X-ray photoelectron spectroscopy and ion dynamics study of W6+ doped La2Mo2O9 as SOFC electrolyte

Abstract

The structural stability of La2Mo2-xWxO9 is well reported by many researchers but its studies on photoelectron spectroscopy, structural behaviour in Ar-H2 (reducing) atmosphere and ion dynamics are rarely reported. Here we report for the first time, to the best of authors’ knowledge, the above studies for W-doped La2Mo2O9 compounds. La2Mo2O9 doped with W6+ over the range of 0.25 ≤ x ≤ 1.75 at Mo6+ site is synthesised by solid-state reaction route. The x-ray diffraction studies show that at x = 0.5 the lattice parameter of the unit cell starts decreasing as a consequence of decrease in bond length between various elements present in the compound. The XPS analysis shows that Mo in La2Mo2-xWxO9 is very much sensitive to reduction. The temperature dependent a.c. impedance spectroscopy study of La2Mo2-0.5W0.5O9 has been reported over the temperature range up to 653 K. © 2018 Elsevier Ltd