Unveiling an Energy Efficient Solar-Driven Nanophotocatalyst: Z-Scheme-Based CdFe2O4@CuBi2O4 Heterostructure for MB and RhB Dye Degradation

We developed a Z-scheme-based CdFe2O4@CuBi2O4 nanocomposite for efficient photocatalytic degradation of methylene blue (MB) and Rhodamine B (RhB) dyes under visible light. The Z-scheme heterojunction was meticulously constructed by integrating CuBi2O4 and CdFe2O4 nanoparticles with varying mass ratios. The photocatalytic degradation experiment revealed that 98.48% of the MB dye was degraded in 80 min, whereas 98.70% of the RhB dye was degraded in 70 min. The nanocomposite's enhanced photocatalytic activity and stability can be attributed to the synergistic effect of intimate heterogeneous interfacial contacts, which facilitated the separation and transfer of charge carriers, broadened the light absorption range, and boosted the redox ability of the photocatalyst. It involved direct oxidation by holes and indirect oxidation by reactive oxygen species (ROS), such as hydroxyl and superoxide radicals. The photocatalytic rate of reaction for the 20%-CdFe2O4@CuBi2O4 nanocomposite was observed to be 0.0516 min–1, which was 2.38 and 3.0 times higher than the pure CuBi2O4 (0.0216 min–1) and CdFe2O4 (0.0169 min–1), respectively. The developed nanocomposite showed a good photolytic performance in binary dye solutions of different concentrations and reusability for at least four cycles. It also achieved satisfactory results in tap water (98.33%), river water (95.82%), and wastewater (86.12%). This study highlights the potential of a synthesized nanocomposite as an energy-efficient photocatalyst for degrading MB and RhB dyes from wastewater under visible light.