The electrochemical behaviours of the Magneli phase titanium oxides with the general formula TixO2x-1 have been investigated. Surface analysis of these ceramic materials was performed using X-ray photoelectron spectroscopy in order to determine the surface composition. It was shown that the surface layers contain mainly Ti-IV. When these materials are used as an anode for oxygen evolution, in sulfuric acid, the XPS spectrum shows considerable modification in the O1s region, due to an important contribution of hydroxyl groups and the adsorption of sulfate anions.