Abstract
The development of efficient visible-light-responsive photocatalysts is essential for the sustainable remediation of water contaminated with persistent organic pollutants. In this work, BiAlO₃ perovskite was investigated as a pristine photocatalyst for the first time for the visible-light-driven degradation of Rhodamine B (RhB). The synthesized material exhibited a well-crystallized rhombohedral perovskite structure, while electron microscopy revealed irregularly aggregated particles composed of nanoscale structural features. Surface chemical analysis confirmed the presence of Bi³⁺, Al³⁺, and oxygen species. Optical characterization revealed an optical band gap of approximately 2.7 eV, together with pronounced energy-dependent dielectric, conductivity, and charge-relaxation responses, indicating favorable light–matter and charge-dynamic characteristics. Under visible-light irradiation, BiAlO₃ achieved 87.54% RhB degradation within 90 min, compared with only 9.63% removal by direct photolysis, demonstrating its intrinsic photocatalytic activity. Scavenger experiments revealed that photogenerated holes and hydroxyl radicals make the dominant contributions to RhB degradation, followed by photogenerated electrons and superoxide radicals, with an approximate contribution order of h⁺ > •OH > e⁻ > •O₂⁻. The photocatalyst also retained approximately 75% degradation efficiency after six consecutive cycles, demonstrating good operational stability and reusability. The combination of a relatively narrow band gap, favorable optical and charge-dynamic characteristics, efficient visible-light photocatalytic activity, and satisfactory cycling stability highlights BiAlO₃ as a promising lead-free perovskite photocatalyst for organic pollutant remediation. More broadly, this work establishes the previously unexplored BiAlO₃/RhB photocatalytic system and provides new insight into the relationship between the intrinsic optical and charge-dynamic properties of BiAlO₃ and its photocatalytic performance.