Galvanic replacement of intermetallic nanocrystals as a route toward complex heterostructures,Nanoscale

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Galvanic replacement of intermetallic nanocrystals as a route toward complex heterostructures
Nanoscale ( IF 5.8 ) Pub Date : 2021-1-25 , DOI: 10.1039/d0nr08255d
Alexander N. Chen _{1,

2,

3,

4} , Emma J. Endres _{1,

2,

3,

4} , Hannah M. Ashberry _{1,

2,

3,

4} , Sandra L. A. Bueno _{1,

2,

3,

4} , Yifan Chen _{1,

2,

3,

4} , Sara E. Skrabalak _{1,

2,

3,

4}

Affiliation

Galvanic replacement reactions are a reliable method for transforming monometallic nanotemplates into bimetallic products with complex nanoscale architectures. When replacing bimetallic nanotemplates, even more complex multimetallic products can be made, with final nanocrystal shapes and architectures depending on multiple processes, including Ostwald ripening and the Kirkendall effect. Galvanic replacement, therefore, is a promising tool in increasing the architectural complexity of multimetallic templates, especially if we can identify and control the relevant processes in a given system and apply them more broadly. Here, we study the transformation of intermetallic PdCu nanoparticles in the presence of HAuCl₄ and H₂PtCl₆, both of which are capable of oxidizing both Pd and Cu. Replacement products consistently lost Cu more quickly than Pd, preserved the crystal structure of the original intermetallic template, and grew a new phase on the sacrificial template. In this way, atomic and nanometer-scale architectures are integrated within individual nanocrystals. Product morphologies included faceting of the original spherical particles as well as formation of core@shell and Janus-style particles. These variations are rationalized in terms of differing diffusion behaviors. Overall, galvanic replacement of multimetallic templates is shown to be a route toward increasingly exotic particle architectures with control exerted on both Angstrom and nanometer-scale features, while inviting further consideration of template and oxidant choices.

中文翻译：

金属间纳米晶体的电化学取代是通往复杂异质结构的途径

电取代反应是将单金属纳米模板转化为具有复杂纳米级结构的双金属产品的可靠方法。当替换双金属纳米模板时，甚至可以制造更复杂的多金属产品，最终纳米晶体的形状和结构取决于多种过程，包括奥斯特瓦尔德熟化和柯肯达尔效应。因此，电流置换是增加多金属模板的体系结构复杂性的有前途的工具，尤其是当我们可以识别和控制给定系统中的相关过程并更广泛地应用它们时。在这里，我们研究在HAuCl ₄和H ₂ PtCl ₆存在下金属间PdCu纳米颗粒的转变，它们都能够氧化Pd和Cu。替代产品始终比Pd更快地损失Cu，保留了原始金属间模板的晶体结构，并在牺牲模板上形成了新的相。这样，原子级和纳米级的体系结构被整合到单个纳米晶体中。产品形态包括原始球形颗粒的刻面以及核壳和Janus型颗粒的形成。这些变化根据不同的扩散行为而合理化。总体而言，多金属模板的电镀取代被证明是通向越来越稀奇的粒子体系结构的一种途径，同时对埃和纳米尺度的特征都施加了控制权，同时还需要进一步考虑模板和氧化剂的选择。

更新日期：2021-01-25

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