Advertisement

If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.

ENJOY UNLIMITED ACCES TO C&EN

Materials

Bimetal Nanocube Siding

Researchers control reaction kinetics to grow silver-palladium particles with specific structures

by Lauren K. Wolf
December 19, 2011 | A version of this story appeared in Volume 89, Issue 51

[+]Enlarge
Credit: Angew. Chem. Int. Ed.
The nature of silver-palladium nanocrystals varies, depending on the rate at which silver is added.
Researchers can form bimetallic nanocrystals of various shapes by controlling the rate at which one metal is added to “seed” particles of another metal.
Credit: Angew. Chem. Int. Ed.
The nature of silver-palladium nanocrystals varies, depending on the rate at which silver is added.

By adjusting the rate at which silver nitrate is added to a solution containing palladium nanocubes, materials scientists can precisely control whether silver atoms stick to and grow on one, three, or all six sides of the cubes (Angew. Chem. Int. Ed., DOI: 10.1002/anie.201107061). Such bimetallic nanocrystals are of interest for their use in photonics and as tandem catalysts. At slow AgNO3 addition rates, Younan Xia of Washington University in St. Louis and coworkers obtained palladium nanocubes with silver attached to one side. At moderate rates, silver deposited on three adjacent sides of the cubes, and at fast rates, silver formed a shell around the palladium cubes by adhering to all six sides. Xia says this deposition selectivity occurs because of supply and demand: At slow AgNO3 addition rates, the concentration of silver is so low that nucleation and growth are limited to one side of the cubes. At moderate rates, the nucleation can spread to adjacent sides, and at fast rates, it’s unlimited. Bimetallic nanocrystals may be fabricated by other methods, Xia says, but this one is the first to “precisely control the sites at which heterogeneous nucleation and growth are initiated.” The approach should be applicable to other bimetallic systems, he adds.

Article:

This article has been sent to the following recipient:

0 /1 FREE ARTICLES LEFT THIS MONTH Remaining
Chemistry matters. Join us to get the news you need.