Novel redox reversible oxide, Sr-doped cerium orthovanadate to metavanadate

Abstract

A-site substituted cerium metavanadates, Ce1-xSrxVO3, were synthesised by solid-state reactions from single-phase powders of the corresponding orthovanadates. All samples were found to exhibit an orthorhombic perovskite structure of space group Pnma (62) with a = 5.5181 (3), b = 7.7853 (2) and c = 5.5155 (4) angstrom for Ce0.85Sr0.15VO3. Conductivity measurements were performed in air and in dry 5% H-2-Ar with conductivity values at 700 degrees C ranging from 0.1 to 2.5 S cm(-1) with peaking at 6 S cm(-1) in reduced atmosphere. X-Ray diffraction patterns and thermal analyses have shown that the reduction of Sr-doped CeVO3 from the equivalent orthovanadate is redox phase reversible without formation of parasitic phases while the undoped CeVO4 is not

H2 and CH4 oxidation on Gd0.2Ce0.8O1.9 infiltrated SrMoO3–yttria-stabilized zirconia anode for solid oxide fuel cells

“…Ni oxidation could cause up to 69.2% volume expansion [33], which is more severe than 28% volume change upon the reduction of SrMoO 4 to SrMoO 3 [34]. Sr-doped CeVO 3 [35] and Ca-doped CeVO 3 [36] have different redox reversibility for different amount of doping. In this study, redox cycling stability of the GDC infiltrated SrMoO 3 eYSZ anode was examined at 900 C on a single cell under wet H 2 .…”

Solid Oxide Fuel Cell Anode Materials for Direct Hydrocarbon Utilization

“…[ 365 ] Another approach to mitigate the redox instability problem focuses on ortho-and pyro-vanadates which are by themselves stable in oxidizing atmospheres, such as FeVO 4 , [ 366 ] Co 2 V 2 O 7 , [ 367 ] , Ce 1− x Ca x VO 4 , [ 368 ] and Ce 1− x Sr x VO 4 . [ 362 ] The underlying methodology is to make these vanadates also stable in reducing environment. Ce 0.9 Ca 0.1 VO 4 and Ce 0.8 Ca 0.2 VO 4 of zircon structure were found to be redox stable at temperatures lower than 600 ° C, though the electrical conductivity was still low (Table 4 ).…”

Conductivity and stability of cobalt pyrovanadate

“…In general, vanadium containing compounds are of interest as anode materials due to their high catalytic activity [13] and the possibility of metallic-type conduction upon reduction [11,14].…”