媒形貌以及水電解產氫效率。本研究發現以脈衝式電鍍觸媒於奈米碳管載體，並且調整適當的電鍍電位、電鍍總時長以及電鍍中的質傳速率，能夠製備出高度的三維結構以及均勻分布的釕銥合金觸媒。本研究也發現，釕銥二元觸媒比起純釕觸媒擁有更高的觸媒穩定度，證實銥元素的摻雜會對釕觸媒的晶格產生應力，進而提升原先釕觸媒的觸媒穩定度和觸媒活性。

This study performs pulsed co-electrodeposition to prepare ruthenium-iridium binary catalysts and applied them as anode catalysts in the Proton Exchange Membrane Water Electrolyzer (PEMWE). Ruthenium(Ⅲ) Chloride Hydrate (RuCl3•3H2O) and Iridium(Ⅲ) Chloride Hydrate (IrCl3•3H2O) were employed as precursors, with Potassium Chloride (KCl) serving as the supporting electrolyte to enhance the conductivity of the electrolyte solution. The ruthenium and iridium ions were co-deposited on the catalyst support to form a binary catalyst. In this study, carbon materials are selected as catalyst supports, including carbon nanotubes and carbon cloth with/without a microporous layer.
The experimental conditions were systematically varied in five variables: (1) Different electrodeposition potentials, (2) Different Ton lengths for a single pulse, (3) Different mass transport rates during electrodeposition, (4) Different total electrodeposition durations, and (5) Different post-deposition annealing temperatures. The optimal ruthenium-iridium catalyst preparation parameters, based on the physical, chemical, and electrochemical characteristics, were selected for use as anode catalysts in PEMWE.
Performance testing comprised two parts: firstly, morphological observation and elemental distribution of the ruthenium-iridium catalyst on the catalyst support were conducted using Field Emission Scanning Electron Microscopy (FEG-SEM) and Energy Dispersive X-ray Spectroscopy (EDS). Secondly, the crystal structure of ruthenium and iridium elements in the catalyst and their electron valence were analyzed using X-ray Diffractometer (XRD) and X-ray Photoelectron Spectroscopy (XPS). Inductively Coupled Plasma Mass Spectroscopy (ICPMS) was then performed to analyze the noble metal loading and molar ratio of the homemade catalysts. Electrochemical analysis involved using 0.5 M sulfuric acid solution for Linear sweep voltammetry (LSV) for preliminary testing and comparison of the catalyst's oxygen production efficiency. Next, cyclic voltammetry (CV) is used to measure the electrochemical surface area (ECSA) of the catalyst, and electrochemical impedance spectroscopy (EIS) is employed to analyze the reaction impedance of the homemade catalysts. Finally, full cell tests of the PEMWE were conducted to simulate actual hydrogen and oxygen production through water electrolysis.
The study found that adjusting the electrodeposition potential and total duration directly affected the morphology and three-dimensional structure of the ruthenium-iridium catalyst. Adjusting the agitation of the solution during electrodeposition and the structure of the unit pulse improved the cation mass transfer during electrodeposition, thereby influencing the catalyst morphology and hydrogen production efficiency in water electrolysis. It was discovered that using pulsed electrodeposition of catalysts on carbon nanotube supports, along with appropriate adjustments to the electrodeposition potential, total duration, and mass transport rate during electrodeposition, enabled the preparation of highly three-dimensional structures and uniformly distributed ruthenium-iridium alloy catalysts. The study also found that ruthenium-iridium binary catalysts exhibited higher catalytic stability compared to pure ruthenium catalysts, confirming that the doping of iridium elements induced lattice stress in the ruthenium catalyst, thereby enhancing the catalyst's durability.

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