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Abstract

X-ray diffraction (XRD) studies on metal clusters are reported and results for several systems are presented. Special emphasis is devoted to the use of the so called Debye Function Analysis (DFA technique) as a tool for numerical simulation of the diffracted intensity of polydispersed nanocrystalline systems. This method is most commonly applied in the field of highly dispersed supported catalysts. For small particles, XRD become increasingly surface sensitive. By analysing in situ one can then observe structure-related reactions taking place at the surface. This is exemplified by proof of the Sales-Turner-Maple mechanism for CO oxidation over supported platinum. Refined experimental and numerical methods are described which give reliable data despite a high background from the support. Of further interest is the observation of clusters in the sub-nanometer size range, that are difficult to analyse by HRTEM, and the characterisation of bimetallic colloids.