Electrochemically Grown Silver Oxide (Ag2O) by XPS

XPS data have been obtained from silver oxide (Ag2O) thin films which were prepared by the anodic oxidation of sputter cleaned silver metal in alkaline solution (1M NaOH). The electrochemical oxidation was performed under a protecting noble gas atmosphere in a separate chamber flanged to the UHV spectrometer, so that any contact with laboratory air was avoided. Ex-situ x-ray diffraction revealed the polycrystalline structure of the oxides without any preferred orientation. The following spectra will be presented in the present contribution, revealing the high phase purity and quality of the electrochemically grown oxide layers: survey spectrum, spectra of major elements silver and oxygen (Ag 3d and O 1s), and spectrum of minor element carbon (C 1s). In contrast to previously published data of ex-situ prepared powder samples which revealed a huge amount of contaminations by e.g. carbonates, hydroxides, etc., the detailed XPS data evaluation shows that only minor contaminations are present on the electrochemically grown oxides. Therefore, these spectra are extremely useful in XPS-studies of Ag/O-systems such as silver epoxidation catalysts. (C) 2011 American Vacuum Society.