Chemistry

Nanoparticle transformations in 3D

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Science  30 May 2014:
Vol. 344, Issue 6187, pp. 985
DOI: 10.1126/science.344.6187.985-f

A golden nanoparticle framework.

PHOTO: B. GORIS ET AL., NANO LETTERS (5 MAY 2014) © 2014 AMERICAN CHEMICAL SOCIETY

When silver nanocubes react with gold ions, they combine into hollow-frame octohedral structures. Now Goris et al. have imaged the process with electron tomography and x-ray element mapping to see how it happens. Goris et al. reacted silver nanocubes with HAuCl4 and found that three silver atoms were oxidized for every gold atom consumed. They removed a series of samples at different points in the reaction and used three-dimensional (3D) tomography to see the steps. First, a pinhole opens up in one facet. Next, all the facets open up. Then the vertices flatten to become new facets, until finally only an octahedral wire frame structure remains. The analysis also revealed that a protective gold layer surrounded the initial pinhole and forced the reaction of silver from the interior of the nanocube.

Nano Lett. 10.1021/nl500593j (2014).

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