银表面上吸附氧的XPS研究

XPS STUDY OF ADSORPTION OF OXYGEN ON SILVER

本文用XPS研究了银表面上氧的吸附。结果表明,在室温低压下,氧在银表面上存在各种吸附态,它们随氧吸附量增长过程而变化。

The adsorption of oxygen on silver has been studied by XPS. The results indicate that the surface pretreatment method may effect the adsorption ability of oxygen on silver.It is shown that at room temperature and low p(≤10Pa) three adsorption states of oxygen have existed on surface and their Ols binding energies are 528.2, 529.7 and 532.2 eV respectively, corresponding to two different atomic and one molecular adsorption species. We find that one of the atomic oxygen species (ECOls=528.2 eV) may transform to another one (E=529.7 eV) when the exposure of oxygen increases. At larger exposure, some oxygen atoms have entered the bulk of silver and its E(Ols)= 530.2eV.According to the XPS difference spectra of valence band, the resonance of the adsorbate appears at 2.8-3.0 eVand 9.0 eV below E, which are similar to the results of UPS.It is suggested that the atomic and molecular adsorption species of oxygen coexist on silver surface.