Dearg Malcolm, Lethbridge Sean, McCormack James, Palmer Richard E, Slater Thomas J A
Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Cardiff, CF24 4HQ, UK.
School of Physics, Engineering and Technology, University of York, York, YO10 5DD, UK.
Nanoscale. 2024 Jun 6;16(22):10827-10832. doi: 10.1039/d4nr00978a.
In this study, aberration-corrected scanning transmission electron microscopy is employed to investigate the morphology of Au clusters formed from the aggregation of single atoms sputtered onto an amorphous carbon surface. The morphologies of surface-assembled clusters of > 100 atoms are referenced against the morphologies of size-selected clusters determined from previously published results. We observe that surface-assembled clusters (at the conditions employed here) are approximately spherical in shape. The structural isomers of the imaged clusters have also been identified, and the distribution of structural types is broadly in agreement with those from size-selected cluster deposition sources. For clusters of approximately 147 atoms, we find a preference for icosahedra over decahedra and truncated octahedra, but at this size there is a high proportion of unidentified/amorphous structures. At around 309 atoms, we find a preference for decahedra over icosahedra and truncated octahedra, but over half the structures remain unidentifiable/amorphous. For sizes above approximately 561 atoms we are able to identify most of the structures, and find decahedra are still the most favoured, although in competition with single-crystal fcc morphologies. The similarity in structure between surface-assembled and size-selected clusters from a cluster source provides evidence of the relevance of size-selected cluster studies to clusters synthesised by other, industrially relevant, methodologies.
在本研究中，采用像差校正扫描透射电子显微镜来研究溅射在非晶碳表面的单原子聚集形成的金团簇的形态。将超过100个原子的表面组装团簇的形态与根据先前发表的结果确定的尺寸选择团簇的形态进行对比。我们观察到（在本文所采用的条件下）表面组装团簇的形状近似为球形。还识别了成像团簇的结构异构体，并且结构类型的分布与来自尺寸选择团簇沉积源的分布大致一致。对于大约147个原子的团簇，我们发现二十面体比十面体和截角八面体更受青睐，但在这个尺寸下，有很大比例的结构无法识别/呈非晶态。在大约309个原子时，我们发现十面体比二十面体和截角八面体更受青睐，但超过一半的结构仍然无法识别/呈非晶态。对于大约561个原子以上的尺寸，我们能够识别大多数结构，并且发现十面体仍然是最受青睐的，尽管它与单晶面心立方形态存在竞争。来自团簇源的表面组装团簇和尺寸选择团簇之间的结构相似性为尺寸选择团簇研究与通过其他与工业相关的方法合成的团簇的相关性提供了证据。
