Binding energy, in XPS

Auger energies are as element specific as binding energies in XPS. However, chemical information such as oxidation states is much more difficult to abstract. Three effects can occur ... 

The local environments of T-atoms in SAPO materials were examined using solid-state NMR, a bulk probe, and XPS, a surface sensitive probe. T-a-tom 2 p binding energies in XPS were found to vary in a predictable fashion with changes in NMR chemical shifts. The comparison demonstrates that XPS is sensitive to variations in the second coordination sphere for T-atoms in SAPO molecular sieves. XPS was also found to give a reasonable, quantitative measure of superficial (surface) T-atom fractions thus providing information about elemental homogeneity by comparison to bulk chemical analysis. 

XP survey spectra are not particularly useful for identifying a surface-deposited material, as they are purely qualitative. High-resolution spectra are more informative and can be used semiquantitatively. As in the survey spectra, the x-axis corresponds to the binding energy in eV, and the y-axis is counts. Carbon is found in different oxidation states in the coating, as can be seen in Figure 4. 

Table HI. XPS of AuSn Particles Prepared in Acetone Binding Energies in eV...

Leary and Campbell (18) have reported that both carboxylic acid and amide of PMDA-ODA polyamic acid, which is baked at 120 °C to remove the NMP solvent, react with KOH. They have observed changes of carbonyl binding energies in the XPS spectra. On the other hand, in the... 

X-ray photoelectron spectroscopy (XPS) has been used to determine phosphorus (and oxygen) core binding energies in P406 (144) and P4O10 (145-147). The energy values obtained are listed in Table XX. As in... 

For the purpose of the present chapter, a comment on the interpretation of oxygen Is binding energies in oxides seems appropriate. The contribution of the surface terminating layer and of a possible adsorbate to the total O Is spectrum of an oxide catalyst is low (an estimated 15% for laboratory XPS) as in oxides the depth of information [33] is commonly larger than estimated from the universal relation between kinetic energy and escape depth, which is vahd for metals only. 

X-ray photoelectron spectra of catalysts were measured using a Shimadzu ESCA-850 after pretreatment at 623 K for 0.5 h in an H2 flow of 200 cm /min within the prechamber of the apparatus. The binding energies of XPS were referred to the evaporated Au on the surface as the internal standard with the Au 4f /2 level at 83.8 eV. 

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