Curve fitting analysis of ESCA Ni 2p spectra of nickel-oxygen compounds and Ni/Al2O3 catalysts

Nonlinear least-squares curve fitting is used to analyze Ni 2p spectrra obtained from various nickel-oxygen compounds and Ni/Al2O catalysts. Apart from NiO, which shows a characteristic discrete satellite peak 2 eV from the main 2p/sub 3/2/ peak, all other spectra exhibit variable peak asymmetry assigned to multiplet splitting effects. By the use of a single extra peak to describe this asymmetry, the relative satellite/main peak intensity ratio can be used as an indication of the chemical state of nickel. Results for Ni/Al3O3 catalysts agree with reduction studies from previous work about the nature of nickel species on the surfaces of these catalysts at various nickel loadings