Oxygen‐Deficient R₂MoO_6–δ (R = Tb, Dy, Y, Ho, Er, Tm, Yb) with Fluorite Structure as Potential Anodes in Solid Oxide Fuel Cells

Abstract

The members of the family of oxygen-defective fluorites R 2 MoO 6-δ (R = Tb, Dy, Y, Ho, Er, Tm, Yb) have been synthesized under reducing conditions and characterized in order to evaluate their potential use as anodes in intermediatetemperature solid oxide fuel cells (IT-SOFCs). A neutron powder diffraction (NPD) investigation demonstrates that they are all cubic, in the Fm3m space group, exhibiting a random distribution of R and Mo cations over the metal sites of the fluorite structure with crystallographic formula MO 2-δ/3 (M = R 2/3 Mo 1/3 ), Z = 4. These materials are highly oxygen-deficient fluorites with oxygen stoichiometries ranging from 5.2(1) (R = Y, Tm) to 4.8(1) (R = Tb, Dy, Ho, and Er) oxygen atoms per formula unit, accompanied by high values of the displacement parameters at room temperature (ca.

Investigation of the Heterovalent Substitution Cadmium for Lanthanum in Molybdate La2MoO6

“…e cubic molybdates Ln 2 MoO 5 with fluorite structure for Ln � Gd, Tb, Dy, Ho, and Y were prepared by reduction of Ln 2 MoO 6 with hydrogen [12]. In recent years due to increased interest in ionic oxygen conductors with high conductivity at medium temperatures (200-900°S), compounds Ln 2 MoO 6-δ with fluorite structure, where Ln � Tb-Yb, were studied in the systems Ln 2 O 3 -MoO 3 [13].…”

Synthesis, Structure Refinement and Conductivity of Ln_2-xCd_xMoO_6-x/2

“…In addition to these, there are also compounds Ln 2 MoO 6 (Ln -lanthanide) [8]. Promising solid electrolytes Ln 2 MoO 6-δ with fluorite structure which have high electro-ionic conductivity were obtained using Mo +6 reduction into lower oxidation states [9]. Evidently, its disadvantage is low stability in oxidation atmosphere.…”