ChemInform Abstract: 25th Anniversary Article: Galvanic Replacement: A Simple and Versatile Route to Hollow Nanostructures with Tunable and Well-Controlled Properties

The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, 30332, USA.
Advanced Materials (Impact Factor: 17.49). 01/2014; 25(44). DOI: 10.1002/adma.201302820
Source: PubMed


This article provides a progress report on the use of galvanic replacement for generating complex hollow nanostructures with tunable and well-controlled properties. We begin with a brief account of the mechanistic understanding of galvanic replacement, specifically focused on its ability to engineer the properties of metal nanostructures in terms of size, composition, structure, shape, and morphology. We then discuss a number of important concepts involved in galvanic replacement, including the facet selectivity involved in the dissolution and deposition of metals, the impacts of alloying and dealloying on the structure and morphology of the final products, and methods for promoting or preventing a galvanic replacement reaction. We also illustrate how the capability of galvanic replacement can be enhanced to fabricate nanomaterials with complex structures and/or compositions by coupling with other processes such as co-reduction and the Kirkendall effect. Finally, we highlight the use of such novel metal nanostructures fabricated via galvanic replacement for applications ranging from catalysis to plasmonics and biomedical research, and conclude with remarks on prospective future directions.

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    • "At this point the structure has also developed a single large opening at its base. This is followed by a progression which transforms the structure into a nanocage [1], a designation attributed to hollow structures with a geometric pattern of openings over their surface (Figs. 2(g) and 2(h)). "
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    ABSTRACT: The sacrificial templates used in galvanic replacement reactions dictate the properties of the hollow metal nanostructures formed. Here, we demonstrate that substrate-based Au-Ag nanoshells with radically altered properties are obtained by merely coating silver templates with an ultrathin layer of gold prior to their insertion into the reaction vessel. The so-formed nanoshells exhibit much smoother surfaces, a higher degree of crystallinity and are far more robust. Dealloying the nanoshells results in the first demonstration of substrate-based nanocages. Such cages exhibit a well-defined pattern of geometric openings in directions corresponding to the {111}-facets of the starting template material. The ability to engineer the cage geometry through adjustments to the orientational relationship between the crystal structure of the starting template and that of underlying substrate is demonstrated. Together these discoveries provide the framework to advance our understanding of the mechanisms governing substratebased galvanic replacement reactions.
    Nano Research 03/2014; DOI:10.1007/s12274-013-0402-y · 7.01 Impact Factor
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    ABSTRACT: Sn hollow nanospheres (HNSs) were prepared by galvanic replacement, employing Ni nanospheres (NSs)as templates. The formation process and electrochemical performance of Sn HNS were studied. The Sn HNS resulted in better stability and electrochemical performance when used as an anode material in lithium-ion batteries. The Sn HNS electrode retained a good reversible capacity of 516.1 mAh g-1after 50 cycles at a current density of 100 mAh g-1, which was much higher than that of Sn NS (128 mAh g-1).TEM images of the Sn HNSs after 50 cycles indicated that the volume expansion outside the spheres had been alleviated, and the aggregation between the active materials had been prevented.
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    Nano Research 01/2014; 8(1):271-280. DOI:10.1007/s12274-014-0664-z · 7.01 Impact Factor
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