XP Spectroscopy is used to compare the states of the supported platinum particles in the samples of the Pt/Sibunit catalyst and the Pt/HOPG model system after treating in NO2 at room temperature and pressure of 3 x 10(-6) mbar. It is shown that in both cases the platinum particles are not oxidized completely. The comparison of the spectra obtained for the Pt/Sibunit sample in the Pt 4f and Pt 3d(5/2) regions with the use of Al K-alpha and Ag L-alpha radiations serves as a basis for an assumption that the particles of platinum after being treated in NO2 have the core (metallic Pt) shell (platinum oxides) structure. (C) 2017 Elsevier B.V. All rights reserved.