Highly Conductive Oxides, CeVO4, Ce1-xMxVO4-0.5x(M=Ca, Sr, Pb) and Ce1-yBiyVO4, with Zircon-Type Structure Prepared by Solid-State Reaction in Air

The zircon-type phases, CeVO4, Ce1-xMxVO4-0.5x (0x0.41 for M=Ca, 0x0.21 for M=Sr, and 0x0.1 for M=Pb) and Ce1yBiyVO4 (0y0.68), have been prepared in air by heating the stoichiometric mixture of CeO2, V2O5, CaCO3, SrCO3, PbO, and Bi2O3. During solid-state reaction, the spontaneous reduction of Ce(IV) to Ce(III) begins above 500°C and proceeds rapidly at about 666°C in conjunction with the melting of V2O5. All of these phases present high electrical conduction. In particular, the phases Ce1-xMxVO4-0.5x (M=Ca, Sr, and Pb) show excellently high values. The compound CeVO4 is characterized as a p-type semiconductor by the Seebeck effect.