XPS of titanium is typically performed on the 2p region. Unlike later first row TMs Ti 2p does not undergo multiplet splittings in it’s compounds, due to a lack of unpaired d-electrons. Ti 2p does, however, feature asymmetric peak broadening due to a Coster-Kronig transition and so care should be taken when peak fitting. The Ti 2p1/2 may be fit with a FWHM wider than that of the Ti 2p3/2.

Ti 2p peaks are mostly uncomplicated doublets (Figure 1) with a separation of around 6 eV (see table 1).

Figure 1: TiO2 Ti 2p XPS(1)

The exception to this is titanium nitride (TiN) which exhibits a complex structure including shake-up peaks, bulk and surface plasmons.(2)

Species EB / eV Doublet Separation / eV Charge Ref Ref
Ti metal 454 6.1 Au 4f (84 eV) 3
TiN 455.3 6 Au 4f (84 eV) 3
TiO2 459.3 5.7 Au 4f (84 eV) 4
Ti2O3 (Ti3+) 456.6 C 1s (284.6 eV) 5
TiO (Ti2+) 454.4 C 1s (284.6 eV) 5
TiS2 456 C 1s (284.6 eV) 5
TiS3 455.9 C 1s (284.6 eV) 5
Table 1: Typical binding energies for various common Ti species

TiO2 is readily reduced by Ar+ sputtering, forming suboxides.


  1. Kumar, S., et al. (2017). “P25@ CoAl layered double hydroxide heterojunction nanocomposites for CO2 photocatalytic reduction.” Applied Catalysis B: Environmental 209: 394-404. Read it online here.
  2. Jaeger, D. and J. Patscheider (2013). “Single crystalline oxygen-free titanium nitride by XPS.” Surface Science Spectra 20(1): 1-8. Read it online here.
  3. Badrinarayanan, S., et al. (1989). “XPS studies of nitrogen ion implanted zirconium and titanium.” Journal of Electron Spectroscopy and Related Phenomena 49(3): 303-309. Read it online here.
  4. Diebold, U. and T. Madey (1996). “TiO2 by XPS.” Surface Science Spectra 4(3): 227-231. Read it online here.
  5. Gonbeau, D., et al. (1991). “XPS study of thin films of titanium oxysulfides.” Surface science 254(1-3): 81-89. Read it online here.

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