Electrodeposition of alloy PtPd nanocrystals with shape transforming from low–index facet to high–index facet

Abstract

High–efficient Pt–based electrocatalyst played important role in fuel cell reaction. Shape–controlled synthesis and alloying are two widely used method to optimize electro–catalytic performance of nanoparticles. In this work, we have successfully synthesized shaped PtPd alloy nanocrystals with high–index facet as well as low–index facet via square wave potential (SWP) procedure. The shape transformation from low–index facet to high–index facet could be easily achieved by simply adjusting the parameter of SWP procedure. The periodic adsorption and desorption of hydrogenated or oxygenated species played a key role in the shape–controlled synthesis of PtPd alloy nanocrystals during the process of synthesis. Compared with commercial Pt/C, the prepared PtPd nanocrystals showed great electrocatalytic performance for ethylene glycol oxidation reaction (EGOR). The peak current densities of PtPd convex tetrahexahedral (THH) nanocrystals and PtPd concave nanocubes (NCs) were 21.5 mA ∙ cm−2 and 16.5 mA ∙ cm−2, which were 11.9 and 9.2 times higher than that of commercial Pt/C, respectively. The PtPd alloy nanocrystals also showed much better stability compared with commercial Pt/C. The excellent electro–catalytic performance could attribute to the surface structure and effect of alloying.