A US research team has successfully developed a new means of controlling the shape of metal nanocrystals through using a particle of platinum as a seed, it has been reported.

Headed by Peidong Yang of the University of California, the team found that by using highly-faceted cubic platinum nanocrystals as nucleation seeds and varying the conditions in the reaction solution, they were able to influence the overgrowth of a lattice matched-palladium-based compound in solution.

Specifically, it was found that the platinum cubes exhibit conformal growth on the surface area of the seeds - a process which produces platinum/palladium bimettalic core-shell structures.

Furthermore, the team discovered that by changing the amount of nitrogen dioxide in the reaction environment around the seeds they could make nanocrystals in the form of cubes, cuboctahedra and octahedra and could determine the number of surface planes.

Commenting on the scope of the research, Mr Yang told nanotechweb.org: "Such shape control enables the production of nanocrystals with specific shapes and surface types. It could therefore allow catalytic reactions with great selectivity."

The researchers also perceive that the method could be used with other materials including ruthenium, iron-platinum and cobalt platinum and that it could also be employed in magnetic and optical applications.

Source:

Nanocubes give better shaped crystals, 19/07/07
http://nanotechweb.org/articles/news/6/7/17/1

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