Fig. 2From: Solar Hydrogen Production from Cost Effective Stannic Oxide Under Visible Light IrradiationSurvey XPS spectra (a), the Sn 3d XPS spectra (b), the O 1s XPS spectra (d) of SnO2 and prepared SnO2-x, and c the Sn 3d5/2 XPS spectra of prepared SnO2-xBack to article page