我們分別以掃描穿隧電子顯微鏡(STM)研究奈米金粒子以及同步輻射光源的光激發電子能譜儀(PES)研究白金奈米粒子在氧化鋁薄膜上的成長. 我們在超高真空系統中, 利用物理氣象沉積法將奈米粒子成長在300 K, 450 K, 和 570K 的完整有序氧化鋁薄膜Al2O3/NiAl(100)上. 從STM圖形可以觀察到,金奈米粒子在低鍍量時以二維的模式成長.而在較高的樣品準備溫度(450 K和570 K), 則會出現準二維以及較大的三維奈米金粒子共存. 以同步輻射光源的光激發電子能譜儀(PES)研究白金奈米粒子在氧化鋁薄膜上的成長.白金奈米粒子的束縛能隨著升高的樣品溫度往高能量方向偏移.這指出白金奈米粒子可能形成氧化態的粒子.甲醇吸附在白金上當樣品溫度大約120 K時, 然後退火到不同的高溫.我們可以發現到甲醇分解成碳氫化合物在大約380 K時, 而且表面上的汙染物會減少甲醇的分解. We have studied the Au nano-clusters on the well defined support by using scanning tunneling microscopy (STM) and Pt nano-clusters by using synchrotron-based high-resolution photoemission spectroscopy (PES). The nano-clusters were vapor deposited on the well-ordered Al2O3 grown on NiAl (100) in the ultrahigh vacuum environment at 300 K, 450 K, and 570 K (600K for Pt). The STM images show that the Au nano-clusters form two-dimensional (2D) clusters at small coverage. At the elevated sample prepare temperature, the quasi-2D (height of 1 – 2 atomic layers) and greater three–dimensional clusters coexist. We studied Pt nano-clusters on the well-ordered Al2O3 by using PES. The Pt 4f binding energy (BE) shifts to higher values with the sample temperature. This implies that the Pt clusters are oxidized at the higher sample temperature. The methanol was adsorbed on Pt clusters at 120 K and subsequently annealed to different temperatures. The methanol decomposes to hydrocarbon at sample temperature of annealing to 380 K. The amount of adsorption methanol was decreased with the increasing contamination.
