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A kinetic Monte Carlo-blueprint for oxygen reduction on oxide-supported PtNi nanoalloys.
The Journal of Chemical Physics ( IF 4.4 ) Pub Date : 2020-01-21 , DOI: 10.1063/1.5129670
D Schmidt 1 , G G Asara 2 , F Baletto 2
Affiliation  

To elucidate the effect of the architecture of supported bimetallic nanocatalysts, we developed a new lattice kinetic Monte Carlo based on the classifying and counting adsorption sites with respect to their generalized coordination number. We employed this tool to estimate the activity of MgO-supported PtNi nanoalloys for oxygen reduction. We demonstrated that the presence of Ni atoms in contact with the substrate massively enhances their activity with at least a 7-order of magnitude increase in the turnover of water production with respect to the case where only Pt lay at the interface. We further discussed how the nanoalloy shape affects the activity showing that truncated octahedra are 102 more active than cuboctahedra of similar size. We explained our results in terms of their distinct distribution and occurrence of the most active sites for oxygen reduction leading to the stabilization of different chemical species during the reaction dynamics. Our results suggest that engineering multifaceted and long edge PtNi-nanoalloys with a certain chemical ordering at the support interface would improve their catalytic performance for the oxygen reduction reaction.

中文翻译:

动力学蒙特卡罗蓝图,用于在氧化物负载的PtNi纳米合金上进行氧还原。

为了阐明负载型双金属纳米催化剂的结构效果,我们基于对吸附位点的广义配位数进行分类和计数,开发了一种新的晶格动力学蒙特卡罗方法。我们使用该工具估算了MgO负载的PtNi纳米合金的减氧活性。我们证明了与基体接触的镍原子的存在大大提高了其活性,相对于只有Pt置于界面的情况,水的生产周转率至少提高了7个数量级。我们进一步讨论了纳米合金形状如何影响活性,表明截短的八面体比类似尺寸的立方八面体的活性高102。我们根据其独特的分布和最活跃的氧还原位点的出现来解释我们的结果,从而导致反应动力学过程中不同化学物种的稳定化。我们的结果表明,在载体界面上以一定的化学顺序对多面和长边的PtNi-纳米合金进行工程改造将改善其对氧还原反应的催化性能。
更新日期:2020-01-22
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