Bi₂O_2.33/Bi₄O₅I₂-heterojunction photocatalysts for adsorption and visible light-driven degradation of pharmaceutical pollutants

This study introduces the innovative Bi₄O₅I₂/Bi₂O_2.33 heterojunction for diclofenac (DF) degradation. Pharmaceutical pollutants, especially DF, pose significant threats to water sources, necessitating efficient treatment methods. Bi₂O_2.33, renowned for its unique ferromagnetic properties, emerges as a promising photocatalyst for pollutant degradation. Bi₄O₅I₂, known for strong visible light absorption and stability, holds potential for environmental applications. Interestingly, the inclusion of titanium dioxide (TiO₂) in the composite catalysts significantly influences their observed ferromagnetic properties, as revealed by Electron Paramagnetic Resonance (EPR) spectroscopy, by influencing the interactions within the Bi₄O₅I₂/Bi₂O_2.33 heterojunction and influencing its structure, morphology, and spin behavior. This interaction results in enhanced EPR and Ferromagnetic Resonance (FMR) signals, indicating intriguing spin interactions, polarization effects, charge transfers, surface dynamics, and stabilized magnetic domains. While the enhanced ferromagnetism holds promise for efficient charge separation and potential applications in environmental remediation, the expected boost in visible light-driven activity was not fully realized. This limitation is attributed to TiO₂ inherent inability to directly absorb visible light, hindering its utilization for enhanced photocatalysis within the heterojunction. Nevertheless, these findings elucidate the multifaceted role of TiO₂ in modulating the magnetic properties of these catalysts, offering valuable insights for future advancements in the design of advanced photocatalysts for effective environmental remediation.