所謂的「自催化反應」就是透過金離子(Au+)在金奈米材料表面上，不需要額外的還原劑，就可以在材料表面上自發性的還原為金原子，進而堆積成體積增大的金奈米粒子。本次的研究首要主要目的為首先製備雙金屬奈米材料及雙金屬奈米合金材料，再進行「自催化反應」，再利用紫外光/可見光光譜儀和穿透式電子顯微鏡去觀察兩種材料在「自催化反應」中的生長機制路徑。在雙金屬奈米合金的「自催化反應」中，不管是固定雙金屬奈米合金的劑量或是生長試劑的劑量，都可以發現到會產生「紅移現象」，會使整體的尺寸變大以便得到更大的吸收波長；不過當雙金屬奈米粒子在進行「自催化反應」後，發現到所展現的成果與推測的結論也有所不同並且反應過程中不只存在「自催化反應」，同時也可以發現到有「加凡尼反應」的出現，在紫外光/可見光光譜中，雙金屬奈米粒子中的銀奈米的特徵吸收峰消失了(406 nm)，在吸收波長接近 550nm 位置有新的特徵吸收峰出現並伴隨著生長試劑添加的越多，「紅移現象」也愈發的明顯，位移幅度也愈發的大；再著，去探討銀奈米粒子及模擬雙金屬奈米粒子之系統
(Au NPs+Ag NPs)各別添加不同濃度的生長試劑使用紫外光/可見光光譜儀和穿透式電子顯微鏡進而去觀察、探討在發生了「加凡尼反應」下，「自催化反應」及「紅移現象」是否也會相繼的發生，最後再利用紫外光/可見光光譜儀去觀察雙金屬奈米粒子、銀奈米粒子及模擬雙金屬奈米粒子之系統(Au NPs+Ag NPs)添加不同濃度的生長試劑後的每分鐘之生長時間路徑。
The “self-catalytic reaction” refers to the spontaneous reduction of gold ions (Au+) on the surface of gold nanomaterials without the need for additional reducing agents.This process leads to the autonomous reduction of gold ions into gold atoms, subsequently accumulating into larger size gold nanoparticles. The primary objective of this study is to first prepare Au/Ag alloy nanoparticles and Au/Ag bimetal nanoparticles, followed by conducting the self-catalytic reaction. The growth mechanisms of these two materials during the self-catalytic reaction are then observed visible spectrometer and transmission electron microscope (TEM).In the self-catalytic reaction of Au/Ag alloy nanoparticles,results showed that Au/Ag alloy nanoparticles reacting with growth reagent resulted in red shift of original characteristic absorption of Au/Ag alloy nanoparticles. This phenomenon is due to the increased particle size and then obtain a longer absorption wavelength.However, the self-catalytic reaction of Au/Ag alloy nanoparticles showed that self-catalytic reaction and galvanic reaction occurred at the same time. Seen in the results of absorption spectra of Au/Ag bimetal nanoparticles, the characteristic absorption peak (406 nm) of Au/Ag bimetal nanoparticles disappears and a new characteristic absorption peak appear near the 550nm. With an increase in the amount of growth reagent, the new appeared absorption peak has large red shift. This result indicated the mechanism of Au/Ag bimetal nanoparticles was different from Au/Ag alloy nanoparticles. Because of no previous studies have similar experiments until now. To clearly understand the growth mechanism of Au/Ag bimetal nanocompoaites, the study explores the mixture of Au and Ag NPs to simulate Au/Ag bimetal nanocompoaites and Ag NPs alone to observe galvanic reaction. Finally, to get more information of self-catalytic reaction of Au/Ag alloy and bimetal nanoparticles, UV-visible spectrum is utilized to trace and observe the absorption spectra of bimetallic nanoparticles, silver nanoparticles, and the simulated bimetallic nanoparticles system (Au NPs + Ag NPs) at different time points after the addition of growth reagent.
