Preparation, characterization and environmental applications of Sr1 - x (La,Bi) x TiO3 perovskites immobilized on Ni-foam: photodegradation of the Acid Orange 7

Abstract

The Sr_{1 - x} La _x TiO₃ (0 ≤ x ≤ 0.4) and Sr_{1 - x} Bi _x TiO₃ (0 ≤ x ≤ 0.3) perovskites were prepared via solid state reaction by partially replacing the Sr²⁺ ions in the SrTiO₃ structure by La³⁺ or Bi³⁺ ions, characterized and utilized as photocatalysts immobilized in Ni-foam substrate in the degradation of the azo dye Acid Orange 7 (AO7). For both perovskite families, the XRD data reveal the existence of a predominant well-crystallized phase, belonging to a cubic perovskite in a Pm3m space group, with the presence of other minority phases. The characteristic dimension and the volume of the cell decrease with the introduction in the SrTiO₃ lattice of the La³⁺ or Bi³⁺ ions. The grain size of the Sr_{1 - x} La _x TiO₃ samples is around 100 nm and slightly lower for the Sr_{1 - x} Bi _x TiO₃ samples. Regarding the utilization of the prepared perovskite powders deposited over the Ni-foam substrates as catalysts in the photodegradation of AO7 solutions, the results show an improvement in the performance of the films of the substituted perovskite when compared to the SrTiO₃ perovskite, being the best results obtained with Sr_0.9Bi_0.1TiO₃.

Keywords: AO7; Perovskite; Photodegradation; Sr1 − x Bi x TiO3; Sr1 − x La x TiO3.