Use of oxygen/nickel ratios in the XPS characterisation of oxide phases on nickel metal and nickel alloy surfaces

• Published in: Journal of electron spectroscopy and related phenomena Vol. 185; no. 5-7; pp. 159 - 166
• Main Authors: Payne, B.P., Biesinger, M.C., McIntyre, N.S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2012
• Subjects: Alloying additive; Atomic ratios; Mathematical analysis; Mixed phase oxides; Ni oxides; Nickel; Nickel base alloys; Oxides; Phases; Spectra; X-ray photoelectron spectroscopy; XPS; Atomic ratios; XPS; Mixed phase oxides; Ni oxides
• ISSN: 0368-2048; 1873-2526
• DOI: 10.1016/j.elspec.2012.06.008

► The O/Ni atomic ratios for a number of Ni oxides were calculated. ► The O/Ni ratios found to correspond well with the expected stoichiometry. ► Metal 2p peak shapes and O/Ni ratios used to estimate proportions of mixed oxides on metal surfaces. The O/Ni ratios derived from the X-ray photoelectron (XP) spectra of a number of well-characterised Ni oxides were calculated and found to correspond well to the expected O/Ni ratios for these oxides. The measured ratios, combined with the characteristic XP spectra, provide a higher level of confidence to the assignment of O 1s chemical species, particularly for surfaces with multiple phases present. As examples of this, we discuss the additional information imparted by O/Ni ratios measured for oxides that were electrochemically grown on Ni and NiCr-20% alloy surfaces.