本研究使用電沉積技術成功製備出具高電催化特性的雙功能NiFe-LDH/Ni(OH)2雙層薄膜，並在實驗中，探討不同的層狀雙氫氧化物的電催化性能，以及不同的電沉積參數對薄膜的電化學特性與表面特徵之影響。透過SEM、XRD、Raman及XPS來分析薄膜的表面特徵，並使用雙頻道恆電位/電流/交流阻抗儀來量測其電催化性能。
本實驗改變電沉積電壓與時間製備單層之NF3b薄膜與雙層之NF3b/N2與NF3b/N3薄膜。由SEM結果得知NF3b薄膜呈現出直立片狀結構； NF3b/N2呈現出表面具有微小顆粒的直立片狀結構；NF3b/N3呈現出表面平整光滑的直立片狀結構。拉曼量測結果得知NF3b薄膜為NiFe-LDH結構；NF3b/N2與NF3b/N3薄膜為Ni(OH)2結構。
電化學量測結果顯示，NF3b/N2具有最佳的OER電催化性能，
LSV量測可以得到，在200 mA/cm2的電流下，過電勢為257 mV，Tafel斜率值為126 mV/dec。NF3b/N3則具有最佳的HER性能，在-10 mA/cm2的電流下，過電勢為-151 mV，Tafel斜率值為86 mV/dec。本實驗將NF3b/N2薄膜與NF3b/N3薄膜作為電極，使用1 M KOH作為電解質，組裝成簡易的鹼性電解槽，並測試用於整體水分解的電催化性能，在LSV量測中得到，在10 mA/cm2的電流下，所需電壓為1.63 V，在CstC的測試中也顯現出良好的穩定性。

In this research, 1st-layer Ni-Fe-LDH/2nd-layer Ni(OH)2 composite thin films were fabricated and utilized for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) to simultaneously conduct electrocatalytic water splitting process. The composite thin films were deposited on Ni foam by electrodeposition technique. To find out the optimum performances of the catalysts, the first layer was fabricated with different voltages of -0.7 – -1.15 V and fixed deposition time of 2.5 min. The second layer was done with a fixed potential at -1 V and different deposition times of 1 – 3 min. The electrochemical properties and characteristics of the as-deposited composite thin films were analyzed with XRD, SEM, Raman, XPS measurements, and electrocatalytically tested with HER and OER as well as overall water splitting.
It was found that the morphology of 1st-layer Ni-Fe LDH with deposition potential at -1 V and time at 2.5 min showed as the lamellar sheets standing perpendicularly to Ni foam substrate. The first layer LDH was then electrodeposited with Ni to form a thin second layer of Ni(OH)2 which was confirmed with Raman spectroscopy analysis. The performance of the composite thin films were tested with Ni(OH)2 deposited with different deposition times. The electrochemical measurements indicated the NF3b/N2 thin film electrode exhibited the best properties for OER. With the current density of 200 mA/cm2, the overpotential and Tafel slope for oxygen evolution reaction were 257 mV and 126 mV/dec, respectively. On the other hand, the NF3b/N3 thin film electrode exhibited the best properties for HER. The best HER performance exhibited with the overpotential of -151 mV and Tafel slope of 86 mV/dec at current density of -10 mA/cm2. To show the overall water splitting process, NF3b/N2 and NF3b/N3 thin film electrodes were repectively utilized as anode and cathode with 1 M KOH as electrolyte. For the overall water splitting reaction, the electrolytic cell had the overpotantial of 1.63 V at 10 mA/cm2, while it has 348 mA/cm2 at 2.0 V. At the constant currednt test for cell stability, the cell gradually reached stable overpotential of 1.84 V at 20 mA/cm2. This work contributed to a simple electrodeposition method to fabricate double-layer composite thin film for a promising and stable electrocatalytic water splitting reaction in alkaline solution.

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