Separating Growth from Nucleation for Facile Control over the Size and Shape of Palladium Nanocrystals.

In order to maximize the performance of nanocrystals in a specific application, it is necessary to control both their size and shape. Here we report a one-pot protocol that allows us to separate growth from nucleation for achieving better controls over the size and shape of Pd nanocrystals. The two processes are temporally separated from each other, although the synthesis is carried out in the same reaction container. Size control is achieved by simply varying the ratio between the amounts of precursor allocated to the growth and nucleation processes. With the involvement of seeds at a fixed number, increasing the amount of precursor for growth leads to increasingly larger nanocrystals. Shape control is made possible by varying the capping agent, with bromide leading to a cubic shape and citrate inducing the formation of an octahedral shape. The synthesis can also be scaled up by at least 10-fold without compromising the quality.