| 摘要: | 目前電解水產氫為最具潛力的再生能源之一，但整體水分解效率受限於陽極產氧反應之動力學障礙。當今產氧效能較佳的材料為IrO2和RuO2，由於其價格昂貴且含量稀少，使得難以大規模生產。為解決上述問題，本研究以微陽極導引電鍍法(Micro-anode guided electroplating, MAGE)製備鎳鈷鐵三元、鎳鈷鐵鉻四元合金微柱作為陽極之催化電極，並探討其在鹼性環境(1.0 M KOH)中之產氧性能。本製程固定析鍍參數為電壓4.0 V與間距100 μm，並分別改變鍍浴中亞鐵離子濃度(0.03 M~0.06 M)及鉻離子濃度(0.0 mM~2.5 mM)進行析鍍。將所得之合金微柱以SEM觀察表面形貌、EDS分析化學組成、XRD分析晶體結構。接著進行線性掃描伏安法、循環伏安法、計時電位法與電化學阻抗頻譜之電化學測試，探討合金微柱之產氧效能。結果顯示鎳鈷鐵鉻合金比鎳鈷鐵合金有更佳產氧效能，其中具有最佳產氧效能的為Ni21Co33Fe34Cr12 (NCFR20)，塔弗斜率60.7 mV/dec為最低，產氧起始電位1.41 V為最低，循環伏安法最大電流密度為1525 mA/cm2，電荷轉移電阻僅51.09 Ω·cm2，且僅需1.50 V就可以維持電流密度在100 mA/cm2。本研究也證實添加鉻元素有利於電荷轉移使催化電極具更佳之產氧效能。;At present, hydrogen production by water electrolysis is one of the most potential renewable energy sources, but the overall water splitting efficiency is limited by the kinetic barrier of oxygen evolution reaction at the anode. IrO2 and RuO2 have better oxygen evolution efficiency nowadays, which are difficult to produce on a large scale due to their high price and scarcity. In this study, Micro-anode guided electroplating (MAGE) was used to prepare nickel-cobalt-iron ternary and nickel-cobalt-iron-chromium quaternary alloy microcolumns as anode catalytic electrodes, and to discuss their performance for oxygen generation in alkaline media (1.0 M KOH). In this process, the bias voltage is fixed at 4.0 V and the gap is 100 μm, and the concentration of ferrous ions (0.03 M~0.06 M) and chromium ions (0.0 mM~2.5 mM) in the electroplating bath are respectively changed for fabrication. The surface morphology of the microcolumns was observed by SEM, the chemical composition was analyzed by EDS, and the crystal structure was analyzed by XRD. Subsequently, different alloy microcolumns were immersed in 1.0 M KOH for electrochemical tests such as linear sweep voltammetry, cyclic voltammetry, chronopotentiometry, and electrochemical impedance spectroscopy to observe oxygen evolution efficiency of alloy microcolumns. The results show that nickel-cobalt-iron-chromium alloy has better oxygen evolution efficiency than nickel-cobalt-iron alloy, and Ni21Co33Fe34Cr12 (NCFR20) has the best oxygen evolution performance, with the lowest Tafel slope of 60.7 mV/dec, and the lowest onset potential of oxygen evolution is 1.41 V, the maximum current density of cyclic voltammetry is 1525 mA/cm2, the charge transfer resistance is only 51.09 Ω·cm2, and only 1.50 V is needed to maintain the current density at 100 mA/cm2. This study also confirmed that the addition of chromium is beneficial for the charge transfer, so that the catalytic electrode has a better oxygen evolution efficiency. |
