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一、引言在多相催化的研究中,对载体表面结构和吸附行为的了解十分重要。在过去的几十年中,许多用于表面结构分析的技术先后问世,如透射电子显微镜(TEM)、扫描电子显微镜(SEM)、场发射显微镜(FEM)、场离子显微镜(FIM)、低能电子衍射(LEED)俄歇谱仪(AES)、电子探针等。这些技术的发展和应用,在表面科学和多相催化领域的研究中起着重要的作用。但任何一种技术在应用中都存在这样或那样的局限,例如LEED要求样品具备周期性结构,光学显微镜和SEM的分辨率不足以分辨出表面原子。高分辨TEM主要用于薄层样品的体相和界面研究。FEM和FIM只能探测半径小于1000A的针尖上的原子结构和二维几何性质,且制样技术复杂,可用来作为样品的研究对象十分有限。还有一些表面分析技术,实际上观察到的是对较大区域(如大于10nm)和一定深度
I. INTRODUCTION In the study of heterogeneous catalysis, understanding of the surface structure and adsorption behavior of the support is very important. In the past few decades, many techniques for the analysis of surface structures have come into being, such as Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Field Emission Microscopy (FEM), Field Ion Microscopy (FIM), Low Energy Electron Diffraction (LEED) Auger spectrometer (AES), electron probe and so on. The development and application of these technologies play an important role in the research of surface science and heterogeneous catalysis. However, any one of these technologies has some limitations in its application. For example, LEED requires that samples have periodic structures and the resolution of optical microscopes and SEMs is insufficient to distinguish surface atoms. High-resolution TEM is mainly used for bulk phase and interfacial studies of thin-layer samples. FEM and FIM can only detect the atomic structure and the two-dimensional geometry on the tip of a radius less than 1000A, and the sample preparation technique is complex, and the objects that can be used as a sample are very limited. There are some surface analysis techniques, in fact, observed for large areas (such as more than 10nm) and a certain depth