In Situ Atomic-Scale Studies of the Formation of Epitaxial Pt Nanocrystals on Monolayer Molybdenum Disulfide.
In Situ Atomic-Scale Studies of the Formation of Epitaxial Pt Nanocrystals on Monolayer Molybdenum Disulfide.
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DOI：
10.1021/acsnano.7b03648
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发表时间：
2017-08
期刊：
影响因子：
17.1
通讯作者：
Shanshan Wang;H. Sawada;Qu Chen;Grace G. D. Han;C. Allen;A. Kirkland;J. Warner
中科院分区：
文献类型：
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作者：
Shanshan Wang;H. Sawada;Qu Chen;Grace G. D. Han;C. Allen;A. Kirkland;J. Warner
Pt-Pt：MoS 2杂化材料具有很好的析氢催化性能，在原子尺度上了解它们的详细结构对进一步开发至关重要。在这里，我们使用像差校正透射电子显微镜中的原位加热保持器来研究在加热到800 °C时从前体直接在单层MoS 2表面上形成Pt纳米晶体。孤立的单个Pt原子和小的纳米团簇在原位加热后观察到，Pt纳米晶体和下面的单层MoS 2之间有两种类型的优先排列。应变效应和厚度的变化的超小Pt的负载在MoS 2的研究，揭示了单原子平面形成的非层状面心立方体Pt配置与7-10%的晶格膨胀相比，体Pt。Pt纳米晶体被无定形碳层包围，并且在某些情况下在加热后蚀刻了局部周围的MoS 2材料。电子束照射也启动Pt的局部MoS 2的蚀刻，我们在原子分辨率的真实的时间研究这个过程。这些结果表明，Pt纳米晶体周围碳的存在不影响它们与MoS 2晶格的外延关系。碳层内的单个Pt原子也在高温下被固定。这些结果为Pt：MoS 2杂化材料的形成提供了重要的见解。
Pt-nanocrystal:MoS2 hybrid materials have promising catalytic properties for hydrogen evolution, and understanding their detailed structures at the atomic scale is crucial to further development. Here, we use an in situ heating holder in an aberration-corrected transmission electron microscope to study the formation of Pt nanocrystals directly on the surface of monolayer MoS2 from a precursor on heating to 800 °C. Isolated single Pt atoms and small nanoclusters are observed after in situ heating, with two types of preferential alignment between the Pt nanocrystals and the underlying monolayer MoS2. Strain effects and thickness variations of the ultrasmall Pt nanocrystal supported on MoS2 are studied, revealing that single atomic planes are formed from a nonlayered face-centered cubic bulk Pt configuration with a lattice expansion of 7-10% compared to that of bulk Pt. The Pt nanocrystals are surrounded by an amorphous carbon layer and in some cases have etched the local surrounding MoS2 material after heating. Electron beam irradiation also initiates Pt nanocrystal etching of the local MoS2, and we study this process in real time at atomic resolution. These results show that the presence of carbon around the Pt nanocrystals does not affect their epitaxial relationship with the MoS2 lattice. Single Pt atoms within the carbon layer are also immobilized at high temperature. These results provide important insights into the formation of Pt:MoS2 hybrid materials.