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 groupPnma (62) with a = 5.5181 (3), b = 7.7853 (2) and c = 5.5155 (4) Å for Ce0.85Sr0.15VO3. Conductivity measurements were performed in air and in dry 5% H2–Ar with conductivity values at 700 °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.