Crystalline and electronic structure of Ni nanoclusters supported on Al2O3 and Cr2O3 investigated by XRD, XAS and XPS methods

In this paper, we investigate the crystalline and electronic structure of Ni nanoclusters supported on Al2O3 and Cr2O3 obtained at different reduction temperatures. Their physical properties were characterized by powder X-ray diffraction, X-ray absorption spectroscopy and X-ray photoelectron spectroscopy techniques. The global parameters of the active metal nanostructure such as average crystallite size and the microstrain are obtained by the generalized Fermi function for fitting the experimental X-ray line profiles. By X-ray absorption spectroscopy we evidenced a diminution of the coordination number in the first shell of the nickel atoms. In order to characterize the electronic structure of the active metal, X-ray photoelectron spectroscopy measurements were performed. Our results give additional information about the strong interaction between the metal clusters and oxide supports.