Site-selective growth of Ag nanocubes for sharpening their corners and edges, followed by elongation into nanobars through symmetry reduction†,Journal of Materials Chemistry C

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Site-selective growth of Ag nanocubes for sharpening their corners and edges, followed by elongation into nanobars through symmetry reduction†
Journal of Materials Chemistry C ( IF 5.7 ) Pub Date : 2018-01-01 00:00:00 , DOI: 10.1039/c7tc05625g
Shan Zhou _{1,

2,

3,

4} , David S. Mesina _{3,

4,

5,

6} , Morgan A. Organt _{4,

7,

8,

9} , Tung-Han Yang _{3,

4,

5,

6} , Xuan Yang _{3,

4,

5,

6} , Da Huo _{3,

4,

5,

6} , Ming Zhao _{1,

2,

3,

4} , Younan Xia _{1,

2,

3,

4,

5}

Affiliation

It remains a challenge to synthesize Ag nanocubes with sharp corners and edges while retaining a compact size below 20 nm. Here we demonstrate the use of site-selective growth to sharpen the corners and edges of truncated Ag nanocubes with sizes down to 18 nm, followed by their elongation into nanobars with aspect ratios up to 2. The key to the success of this synthesis is the site-selective deposition at corners and edges, as enabled by cetyltrimethylammonium chloride (CTAC). While CTA⁺ is an effective colloidal stabilizer, Cl⁻ can react with Ag⁺ to generate AgCl precipitates, slowing down the reduction kinetics. In addition, Cl⁻ can serve as a facet-selective capping agent towards the {100} side faces and thereby confine the growth mainly to corners and edges. Interestingly, once all the corners and edges have been sharpened, the growth is switched to an asymmetric mode to favor deposition on one of the six side faces only, leading to the formation of Ag nanobars with controllable aspect ratios. The symmetry reduction takes place as a result of the limited supply of Ag atoms, the strong capping of Cl⁻ ions towards the {100} facets, and the possible involvement of localized oxidative etching caused by Cl⁻/O₂. We also demonstrate that the Ag nanocubes with sharp corners and edges can serve as a better sacrificial template than their truncated counterparts in generating Au hollow nanostructures with ultrathin walls.

中文翻译：

Ag纳米立方体的定点生长以锐化其角和边缘，然后通过对称性降低伸长成纳米棒†

合成具有尖角和边缘的Ag纳米立方体，同时保持小于20 nm的紧凑尺寸仍然是一个挑战。在这里，我们演示了使用位点选择性生长来锐化尺寸小于18 nm的截短的Ag纳米立方体的角和边缘，然后将其伸长成纵横比最大为2的纳米棒。十六烷基三甲基氯化铵（CTAC）可以在角落和边缘进行定点沉积。而CTA ⁺是一种有效的胶体稳定剂，氯^-可以与银发生反应⁺，以产生氯化银沉淀物，减慢还原动力学。此外，氯^-可以用作朝向{100}侧面的面选择性封盖剂，从而将生长主要限制在拐角和边缘。有趣的是，一旦所有角和边缘都变尖了，就将生长切换为不对称模式，仅在六个侧面之一上进行沉积，从而形成长宽比可控的Ag纳米棒。对称还原发生的Ag原子，氯的强覆盖的有限供应的结果^-离子向{100}面，并且局部氧化的可能参与蚀刻经Cl引起^- / O ₂。我们还证明，在生成具有超薄壁的金空心纳米结构时，具有尖角和边缘的Ag纳米立方体可以比其截短的同行更好地用作牺牲模板。

更新日期：2018-01-01

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