Visible-light sensitization and recombination delay through coupling CaFe₂O₄ on Bi₂O₃ nanocomposite for high performance photocatalytic and antibacterial applications

The development of Bi₂O₃ based advanced photocatalytic materials has seen a momentous leap in recent decades. However, pure Bi₂O₃ suffers rapid e⁻/h⁺ pair recombination rate and low visible light response. To improve its photocatalytic performance, CaFe₂O₄-Bi₂O₃ nano-heterojunction was constructed using ultrasonic assisted chemical co-precipitation method. The morphological analysis depicted the decoration of spherical CaFe₂O₄ on sheet-like Bi₂O₃ nanoparticles (NPs) surface. The interface in nanocomposites (NCs) promotes migration of charge carriers and improves its life time that was verified using photoluminescence study. The elemental composition of NCs was verified using XPS and EDAX. The photon absorption ability of NCs in visible region was favored by the energy bandgap of 2.16 eV. The NCs exhibited 8 to 16 fold increase in kinetic rate constant than Bi₂O₃ and CaFe₂O₄ for the methylene blue (MB) dye degradation. The dominant reactive oxygen species (ROS) in photodegradation process was found to be hydroxyl radicals (OH.). The NCs was magnetically recoverable with high reusable capacity. The multifunctionality of NCs as antibacterial agents was also investigated. The NCs greatly inhibited the growth of Escherichia coli and Bacillus subtilis. The current investigation provides a promising approach for photodegradation and bacterial inactivation by improved performance of CaFe₂O₄-Bi₂O₃ NCs.