X-ray photoelectron spectroscopy study of copper sodium silicate glass surfaces

Copper oxide-containing, sodium silicate glasses with composition (0.70 - x)SiO2-0.30Na2O-xCuO (x in the range 0–0.2), were prepared by conventional melting and casting. The surface structure has been investigated by X-ray photoelectron spectroscopy. Evidence for the presence of copper in the Cu+ state for glasses with x ≤ 0.14, and for both oxidation states (Cu+ and Cu2+) in the glass where x = 0.18, has been obtained from the “shake up” satellite structure of the Cu 2p core level spectra. A deconvolution procedure has been undertaken to determine quantitatively the [Cu2+]/[Cutotal] ratio. The non-bridging oxygen content, obtained from the deconvolution of the O 1s core level spectra, increases with increasing copper oxide content indicating that copper acts as a network modifier. The O 1s spectra were modelled in such a way as to separate the contribution from SiOCu and SiONa to the non-bridging oxygen signal.