Molybdenum XPS analysis is typically performed on the 3d region (Figure 1). This region commonly overlaps with the S 2s region, which may complicate the deconvolution of molybdenum sulfates. Additional regions which may overlap with the Mo 3d region include Ta 4d, Cs 4s, Se 3s and Ce 4p (only slightly, but record an extended region to the low binding energy side to aid deconvolution). The peaks have a reasonable doublet separation of 3.15 eV.

Figure 1: Mo metal XPS spectra(1)

As can be seen in figure 1, the peaks of Mo metal are asymmetric in shape, however the oxides will possess a symmetric shape.

Typical binding energies for common Mo species may be found in table 1.

Species Binding energy / eV Charge Ref Ref
Mo 227.8 Au 4f / 84 eV 2
MoO2 228.7 Au 4f / 84 eV 2
MoO3 232.8 Au 4f / 84 eV 2
Table 1: Common binding energies of Mo species


  1. Spectra recorded by HarwellXPS
  2. Werfel, F. and E. Minni (1983). “Photoemission study of the electronic structure of Mo and Mo oxides.” Journal of Physics C: Solid State Physics 16(31): 6091. Read it online here.

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