Toward Phase and Catalysis Control: Tracking the Formation of Intermetallic Nanoparticles at Atomic Scale
Toward Phase and Catalysis Control: Tracking the Formation of Intermetallic Nanoparticles at Atomic Scale
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DOI：
10.1016/j.chempr.2019.02.026
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发表时间：
2019-05
期刊：
影响因子：
23.5
通讯作者：
T. Ma;Shuai Wang;Minda Chen;Raghu V. Maligal-Ganesh;Lin‐Lin Wang;Duane D. Johnson;M. Kramer
中科院分区：
文献类型：
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作者：
T. Ma;Shuai Wang;Minda Chen;Raghu V. Maligal-Ganesh;Lin‐Lin Wang;Duane D. Johnson;M. Kramer
金属间化合物纳米颗粒（iNP）通过形成有序相在催化应用中取得了巨大的成功。然而，在控制金属间相和定制其催化性能方面起着关键作用的合金化机制的原子级理解仍然是难以捉摸的。在这项研究中，我们发现了一个连续的形成有序的Pt 3Sn和PtSn相的Pt-Sn iNP在一个明确的纳米反应器内，在高温下通过使用原位扫描透射电子显微镜生长。我们发现，Sn的表面介导的扩散控制的反应的整体动力学，而独特的连贯的界面结构是决定性的PtSn转换。然后，我们进一步控制Pt-Sn iNP的相选择，并展示了它们可区分的催化行为。我们的研究结果不仅提供了详细的实验证据，在金属间纳米系统的合金化机制，但也铺平了道路，机械控制的合成和催化性能的iNPs。
Intermetallic nanoparticles (iNPs) have yielded enormous successes in catalytic applications by the formation of ordered phases. However, atomic-level understanding of the alloying mechanism, which plays a pivotal role in controlling intermetallic phases and tailoring their catalytic properties, is still elusive. In this study, we discovered a consecutive formation of ordered Pt3Sn and PtSn phases during the growth of Pt-Sn iNP inside a well-defined nano-reactor at elevated temperature by usingin situscanning transmission electron microscopy. We found that the surface-mediated diffusion of Sn controls overall dynamics of the reaction, while the unique coherent interfacial structure is determinative for the PtSn transformation. We then further controlled the phase selection of Pt-Sn iNPs and demonstrated their distinguishable catalytic behaviors. Our findings not only provide detailed experimental evidence on the alloying mechanism in intermetallic nanoscale systems but also pave the way for mechanistic control of synthesis and catalytic properties of iNPs.