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Copy from NatureChina: http://www.nature.com/nchina/2007/070523/full/nchina.2007.89.html.

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• Materials
• Chemistry

Published online: 23 May 2007 | doi:10.1038/nchina.2007.89

Nanocrystals: The more the better
Wei Zeng

Tetrahexahedral platinum nanocrystals can be synthesized using an electrochemical method

Original article citation
Tian, N., Zhou, Z. Y., Sun, S. G., Ding, Y. & Wang, Z. L. Synthesis of tetrahexahedral platinum nanocrystals with high-index facets and high electro-oxidation activity. Science 316, 732–735 (2007).
Introduction © (2007) AAAS

The catalytic performance of nanocrystals can be enhanced by increasing their number of facets (flat faces). It is, however, rather difficult to synthesize nanocrystals with many facets because of their high surface energy. Now, Shigang Sun, Zhonglin Wang and co-workers1 have produced tetrahexahedral (24 facets) platinum nanocrystals of high purity using an electrochemical method that has a high yield and is cost efficient.
Platinum nanospheres, 750 nm in size, are deposited onto a 'glassy carbon' electrode in a standard three-electrode cell. When a square-wave potential is applied to the glassy carbon, small tetrahexahedral nanocrystals begin to grow on the electrode surface at the expense of the larger nanospheres. By varying the operation conditions, nanocrystals with sizes from 20 nm to 240 nm were achieved.
Tetrahexahedral crystals occasionally exist in nature in fluorite and diamond, but very rarely in metals. The surfaces of these platinum nanocrystals are not only chemically and thermally stable (up to 800 ºC), but they also enhance catalytic activity for electro-oxidation of small organic fuels up to four times as much as bulk platinum. In addition, they can be used in a wide range of applications, including car converters and gas sensors.
The authors in this work are from:
State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China; School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA.

References

• Tian, N., Zhou, Z. Y., Sun, S. G., Ding, Y. & Wang, Z. L. Synthesis of tetrahexahedral platinum nanocrystals with high-index facets and high electro-oxidation activity. Science 316, 732–735 (2007).  | Article | PubMed | ChemPort |

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