Facile fabrication of CaAl2O4/Bi2O3: A direct Z-scheme photocatalyst for enhanced photocatalytic degradation of congo red and enrofloxacin

Due to the increasing presence of organic pollutants such as dyes and antibiotics in water bodies, there is a pressing need for efficient and sustainable remediation strategies. In this study, a novel CaAl₂O₄/Bi₂O₃ composite photocatalyst was successfully synthesized via a straightforward solid-state grinding method of the individual parent materials. The close interface between CaAl₂O₄ and Bi₂O₃ facilitated direct Z-scheme heterojunction formation, enhancing charge separation while preserving strong redox potential for reactive oxygen species generation. The catalyst demonstrated excellent degradation performance against both congo red dye and enrofloxacin antibiotic under UV and visible light irradiation. Specifically, the composite achieved a degradation efficiency of 96.5 % for congo red within 90 min and 82.6 % for enrofloxacin within 180 min. Trapping experiments identified superoxide radicals and holes as the primary reactive species responsible for pollutant degradation. The catalyst exhibited robust activity across different pollutant types, underscoring its versatility and potential for practical wastewater treatment. These findings provide valuable insights into the rational design of direct Z-scheme photocatalysts through simple synthesis routes and highlight the composites promise for addressing complex environmental contamination.