Analysis of the oxidation state of platinum particles in supported catalysts by double differentiation of XPS lines

Resumo

In the work the double differentiation of functions describing the Pt4f_7/2 band in the XPS spectra of model supported Pt/SiO₂ catalysts is performed in order to determine the number of different chemical states of platinum particles. The functions for the differentiation are obtained by the deconvolution of the experimental spectral contour into two spin-orbit components. As a result of the performed analysis of the number and position of the minima of the second derivative of the function of Pt43_7/2 the conditions of the oxidation of platinum particles in the Pt/SiO₂ sample on treating in a NO + O₂ mixture and the reduction of platinum oxide particles on interacting of the PtO_x/SiO₂ sample with hydrogen are determined.