Lee Sungsik, Fan Chaoyang, Wu Tianpin, Anderson Scott L
Department of Chemistry, University of Utah, 315 South 1400 East Room 2020, Salt Lake City, Utah 84112-0850, USA.
J Phys Chem B. 2005 Jun 9;109(22):11340-7. doi: 10.1021/jp0502407.
Size-selected gold clusters, Au(n)(+) (n = 1, 3, 4), were deposited on an ordered Al(2)O(3) film grown on NiAl(110), and changes in morphology and electronic properties with deposition/annealing temperature and cluster size were investigated by X-ray photoelectron spectroscopy (XPS) and ion-scattering spectroscopy (ISS). Extensive agglomeration was observed by ISS for annealing temperatures above 300 K, accompanied by large shifts in the Au XPS binding energy. Agglomeration is more extensive in room-temperature deposition, compared to samples prepared by low-temperature deposition, then annealed to room temperature. Agglomeration is also observed to be dependent on deposited cluster size. CO adsorption was studied by ISS and temperature-programmed desorption, and we looked for CO oxidation under conditions where substantial activity is seen for Au(n)/TiO(2). No activity was observed for Au(n)/Al(2)O(3). The differences between the two systems are interpreted in terms of the nature of the metal-support interactions.
尺寸选择的金簇，Au(n)(+)（n = 1, 3, 4），沉积在生长于NiAl(110)上的有序Al₂O₃薄膜上，通过X射线光电子能谱（XPS）和离子散射谱（ISS）研究了其形貌和电子性质随沉积/退火温度以及簇尺寸的变化。通过ISS观察到，退火温度高于300 K时会发生广泛的团聚，同时Au XPS结合能有较大位移。与通过低温沉积然后退火至室温制备的样品相比，室温沉积时团聚更为广泛。还观察到团聚取决于沉积的簇尺寸。通过ISS和程序升温脱附研究了CO吸附，并且我们在对Au(n)/TiO₂观察到大量活性的条件下寻找CO氧化。未观察到Au(n)/Al₂O₃有活性。根据金属-载体相互作用的性质解释了这两个体系之间的差异。
