O Is spectrum

Figure 5.35. Effect of electrochemical O2- pumping on the O Is spectrum of Pt/YSZ6 (A-C). XPS spectra at 400°C (A) AUWR=0, 1=0 (B) AUWr=1-2 V, 1=40 pA (C) 0 Is difference spectrum.6 Reprinted with permission from the American Chemical Society.

Figure 5.39. Characterization of the spillover species by photoelectron spectra of the Ols region taken from a 0.02 pm2 spot on the Pt surface (a) The residual O Is spectrum after the cleaning cycles (b) The Ols spectrum measured in 02 atmosphere (pO2=lxI0 6 mbar) (c) The Ols spectrum obtained during electrochemical pumping in vacuum with UWr = 1.1 V. R1 and R2 are the components which are formed by adsorption from the gas phase and by electrochemical pumping. The fitting components of the residual oxygen are shown with dashed lines. Photon energy = 643.2 eV, T 350-400°C.67 Reprinted with permission from Elsevier Science.

Figure 5.39a shows the residual O Is spectrum obtained in ultra-high-vacuum after repeated cleaning cycle at 350-400°C. It is clear that there is a significant amount of residual O on the Pt surface which cannot be removed with conventional cleaning procedures. This by itself suffices to prove the presence of the omnipresent backspillover-formed effective double layer on the vacuum exposed Pt surface. 

Fig. 32 a O Is spectrum for oxidized HffSio.sAso.sfAs at a take-off angle of 15°. b Plot of O Is peak intensities vs. take-off angle for different surface components (excluding adsorbed H2O). Reprinted with permission from [113], Copyright Wiley... 

Fig. 5. The O Is spectrum of gaseous Co4(CO)i2- The left-hand peak is due to CO formed in the decomposition of the Co4(CO)i2- The Co4(CO)i2 band has been deconvoluted into two peaks with relative areas of 3 1. Reproduced with permission from Ref.1091...

Fig. 3b XPS spectra of polyimide with sputter-deposited aluminum O Is spectrum.

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. 

For the 1-2-3 materials, the O Is spectrum is narrower than for the 2-1-4 s. It is made up of a dominant component at -529 eV derived from Cu-O planes (accounting for 4 of 7 oxygen atoms in a formula unit) and a shallower component that we attribute to Cu-O chains (accounting for the remainder oxygen atoms). Again, we identify the... 

Fig. 3. ESCA O (Is) spectrum achieved with conventional A1 Ka for AlPO molecular sieve. Note X-ray satellite peaks located at 9.6 and 11.5 eV down field with respect to the principal O (Is) line.

Other oxygen-containing compounds may also be present in the SEI. The O Is spectrum of the anode cycled containing STD with 2 % DMDO electrolyte is slightly different from that of the anode containing STD electrolyte. In addition to the C-O and C=0 peaks observed with the STD electrolyte, a new peak at -534.3 eV is... 

Fig. 3. XPS spectra of sol-gel-derived Z1O2 thin films (a) XPS Zr 3d spectrum and (b) XPS O Is spectrum. Solid lines are the observed XPS spectra and dashed lines are for Zr 3d and O Is sp>ectra, which have two Gaussian peaks fitted by the nonlinear least-squares algorithm (Shimizu et al., 2009).

Figure 12. (a) two peak fit for O Is spectrum for x=0.18 glass, (b) same composition showing all possible contributions to O Is transition... 

Figure 19. Shows the O Is spectrum of the a.) melt-quench glass and b.) solgel glass...

Deconvolution of the O Is spectrum in figure 19b gives a well resolved peak at 532.9 eV associated with Si-O-Si units (BO). The accompanying shoulder at lower binding energy... 

In all three cases, the inclusion of one or two additional components not present in spectra of the reference sample is required to fit the peaks in the corresponding spectra of the modified sample. In the case of the C Is spectrum, components attributable to aliphatic carbon atoms and to carbon atoms in carbonyl groups were added. Additional contributions to the O Is spectrum appear to be associated with an oxide (diseussed below) and an alcohol or ether (C-0) species. The N Is spectrum appears to eomprise contributions from positively charged quaternary amine or ammonium ions, as well as from the imcharged C-N species detected on the control sample. The relative contributions of components in each spectrum are listed in Table 4. 

This sensitivity has inplications for preparation of the surface to be examined. It is very easy for the features of interest to be obscured by deposited impurities or by the consequence of siuface reactions. If the bulk properties of a sample are of interest, then a suitable siuface for examination can be prepared by fracture of a bulk sample under UHV conditions. Some siufaces can be prepared in a controlled environment to avoid contamination and transferred directly to the spectrometer analysis chamber or preparation chamber. Even at the low backgroimd pressures in the analysis chamber, gas molecules wiU adsorb onto and react with surfaces, particularly the often highly reactive surfaces formed by sol-gel. Kim et al. recorded changes to the O Is spectrum from a reduced NiCo204 sanple as a function of time exposed under UHV conditions. The changes to the spectrum (Fig. 6-5) result from reaction with atmospheric H2O and CO. The fit to the O 1 s spectrum shows increased peak intensity at 531.5 and 533.0 eV. Cobalt and nickel hydroxides have... 

FIGURE 3 Deconvolution of the O Is spectrum of original UHMWPE powder recorded at Ub = 0 V. 

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