X-ray photoelectron spectroscopy was used to study the chemical composition
and valence states of the metal ions in vanadium-yttrium. hydrate. The bin
ding energies, FWHM and shape of the main XPS peaks were analyzed. The conc
entration ratio of tetra- and pentavalent vanadium ions C=V4+ /(V4+ +V5+),
which is an important parameter, deciding the electronic part of total cond
uctivity, was determined before (C=0.14) and after heating at 720 K (C=0.28
). (C) 2001 Elsevier Science BY All rights reserved.