樹枝狀金觸媒在燃料電池的應用

Abstract

除了商用多晶金電極，我們以脈衝式電鍍沉積法，在玻璃碳電極的表面上沉積出具有很好的結晶性，並呈現三軸對稱的樹狀金電極。而我們利用不同的沉積時間製備出不同條件的金電極，如: GD3000s、GD1500s及NP500s。 首先，將製備出不同條件的金電極與商用多晶金電極在0.5 M KOH中進行L-cysteine還原脫附與在0.5 M H2SO4中進行金表面單層氧化物還原脫附的反應，用公式:Q_a/Q_b 來討論Au(111)面在四個不同條件的金電極上分別占的比例對電催化的影響。接著，將不同條件的電極進行甲醇、乙醇、甲酸以及氧氣的催化反應。相較於其他條件的金電極，GD3000s對於甲醇、乙醇及甲酸的電催化效果皆有較好表現。相反的，因顆粒大小的因素，導致GD3000s對於氧氣的電催化效果較其他條件的電極差。 最後，我們以相同的方式在玻璃碳電極上製備出具有良好結晶性的樹狀銀電極。以便於日後研究樹狀金、銀電及之間的活性差異。

關鍵字:樹狀金電極、甲醇電氧化、乙醇電氧化、甲酸電氧化、氧氣還原、樹狀銀電極Apart from the commercial polycrystalline gold electrode, we used pulsed current electrolysis to deposit gold dendrite showing well crystalline and three-order symmetry on the surface of the glassy carbon electrode (GC). And we used different deposition durations to prepare the gold electrodes (GD3000s, GD1500s, and NP500s). First, we carried out the reductive desorption of L-cysteine on gold electrodes prepared by different deposition times and commercial polycrystalline gold electrode in 0.5M KOH and desorbed the monolayer oxide on gold surface in 0.5M H2SO4. Following, we used the ratio: Q_a/Q_b to evaluate the effect of an Au(111) facet on the four different gold electrodes in electrocatalysis. We then performed the electrocatalysis reaction with methanol, ethanol, formic acid, and oxygen. Of all the electrodes tested, GD3000s showed the best performance in the electrocatalysis reaction with methanol, ethanol, and formic acid. However, due to its larger particle size, GD3000s exhibited poor electrocatalytic activity of oxygen reduction reaction. Finally, we prepared the silver dendrite on glassy carbon with good crystalline structure by the same means, in order to study the difference between gold dendrite and silver dendrite.

Keyword: gold dendrites、methanol electro-oxidation、ethanol electro-oxidation、formic acid electro-oxidation、oxygen reduction、silver dendrites.