| 摘要: | 為因應全球淨零碳排放趨勢，尋求可再生能源來解決能源危機和環境問題是首要辦法。其中，氫能因具有高能量密度與低碳排等特色，被視為傳統高汙染產業的重要替代能源。然而，水電解製氫因為在過程中沒有二氧化碳的排放，是近幾年主要用來生產氫氣的方式之一，但受昂貴的催化劑價格與高過電位影響，限制了氫氣的製備效率和可行性。為了解決這些問題，本研究致力於開發低成本的過渡金屬催化劑來取代貴金屬催化劑，材料的選擇上，以具有高催化活性與適當氫吸附能的鎳及銅金屬，透過金屬合金化的方式，在三維結構的碳纖維氈基材上，通過一步驟電沉積來合成鎳銅合金複合材料，並進一步將催化材料應用於水電解產氫。
本研究在無外加水(0 wt.%)及不同比例外加水(1 wt.%、3 wt.%以及5 wt.%)之氯化膽鹼/乙二醇深共熔系統中，進行恆電位電沉積。實驗中，分別在-1.5 V(V vs Ag/AgCl sat, KCl)及-2V(V vs Ag/AgCl sat, KCl)的電壓下進行材料的製備。從結果發現，在深共熔系統中添加額外水，除有助於使得沉積結構更均勻外，對於鎳銅合金比例也具調控性。其中，以-2NiCu(3)/CF複合材料在1.0 M KOH溶液中表現出最優異的析氫(27 mV@10 mA/cm2)與析氧(390 mV@50 mA/cm2)過電位表現，透過金屬間的協同作用以及添加水導致的更細緻結構，有助於活性位點數量的提升，對於催化性能產生直接影響。另外，該複合材料在長時間的水電解產氫也展現優異的穩定性，水電解電壓達1.52 V，優於商業上常見之水電解槽，代表在含微量水的深共熔系統中製備雙功用電催化劑，是相當有潛力的做法，這將對於綠氫的生產提供更多的選擇性。
;Energy is a crucial element in modern daily life and has a significant impact on our future. Hydrogen, a clean-burning fuel, can be produced from various sources and applied in multiple industries, such as transportation and power generation. Water electrolysis, using electricity to split water molecules into hydrogen and oxygen, is an environmentally friendly method to produce pure hydrogen. However, there are still obstacles to overcome, such as the high drive voltage and high cost of production. Transition metal-based materials are regarded as a potential solution to this issue due to their cost-effectiveness and high catalytic activity for water electrolysis, as suggested by many studies. Our research proposes a one-step electrodeposition method in a choline chloride/ethylene glycol deep eutectic solvent (ChCl/EG DES) with varying water content to fabricate nickel-copper alloy/carbon fiber felt composite electrodes for water splitting.
Based on the materials analysis, it can be confirmed through XRD, SEM, and XPS analyses that the Nickel-Copper alloy can be effectively synthesized using the water-containing DES system. The catalyst electrode synthesized at -2 V in ChCl/EG with 3 wt.% water exhibits an excellcent hydrogen evolution (HER) overpotential (27 mV@10 mA/cm2) in 1.0 M KOH solution, outperforming previously reported values. The smaller charge transfer impedance and Tafel slope indicate that the Nickel-Copper alloy/CF electrode has high electron transport efficiency, which facilitates chemical reactions. In addition, the stability of the electrode is confirmed by a 12 hour chronopotentiometry test, and the overall water splitting voltage obtained by the stability test is lower than that of commercial devices, indicating that the composite electrode has the potential to replace commercial catalysts. Its outstanding catalytic performance proves that the one-step electrodeposition in the water-containing DES system is a feasible method for synthesizing composite electrodes. |
