Abstract:
The presence and nature of surface species formed on a nickel electrode after polarisation in
0.5 mol dm~3 sulphuric acid and 0.5 mol dm-3 sulphuric acid + 0.005 mol dm-3 nickel sulphate has
been investigated by X-ray photoelectron spectroscopy. The film produced in the active, prepassive,
passive and transpassive regions was studied. Nine different species were detected including two
sulphur species. In all cases the electrode was transferred to the spectrometer under nitrogen to
minimise air oxidation of the metal or film.
The binding energies and intensities of the photoelectron peaks were analysed and showed the
presence of NiO and Ni(OH)2. The thickness of the film in the passive and transpassive regions was
calculated, assuming a continuous layer, as 10-20 A.
