Structural, optical, and photocatalytic properties of rare-earth free double-perovskite oxides Ba2Bi3+(Bi1−2x5+Sb2x5+)O6

We present the structural, optical, and photocatalytic properties of rare-earth free double-perovskite compounds Ba2Bi3+(Bi1−2x5+Sb2x5+)O6 (x= 0, 0.1, 0.2, 0.3, 0.4, and 0.5). All samples prepared by the solid-state reaction method were formed in the single-phase monoclinic and rhombohedral perovskite oxides. Using the First Principle calculations of density functional theory, the effect of Sb substitution on band gap broadening was examined and a reasonable correlation was found with the experimental results. The photocatalytic activities were studied from the MB and IPA decomposition experiment. It was observed that Ba2Bi3+(Bi1−2x5+Sb2x5+)O6 exhibited better MB degradation performance under Sb substitution accompanied by the formation of nanoparticles. IPA decomposition result supports this finding and suggested that smaller particles in the Sb substituted samples reasonably affect the CO2 evolution performance.The maximum MB decomposition rate (about 50%) was found for the 20% Sb-incorporated sample. In contrast to the previously reported rare-earth-based double perovskite photocatalyst, a comparable performance was obtained in this research. The excellent surface morphology associated with the smaller particle sizes and better crystallinity for the Sb substituted sample promoted more active sites that facilitated improved photocatalytic activities of Ba2Bi3+(Bi1−2x5+Sb2x5+)O6 double perovskite.