X-ray photoelectron spectroscopy (XPS) has been used to study the redox state of transition metal oxides in sodium silicate glasses with compositions 0.30Na2O-0.70SiO2 and 0.3Na2O-0.6SiO2-0.1TMO, where TMO = Fe2O3, CuO and CoO. From the analysis of the core level spectra of the transition metals, it was found that both Fe2+ and Fe3+ exist simultaneously in the iron doped glass, while Cu+ was the only species present in the copper doped glass. In the cobalt doped glass, Co2+ was found to exist in both tetrahedral (tet) and octahedral (oct) co-ordinations. From the analysis of the O 1s spectra, it was possible to discriminate between bridging and non-bridging oxygen atoms in each glass sample. It was also shown that the non-bridging oxygen contribution to the O 1s spectra can be simulated by summing the contributions from SiONa, SiOFe2+ and SiOFe3+ for the iron doped glass, SiONa and SiOCu+ for the copper doped glass and SiONa, SiOCo2-(tet) and SiOCo2+(oct) for the cobalt doped glass. The quantitative values for the [Fe2+]/[Fe] and [Co2+(tet)]/[Co] concentrations ratios were found from the analysis of the Fe 3p and Co 3p core level spectra, respectively.
|Number of pages
|Journal of Electron Spectroscopy and Related Phenomena
|Published - Jun 1999
Bibliographical noteFunding Information:
The authors would like to acknowledge the support of King Fahd University of Petroleum & Minerals.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Physical and Theoretical Chemistry