Conformal deposition of platinum as ultrathin shells on facet-controlled palladium nanocrystals offers a great opportunity to enhance the catalytic performance while reducing its loading. Here we report such a system based on palladium icosahedra. Owing to lateral confinement imposed by twin boundaries and thus vertical relaxation only, the platinum overlayers evolve into a corrugated structure under compressive strain. For the core-shell nanocrystals with an average of 2.7 platinum overlayers, their specific and platinum mass activities towards oxygen reduction are enhanced by eight- and sevenfold, respectively, relative to a commercial catalyst. Density functional theory calculations indicate that the enhancement can be attributed to the weakened binding of hydroxyl to the compressed platinum surface supported on palladium. After 10,000 testing cycles, the mass activity of the core-shell nanocrystals is still four times higher than the commercial catalyst. These results demonstrate an effective approach to the development of electrocatalysts with greatly enhanced activity and durability.

中文翻译：

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钯-铂核-壳二十面体具有显着增强的活性和对氧还原的耐久性。

铂作为超薄壳的共形沉积在受面控制的钯纳米晶体上提供了一个绝佳的机会来增强催化性能，同时降低其负载量。在这里，我们报告基于钯二十碳六烯的这种系统。由于由双边界施加的侧向限制以及因此仅垂直的松弛，铂覆盖层在压缩应变下演变成波纹状结构。对于平均具有2.7个铂覆盖层的核-壳纳米晶体而言，其相对于氧还原的比活性和铂质量活性相对于市售催化剂分别提高了8倍和7倍。密度泛函理论计算表明，这种增强可以归因于羟基与负载在钯上的压缩铂表面结合力的减弱。10点以后 在000个测试循环中，核-壳纳米晶体的质量活性仍比市售催化剂高四倍。这些结果证明了开发具有大大增强的活性和耐久性的电催化剂的有效方法。