Local, global and electronic structure of supported gold nanoclusters determined by EXAFS, XRD and XPS methods

We analyze gold nanoclusters as supported catalysts by extended X-ray absorption fine structure, X-ray diffraction and X-ray photoelectron spectroscopy in order to determine their local, global and electronic structure. The present study points out a strong deformation of the local structure of the metal due to its interaction with oxide supports. We determine the particle size distribution and microstrain functions of the Au nanoclusters by X-ray diffraction method. Based on X-ray absorption fine structure spectroscopy analysis we show that the entire local structure of the investigated systems is strongly distorted regarding the average Au–Au coordination number. The distances between atoms are practically the same as standard Au foil. The strong metal–support interaction is confirmed by the change in shape of the electron transition probability densities that appear in the Au L III-edge. From XPS investigations we find electronic states corresponding to gold as well as to the oxide supports.