择优腐蚀制备新颖金铂异质纳米结构

发布时间：2018-05-03 20:24

  本文选题：金基异质纳米结构 + 光学性质　； 参考：《山东大学》2015年硕士论文

【摘要】：金纳米颗粒具有独特可调的光学性质,令其在光学检测、生物成像、光热治疗等很多领域内具有广阔的应用前景。该光学性质可以通过改变纳米颗粒的结构、尺寸或成分进行调控。形成异质结构是引入外来成分、改变原有结构的一种有效手段。异质结构不仅集合了单一材料的性能,同时还有不同材料有效组装后的独特性能。本文通过择优腐蚀方法得到了多种新颖的金基异质纳米结构,并对反应产物的结构和成分进行了详细的表征,通过UV-vis消光光谱对其反应过程进行了仔细的研究,对反应机制提出了较为合理的推测并加以验证。本论文的主要研究内容是：1.以金纳米棒为模板,在银离子的调控下,通过K2PtCl4对金纳米棒的侧面腐蚀反应,实现了金纳米棒光学性质的有效调控,并最终得到了哑铃状的PtAu-Au纳米棒。通过一系列对比试验发现,K2PtCl4与单质金的氧化还原反应优先发生在金纳米棒活性较高的两端。由于两端CTAB分子包覆的较少,被还原的Pt0可以沉积在两端,从而阻碍了两端的进一步反应。银离子的存在引起金纳米棒侧面的CTAB浓度升高,不利于还原出的Pto在侧面沉积,所以侧面的Au可以持续被氧化,导致金纳米棒的直径有效削减。相比较金纳米棒和核-壳纳米棒,这种新形成的较细的哑铃状Pt/Au纳米棒在对硝基苯酚的还原中,表现了更高的催化活性。这种催化活性的提高来自于哑铃状Pt/Au纳米棒的独特结构和电子效应。2.以金纳米球为模板,通过其与AgNO3、HAuCl4、K2PtCl4以及AA之间的反应,成功地制备了一种新颖的Au@PtAuAg异质纳米颗粒。通过一系列的对比试验发现,Au(Ⅲ)/Au和Ag(Ⅰ)/Ag具有较高的标准电极电势,AuAg首先在金纳米球上生长得到八面体状的Au@AuAg结构模板,随后Pt2+被AA还原,沉积在Au@AuAg纳米颗粒的顶点,而溶液中过量的HAuCl4对Au@AuAg八面体中未被Pt覆盖的区域进行腐蚀,从而得到了新颖的Au@PtAuAg异质纳米颗粒。因为Pt本身具有良好的催化性质,所以这种Au@PtAuAg异质纳米颗粒,在催化方面有着潜在的应用价值。
[Abstract]:Due to its unique and adjustable optical properties, gold nanoparticles have broad application prospects in many fields, such as optical detection, biological imaging, photothermal therapy and so on. The optical properties can be regulated by changing the structure, size or composition of nanoparticles. The formation of heterogeneous structure is an effective means to introduce foreign elements and change the original structure. Heterostructures not only aggregate the properties of a single material, but also exhibit unique properties after effective assembly of different materials. In this paper, a variety of novel gold based heterostructures were obtained by preferential etching method. The structure and composition of the products were characterized in detail, and the reaction process was studied by UV-vis extinction spectroscopy. A reasonable conjecture of the reaction mechanism was put forward and verified. The main content of this thesis is 1: 1. The optical properties of gold nanorods were effectively controlled by K2PtCl4 under the control of silver ions, and the dumbbell shaped PtAu-Au nanorods were obtained. Through a series of comparative experiments, it was found that the redox reaction of K2PtCl4 with simple gold occurred preferentially at the ends of the gold nanorods with higher activity. The reduced Pt0 can be deposited at both ends due to the less encapsulation of CTAB molecules at both ends, which hinders the further reaction at both ends. The presence of silver ions increases the concentration of CTAB on the side of the gold nanorods, which is not conducive to the deposition of the reduced Pto on the side, so the au on the side can be continuously oxidized, leading to the effective reduction of the diameter of the gold nanorods. Compared with gold nanorods and core-shell nanorods, the new dumbbell shaped Pt/Au nanorods exhibit higher catalytic activity in the reduction of p-nitrophenol. The improvement of catalytic activity comes from the unique structure and electronic effect of dumbbell Pt/Au nanorods. Using gold nanospheres as template, a novel Au@PtAuAg heterogeneous nanoparticles were successfully prepared by the reaction of Agno _ 3H _ AuCl _ 4N _ 2PtCl _ 4 with Agno _ 3H _ AuCl _ 4H _ 2PtCl _ 4 and AA. Through a series of comparative tests, it was found that au (鈪，

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