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 $\bullet$ cm⁻² and 16.5 mA $\bullet$ 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.

高效铂基电催化剂在燃料电池反应中发挥了重要作用。形状控制合成和合金化是优化纳米粒子电催化性能的两种广泛使用的方法。在这项工作中，我们通过方波电位（SWP）程序成功地合成了具有高折射率晶面和低折射率晶面的成形 PtPd 合金纳米晶体。通过简单地调整 SWP 程序的参数，可以很容易地实现从低指数小平面到高指数小平面的形状转换。在合成过程中，氢化或氧化物质的周期性吸附和解吸在 PtPd 合金纳米晶体的形状控制合成中起着关键作用。与商业 Pt/C 相比，制备的 PtPd 纳米晶体对乙二醇氧化反应 (EGOR) 表现出良好的电催化性能。PtPd凸四面体（THH）纳米晶体和PtPd凹纳米立方体（NCs）的峰值电流密度为21.5 mA $\bullet$ cm ^-2和 16.5 mA $\bullet$ cm ^-2，分别是商业 Pt/C 的 11.9 倍和 9.2 倍。与商业 Pt/C 相比，PtPd 合金纳米晶体也表现出更好的稳定性。优异的电催化性能可归因于合金化的表面结构和效果。