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).
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|
TiO2 is readily reduced by Ar+ sputtering, forming suboxides.
- 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.
- 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.
- 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.
- Diebold, U. and T. Madey (1996). “TiO2 by XPS.” Surface Science Spectra 4(3): 227-231. Read it online here.
- Gonbeau, D., et al. (1991). “XPS study of thin films of titanium oxysulfides.” Surface science 254(1-3): 81-89. Read it online here.