The paper demonstrates a new technique for preparing nanostructured films of the PdxCe1-xO2-x-δ solid solution. The obtained films are similar to real powder catalysts by their chemical and structural properties and are conductive, which is favorable for the XPS methoda. The effect of the CO+O2 reaction on the oxidized and reduced surfaces is studied using these model objects. The presence of the reversible "PdxCe1-xO2-x-δ 虠 surface palladium forms" transition occurring already at room temperatures in the CO+O2 reaction is shown. Deconvolution of the O1s spectra made it possible for the first time to separate experimentally the contributions from OH- hydroxyl and CO32- carbonate surface groups.