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

Abstract The zircon-type phases, CeVO 4 , Ce 1− x M x VO 4−0.5 x (0≤ x ≤0.41 for M =Ca, 0≤ x ≤0.21 for M =Sr, and 0≤ x ≤0.1 for M =Pb) and Ce 1− y Bi y VO 4 (0≤ y ≤0.68), have been prepared in air by heating the stoichiometric mixture of CeO 2 , V 2 O 5 , CaCO 3 , SrCO 3 , PbO, and Bi 2 O 3 . 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 V 2 O 5 . All of these phases present high electrical conduction. In particular, the phases Ce 1− x M x VO 4−0.5 x ( M =Ca, Sr, and Pb) show excellently high values. The compound CeVO 4 is characterized as a p-type semiconductor by the Seebeck effect.