论文标题
氧化铝上的普通PT簇的常规阵列：Al $ _2 $ o $ _3 $/ni $ _3 $ al（111）上的新上层结构（111）
Regular Arrays of Pt Clusters on Alumina: A New Superstructure on Al$_2$O$_3$/Ni$_3$Al (111)
论文作者
论文摘要
通过高温氧化Ni $ _3 $ al（111）表面获得的氧化铝超薄膜是生长常规金属簇阵列的好模板。直到现在，已经观察到两个六角形组织，分别在4.1和2.4 nm之间观察到了距离。在本文中，我们报告了原位放牧发病率小角度X射线散射（GISAXS）的研究，表明PT在室温（RT）下沉积（RT），而对于低覆盖率，则形成了一个新的六边形结构，在1.38 nm的簇之间距离。首次获得了一个非常高的密度（5.85x10 13 cm $ $^{ - 2} $）的微小PT簇（1-6个原子）的组装，并在氧化铝表面上呈现一个好的组织。该系统可用于通过表面科学技术研究单原子催化（SAC）的新新兴领域。通过在573 K处的沉积，小pt簇在网络结构上组织。通过在预先形成的PD种子上在573 K处沉积PT，在DOT结构上组织了包含一百个原子的大PT（PD）簇，并且它们保持高达733K。我们显示了三个结构相互关联。氧化铝表面上的PT簇的不同组织通过与PT原子的不同吸附能相对应的3种类型的位点来解释。
Alumina ultrathin films obtained by high temperature oxidation of a Ni$_3$Al (111) surface are a good template to grow regular arrays of metal clusters. Up to now two hexagonal organizations called 'dot' and 'network' structures have been observed with distances between clusters of 4.1 and 2.4 nm, respectively. In the present article we report on an investigation by in situ Grazing Incidence Small Angle X-ray Scattering (GISAXS), showing that Pt deposited at room temperature (RT) and for a low coverage forms a new hexagonal structure with a distance between clusters of 1.38 nm. For the first time, an assembly of tiny Pt clusters (1-6 atoms) with a very high density (5.85x10 13 cm$^{-2}$) and presenting a good organization on an alumina surface, is obtained. This system could be used to investigate by surface science techniques the new emerging field of Single Atom Catalysis (SAC). By deposition at 573 K small Pt clusters are organized on the network structure. By deposition of Pt at 573 K on pre-formed Pd seeds, large Pt (Pd) clusters containing a hundred of atoms are organized on the dot structure and they remain organized up to 733 K. We show that the three structures are interrelated. The different organizations of the Pt clusters on the alumina surface are explained by the presence of 3 types of sites corresponding to different adsorption energy for Pt atoms.
