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小木虫论坛-学术科研互动平台 » 材料区 » 微米和纳米 » 合成表征 » 金纳米棒的合成
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songjuan322

木虫 (小有名气)

[求助] 金纳米棒的合成 已有1人参与

求助求助！希望各位大神能帮帮我！
     最近在合成金纳米棒，但是做了很多次试验，得到的金纳米棒都是紫色或者偏蓝色的，吸收波长在600-700 nm处，NaBH4 和抗坏血酸都是新配置的溶液
参考文献“Improved Size-Tunable Synthesis of Monodisperse Gold Nanorods through the Use of Aromatic Additives” Christopher B. Murray*
Synthesis of Gold NRs.
The seed solution for gold NRs was prepared as reported previously. A 5 mL amount of 0.5 mM HAuCl4 was mixed with 5 mL of 0.2 M CTAB solution. A 0.6 mL portion of fresh 0.01 M NaBH4 was diluted to 1 mL with water and was then injected into the Au(III)CTAB solution under vigorous stirring (1200 rpm). The solution color changed from yellow to brownish-yellow, and the stirring was stopped after 2 min. The seed solution was aged at room temperature for
30 min before use. （这部还原剂是快速加入的，大力匀速搅拌，种子液是茶色的）

To prepare the growth solution,
9.0 g of CTAB together with defined amounts of additives (Table S1)（这里我用的是1.1g 5-溴水杨酸） were dissolved in 250 mL of warm water (50－70 度, depending on the additive) in a 500 mL Erlenmeyer flask. The solution was allowed to cool to 30 C, when a 4 mM AgNO3 solution, as detailed in Table S1（12 mL）, was added. The mixture was kept undisturbed at 30 C for15 min, after which 250 mL of 1 mM HAuCl4 solution and, if necessary, a small amount of HCl (37 wt % in water, 12.1 M) was added. (这部没有加，因为根据文献中所说，我需要的颗粒小于850nm,不需要加)。 After 15 min of slow stirring (400 rpm), 0.064 M ascorbic acid (Table S1) （2 mL）was added, and the solution was vigorously stirred for 30 s until it became colorless. The growth solution had a CTAB concentration of about 0.05 M and was used right after preparation. Finally, 0.8 mL of seed solution was injected into the growth solution. The resultant mixture was stirred for 30 s and left undisturbed at 30 C for 12 h for NR growth. The reaction products were isolated by centrifugation at 8500 rpm for 25 min followed by removal of the supernatant. The precipitates were redispersed in 10 mL of water.

不知道哪里出了问题，我想合成的是800nm左右的，
多次重复试验均是这个结果，后面调大硝酸银的浓度，合成出来的还是紫色的，不知道哪里出了问题。

另外我按照 El-Sayed* “Preparation and Growth Mechanism of Gold Nanorods (NRs) Using Seed-Mediated Growth Method”中的方法合成，
“Growth of NRs with Plasmon Bands Less Than 850 nm.
CTAB (5 mL, 0.20 M) was added to (0.050, 0.10, 0.15, 0.20, 0.25 mL) (根据我的粒径要求，这里选择的是0.2.ml) of 0.0040 M AgNO3 solution at 25 °C. To this solution, 5.0 mL of 0.0010 M HAuCl4 was added, and after gentle mixing of the solution 70 μL of 0.0788 M ascorbic acid was added. Ascorbic acid as a mild reducing agent changes the growth solution from dark yellow to colorless. It is worth noting that the five growth solutions above are identical except for their silver ion content. The final step was the addition of 12 μL of the seed solution to the growth solution at 27-30 °C. The color of the solution gradually changed within 10-20 min. For longer NRs, the color change takes place more slowly. The temperature of the growth medium was kept constant at 27-30 °C in all the experiments. This pathway produces pure NR solutions with aspect ratios up to 4.7.”
可是合成出来的还是紫色的，不知道哪里出了问题，重复试验还是这个现象。希望大神们帮帮忙！万分感谢！

金纳米棒的合成
金纳米种子.jpg


金纳米棒的合成-1
2.jpg


金纳米棒的合成-2
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1楼 2016-05-31 10:58:38
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zihua886

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songjuan322: 金币+50, ★★★很有帮助 2016-06-01 14:11:15
引用回帖:
8楼: Originally posted by songjuan322 at 2016-06-01 09:20:26
这个都注意到了！...

反正你这个种子和棒的颜色都不太对，产物里面有肯定有很多球和其他形貌。那个深紫色的样品偏浑浊，肯定有较多大颗粒的粒子；浅兰色的样品够清澈，但是颜色太浅，产物里面应该有较多锥状和三角片之类杂质形貌。这些都说明，要么是种子出问题了，要么是生长液的条件不对，有很大可能是CTAB和还原剂的问题。
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9楼2016-06-01 10:55:54
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zihua886

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感谢参与，应助指数 +1
songjuan322: 金币+50 2016-05-31 20:22:21
你这种子的颜色有点不对。应该是深棕黄色，而不是茶色的。是不是冬天拍的照片？
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songjuan322
工作原因，暂离数月。
2楼2016-05-31 14:14:33
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huangxin2011

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感谢参与，应助指数 +1
直接买现成的，省时省力。
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3楼2016-05-31 14:21:02
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songjuan322

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引用回帖:
2楼: Originally posted by zihua886 at 2016-05-31 14:14:33
你这种子的颜色有点不对。应该是深棕黄色，而不是茶色的。是不是冬天拍的照片？

最近才拍的，那是不是我的种子合成有问题？是将ctab加入到氯金酸，还是相反，还原剂需要快速加入吗？请教！！！非常感谢
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4楼2016-05-31 15:29:14
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