氧化還原置換合成三元金屬奈米材料與光催化的應用

Abstract

以金奈米雙三角錐(Gold Nanobipyramids, AuNBPs)與金奈米棒(Gold Nanorod, AuNRs)兩種材料在Hexadecyltrimethylammonium chloride(CTAC)環境中將銀離子還原在表面，以至表面生長銀後形成棒狀及塊狀的金/銀-核/殼的結構，接著以銀做為媒介，利用氧化還原電位的差異，將金、鈀、鉑進行對銀的賈法尼置換(Galvanic replacement reaction)，並研究各材料與各金屬之間置換後在構型上的差異及光譜上的變化。由於實驗所使用的三價金與四價鉑皆為高價數金屬，導致大量的銀被置換後只能換上少量的金及鉑，進而使其外部構型不甚堅固，因此實驗中我們利用Sodium oleate(NaOL) 先將三價的金先行還原成一價的金，再與二價的鉑一同進行不同價數的相同金屬對同一材料進行置換，讓等量的銀可以置換上較多的金及鉑，使其結構達到更加穩固之目的。最後嘗試將此種材料應用在光電催化實驗上，如產氫反應及二氧化碳還原反應。

We reduce the silver ion on Gold nanobipyramids (AuNBPs) and Gold nanorods (AuNRs) these two nanomaterials in Hexadecyltrimethylammonium chloride (CTAC). Ag overgrowth on the AuNBPs/AuNRs and spherical Au nanoparticles form Au/Ag heteronanorods/nanocuboids and (Au core)@(Ag shell), respectively. Because of the different oxidation-reduction potential, we can change the silver atom into silver ion and reduce the other metal (like: gold, palladium and platinum) on the gold nanobipyramids and gold nanorods. Then we can research the different structure in these materials. Because some of the metal we used have high valence number, a large amount of silver can be replaced with a little amount of gold or platinum after being replaced and the structure isn’t stable enough. To solve the problem, we use Sodium oleate (NaOL) to reduce Au(III) into Au(I). Then we use the Au(I) and Pt(II) to replace the silver. So that the same amount of silver can replace more gold and platinum. To make its structure more stable. Then we try to use these nanomaterials on photocatalytic application,.like hydrogen evolution reaction (HER) and carbon dioxide reduction reaction (CO2RR).