Owing to the presence of {111} facets, twin boundaries, and strain fields on the surface, noble-metal nanocrystals with an icosahedral shape have been reported with stellar performance toward an array of catalytic reactions. Here, we report the successful synthesis of Ru icosahedral nanocages with a face-centered cubic (fcc) structure by conformally coating Pd icosahedral seeds with ultrathin Ru shells, followed by selective removal of the Pd cores via chemical etching. We discovered that the presence of bromide ions was critical to the layer-by-layer deposition of Ru atoms. According to in situ XRD, the fcc structure in the Ru nanocages could be retained up to 300 °C before it was transformed into the conventional hexagonal close-packed (hcp) structure. Additionally, the icosahedral shape of the Ru nanocages could be largely preserved up to 300 °C. The Ru icosahedral nanocages with twin boundaries on the surface exhibited greatly enhanced activities toward both the reduction of 4-nitrophenol and decomposition of hydrazine than their cubic and octahedral counterparts. When benchmarked against the parental [email protected] core–shell nanocrystals, all the Ru nanocages displayed superior catalytic activities. First-principles density functional theory calculations also suggest that the fcc-Ru icosahedral nanocages containing residual Pd atoms are more promising than the conventional hcp-Ru solid nanoparticles in catalyzing nitrogen reduction for ammonia synthesis. With the subsurface impurities of Pd, the twin boundary regions of the icosahedral nanocages are able to stabilize the N₂ dissociation transition state, reducing the overall reaction barrier and promoting the competition with the N₂ desorption process.

中文翻译：

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具有面心立方结构的钌二十面体纳米笼的合成及其催化性能的评价

由于表面上存在{111}刻面，孪晶边界和应变场，据报道具有二十面体形状的贵金属纳米晶体在一系列催化反应中具有出色的性能。在这里，我们报道了通过用超薄Ru壳形共形涂覆Pd二十面体种子，然后通过化学蚀刻选择性去除Pd核，成功合成了具有面心立方（fcc）结构的Ru二十面体纳米笼。我们发现，溴离子的存在对于Ru原子的逐层沉积至关重要。根据原位XRD，在将Ru纳米笼中的fcc结构转变成常规的六方密堆积（hcp）结构之前，可保留高达300°C的温度。此外，Ru纳米笼的二十面体形状可以在300°C的温度下保存得最多。与表面立方和八面体对应物相比，在表面具有双边界的二十面体Ru二十面体纳米笼显示出对4-硝基苯酚的还原和肼分解的极大增强的活性。当以亲本（受电子邮件保护的）核壳纳米晶体为基准时，所有Ru纳米笼均显示出优异的催化活性。第一性原理密度泛函理论计算还表明，含有残留Pd原子的fcc-Ru二十面体纳米笼比传统的hcp-Ru固体纳米颗粒在催化氮还原以合成氨方面更具前景。借助Pd的表面杂质，二十面体纳米笼的孪生边界区域能够稳定N 与表面立方和八面体对应物相比，在表面具有双边界的二十面体Ru二十面体纳米笼显示出对4-硝基苯酚的还原和肼分解的极大增强的活性。当以亲本（受电子邮件保护的）核壳纳米晶体为基准时，所有Ru纳米笼均显示出优异的催化活性。第一性原理密度泛函理论计算还表明，含有残留Pd原子的fcc-Ru二十面体纳米笼比传统的hcp-Ru固体纳米颗粒在催化氮还原以合成氨方面更具前景。借助Pd的表面杂质，二十面体纳米笼的孪生边界区域能够稳定N 与表面立方和八面体对应物相比，在表面具有双边界的二十面体Ru二十面体纳米笼显示出对4-硝基苯酚的还原和肼分解的极大增强的活性。当以亲本（受电子邮件保护的）核壳纳米晶体为基准时，所有Ru纳米笼均显示出优异的催化活性。第一性原理密度泛函理论计算还表明，含有残留Pd原子的fcc-Ru二十面体纳米笼比传统的hcp-Ru固体纳米颗粒在催化氮还原以合成氨方面更具前景。借助Pd的表面杂质，二十面体纳米笼的孪生边界区域能够稳定N 第一性原理密度泛函理论计算还表明，含有残留Pd原子的fcc-Ru二十面体纳米笼比传统的hcp-Ru固体纳米颗粒在催化氮还原以合成氨方面更具前景。借助Pd的表面杂质，二十面体纳米笼的孪生边界区域能够稳定N 第一性原理密度泛函理论计算还表明，含有残留Pd原子的fcc-Ru二十面体纳米笼比传统的hcp-Ru固体纳米颗粒在催化氮还原以合成氨方面更具前景。借助Pd的表面杂质，二十面体纳米笼的孪生边界区域能够稳定N_2的解离过渡态，减少了整体反应的障碍，并促进了与N ₂脱附过程的竞争。