Nanocrystal shape control

The shape of metal nanocrystals can be accurately controlled by using a small particle of a different metal as a seed.
Peidong Yang and co-authors reacted a platinum nanocube (~13 nanometres each side) with a palladium-based compound to produce core–shell Pt/Pd nanocrystals. By varying the reaction environment, and in particular the amount of NO2, the researchers were able to obtain three different shapes — cubes, cuboctahedra and octahedra.
Many of the physical and chemical properties of nanocrystals depend strongly on their morphology. The authors show, for example, that the catalytic activity of the cubes is quite different from that of the other two types of nanocrystals. The use of seeds represents a clear step towards the development of nanocrystals with well-defined shapes.
Author contact:
Peidong Yang (University of California, Berkley, CA, USA)
Tel: +1 510 643 1545; E-mail: p_yang@berkeley.edu