Department of Chemical Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany.
J Am Chem Soc. 2011 Jul 13;133(27):10668-76. doi: 10.1021/ja204798z. Epub 2011 Jun 20.
The nucleation and electronic structure of vapor-deposited Au on hydroxylated MgO(001) surfaces has been investigated under ultrahigh vacuum conditions. Hydroxylated MgO(001) surfaces with two different hydroxyl coverages, 0.4 and 1 monolayer, respectively, were prepared by exposure to water (D(2)O) at room temperature. Scanning tunneling microscopy experiments show significantly higher gold particle densities and smaller particle sizes on the hydroxylated MgO surface as compared to gold deposited on clean MgO(001). Infrared spectroscopy and X-ray photoelectron spectroscopy experiments were performed to reveal details about the initial nucleation of gold. Gold atoms are found to chemically interact with a specific type of hydroxyl groups on the MgO surface, leading to the formation of oxidized gold particles. The enhanced adhesion of Au particles, which is due to the formation of strong Au-O interfacial bonds, is responsible for the observed higher stability of small Au clusters toward thermal sintering on hydroxylated MgO surfaces. The results are compared to similar studies on Au/TiO(2)(110) model systems and powder samples prepared by the deposition-precipitation route.
在超高真空条件下，研究了蒸气沉积在羟基化 MgO(001)表面上的 Au 的成核和电子结构。通过在室温下暴露于水（D(2)O），分别制备了具有两种不同羟基覆盖率，分别为 0.4 和 1 单层的羟基化 MgO(001)表面。扫描隧道显微镜实验表明，与沉积在清洁 MgO(001)上的金相比，金在羟基化 MgO 表面上的金颗粒密度更高，颗粒尺寸更小。进行了红外光谱和 X 射线光电子能谱实验以揭示金初始成核的细节。发现金原子与 MgO 表面上特定类型的羟基发生化学相互作用，导致氧化金颗粒的形成。由于形成了强的 Au-O 界面键，Au 颗粒的附着力增强，这是观察到在羟基化 MgO 表面上小的 Au 团簇对热烧结的稳定性更高的原因。将结果与类似的 Au/TiO(2)(110)模型体系和通过沉积-沉淀法制备的粉末样品的研究进行了比较。
