二氧化钛纤维表面担载Pt纳米结构的原子力显微镜研究

Atomic Force Microscopy Study of Nanostructure of Pt Loaded on TiO_2 Fiber

通过原子力显微镜研究了二氧化钛纤维表面担载Pt的表面形貌及其结构．结果表明，TiO2纤维表面担载的Pt具有微米尺度的近似六边形或者近似长方形的结构，与在单晶TiO2（110）表面的Pt纳米簇形貌相似，但尺度较大．TiO2纤维担载的Pt表面明显存在不同高度的台阶结构，台阶高度以2～4倍Pt（111）晶面面间距的高度为主．由Pt在TiO2纤维表面的形貌与纤维的纳米晶粒排布有序性推测可知，Pt与TiO2纤维存在强的相互作用，可能正是这种强相互作用和表面台阶结构才使TiO2表面担载的Pt虽是微米尺寸但仍具有高光催化活性．

The surface topography and structure of platinum loaded on TiO2 fiber were investigated by atomic force microscopy. The micron-sized platinum domains were rectangle-like on the TiO2 fiber with low content of Pt but were hexagon-like on the TiO2 fiber with high content of Pt. The topography of Pt domains on TiO2 fiber was similar to Pt nanocluster on TiO2 （110）, but the size of Pt domains was obviously larger. The specific topography of Pt domains and the ordered distribution of nano-crystals of TiO2 fiber implied that there was a strong metal-support interaction between Pt and TiO2 fiber. There were many terraces on the Pt domains, and the height of terraces mainly ranged from two to four times the interplanar distance of Pt （111）. Moreover, the specific surface area of Pt/TiO2 fiber was almost unchanged before and after the loading of Pt. The strong metal-support interaction and the terrace structure of Pt might be the reasons that the photocatalytic activity of Pt/ TiO2 fiber was high although the Pt was micron-sized domains.