Information about structure and chemical composition of irreversibly deposited tellurium on Pt(111) in sulphuric acid solution has been gathered ex-situ by LEED and XPS as a function of emersion potential. From the chemical shift of the Te 3d(5/2) level, a change in the valence state from Te(0) to Te(IV) with positive-going electrode potential is deduced, the total amount of Te on the surface remaining constant. XP spectra also reveal the presence of Te(II) on the surface, which may be a consequence of partial double layer collapse in the emersed state. The maximum coverage of Te(0) is around 0.4 ML, as derived by XPS and LEED. The coadsorption of anions accompanying the valence transition from Te(0) to Te(IV) has also been studied. It is demonstrated that the very first potential cycle in the region of the surface redox peak, i.e. between +0.65 and +0.45 V versus Ag/AgCl, brings about drastic changes in the adlayer properties. Although XPS has provided strong evidence for a change in the valence state of adsorbed Te on Pt(111), this system has demonstrated the limitations of the ex-situ approach to obtain electrochemical information.