Activation of specific sites on cubic nanocrystals: a new pathway for controlled epitaxial growth towards catalytic applications

A method has been developed for controlled epitaxial growth on cubic nanocrystals by selectively activating their surface via etching. For example, it produces Pd concave nanocubes via seeding growth on their corners and edges, and in turn, formulates highly active sites for catalysis. This method offers a better capability of preventing atomic addition on undesired locations and maintaining particle size in the seeding process, as compared with the previous technique. With the particle size well maintained, the products fully exhibit superior electrocatalytic performance enabled by active sites and high-index facets in formic acid oxidation. Another contribution of this work is to enable the growth of a noble metal with high catalytic activities on another type of cheaper metal, which greatly reduces the usage of expensive materials while retaining high catalytic activity. In this article, we have demonstrated the deposition of a very limited amount of Pt (only 3.3 wt%) on Pd nanocrystals towards high electrocatalytic activities in an oxygen reduction reaction. Preliminary studies demonstrate that the synthetic strategy can be also applied to the controllable deposition of a different material on the faces of a nanocrystal by simply altering surface conditions.