Structural, physical and photocatalytic properties of mixed-valence double-perovskite Ba2Pr(Bi,Sb)O6 semiconductor synthesized by citrate pyrolysis technique

Abstract

We demonstrated crystal structures, magnetic, optical, and photocatalytic properties of the B-site substituted double perovskite Ba2Pr(Bi1–xSbx)O6 (x = 0, 0.1, 0.2, 0.5 and 1.0) synthesized by the citrate pyrolysis method. The single-phase polycrystalline samples with the light Sb substitution crystallized in a monoclinic structure (I2/m). Magnetization measurements on all the samples showed that the effective magnetic moments are concentrated around 3 μB, indicating the valence mixing states between Pr3+ and Pr4+. The magnitudes of band gap energy for the two end member samples were estimated from the optical measurements to be Eg = 1.06 eV at x = 0 and 2.71 eV at x = 1.0. The Ba2Pr(Bi1–xSbx)O6 (x = 0, and 0.1) powders obtained by the present technique exhibited enhanced photocatalytic activities when compared to the same compounds prepared by the conventional solid state method. Our findings suggest that the higher photocatalytic activities strongly depend on powder preparation methods as well as the band gaps and photogenerated charge separation.