Surface chemical composition of MV10Mo2O31 center dot nH(2)O (M= Na-2, K-2, Ca, Sr, Cu) xerogels

X-ray photoelectron spectroscopy and thermal desorption spectrometry was us ed to study the chemical composition of the MV10Mo2O31. nH(2)O (M=Na-2, K-2 , Ca, Sr, Cu) xerogels. The binding energy, FWHM and shape of the main XPS peaks were analysed. The valency of the vanadium ions was studied. The conc entration ratio of tetra- and pentavalent vanadium ions N=V+4/(V+4+V+5), wh ich is an important parameter, deciding the electronic part of total conduc tivity, was determined from the peak fitting of the V 2p(3/2) line. The the rmal desorption measurements were performed at the temperatures up to 550 d egrees C; afterwards the samples in the dehydrated state were studied again by XPS. (C) 2000 Elsevier Science B.V. All rights reserved.