| 摘要: | 本研究係以微陽極導引電鍍法(Micro-anode guided electroplating,
MAGE)製備具三維結構之鈷鐵、鈷鐵鉻合金微柱，析鍍所使用的微陽
極和陰極分別係以直徑為 250 μm 白金絲以及 0.5 mm 銅線所製成，
析鍍時之電壓及間距分別設置為 3.6 V、50 μm，透過改變二元鍍浴中
亞鐵離子濃度(0.15 M~0.30 M)，以及三元鍍浴中鉻離子濃度(2.00
mM~8.00 mM)析鍍合金微柱，其中，添加鉻離子濃度大於 10.00 mM
時的析鍍效率較差，無法析鍍出完整微柱。將上述析鍍之合金微柱個
別以 SEM、EDS 及 XRD 分析其表面形貌、組成成分以及晶體結構等
特性，再以奈米壓痕分析微柱的機械性質，而後將剛析鍍完的微柱置
入 1.0 M KOH(pH = 14)的電解液中，進行各項電化學分析，如線性掃
描伏安法、循環伏安法、計時電位法及電化學交流阻抗，藉此探究各
合金微柱之電化學性質以及其析氧效能。
於研究結果可得，鈷鐵鉻合金微柱- Co32Fe40Cr28的析氧效能為最
佳，無論是起始電位(Eonset = 1.43 V vs RHE)、過電位(η10 = 302 mV)又
或是塔弗斜率(Tafel slope = 62.6 mV/dec)皆為本研究中最低，代表於
析氧反應時所需耗能較少，與貴金屬氧化物 IrO2 之過電位(η10 = 270
mV)相比較，效能還是有些許差距。綜上所述可論證，鈷鐵鉻相較鈷
ii
鐵合金微柱具更優異之析氧效能，其中，鉻的添入可提升合金電極表
面之催化活性。;Micro-anode guided electroplating (MAGE) was used to prepare
cobalt-iron and cobalt-iron-chromium alloy micro columns with three dimensional structure in this study. The microanode and cathode used in
the plating were made of platinum wire with the diameter of 250 μm and
copper wire with the diameter of 0.5 mm, respectively. The voltage and
gap between two electrode were set to 3.6 V and 50 μm, respectively. By
changing the concentration of FeSO4⸱7H2O (0.15 M~0.30 M) in the binary
plating bath and the concentration of Cr2(SO4)3⸱3H2O (2.00 mM~8.00
mM) in the ternary plating bath, which the alloy micro columns were
plated. When the concentration of Cr2(SO4)3⸱3H2O was greater than 10.00
mM, the alloy micro columns couldn’t be plated imcompletely. The alloy
micro columns were plated and analyzed by SEM, EDS and XRD
respectively for their surface morphology, composition, crystal structure
etc, then use nanoindenter to analyze the mechanical properties of the
micro columns. Afterwards, place the as-plated micro columns into the 1.0
M KOH (pH = 14) electrolyte and carry out several electrochemical
analyses, such as linear sweep voltammetry (LSV), cyclic voltammetry
(CV), chronopotentiometry (CP), and electrochemical impedance
spectroscopy (EIS). In order to explore the electrochemical properties of
each alloy micro columns and their oxygen evolution efficiency.
The results show that the cobalt-iron-chromium alloy micro column Co32Fe40Cr28 has the best oxygen evolution performance. Regardless of the
onset potential (Eonset = 1.43 V vs RHE), overpotential (η10 = 302 mV) and
iv
the Tafel slope (62.6 mV/dec) are the lowest in this study. The lower the
value of the above three, the less energy is required for the oxygen
evolution reaction. Besides, there is still a slight gap in the overpotential
between Co32Fe40Cr28 and noble metal oxide IrO2 (η10 = 270 mV). In
summary, it can be demonstrated that cobalt-iron-chromium has better
oxygen evolution performance than cobalt-iron alloy micro columns. And
the incorporation of chromium can improve the catalytic activity of the
alloy electrode surface. |
