Green Synthesis of Spinel Fe ₃ O ₄ /Co ₃ O ₄ Nanocomposite as an Efficient Nanophotocatalyst for the Degradation of Toxic Organic Dyes Under Natural Sunlight

The coupling strategy has enhanced the photocatalytic efficiency of the Fe 3 O 4 and Co 3 O 4 nanoparticles, resulting in a spinel nanocomposite that exhibits significant magnetic, electrical, optical, and catalytic properties, which addresses the increasing demand for effectiveness of nanomaterials in pollution control, driven by environmental concerns related to organic pollutants from population growth and industrial expansion. Under this study, Fe 3 O 4 , Co 3 O 4 NPs, and Fe 3 O 4 /Co 3 O 4 NCs were synthesized through the green method using B. spectabilis flower extract. XRD, SEM, FT‐IR, and UV–Vis were applied to characterize the synthesized nanomaterial. From XRD data, the average particle size was found to be 27.68 nm for Fe 3 O 4 NPs, 20.78 nm for Co 3 O 4 NPs, and 18.85 nm for Fe 3 O 4 /Co 3 O 4 NCs, which reveal crystallinity in nature within nanosized. The formation of Fe 3 O 4 NPs and Co 3 O 4 NPs was demonstrated by FT‐IR spectra with the characteristic peak of Fe–O bending vibration at 484 cm −1 and Co–O bending vibration at 642 and 558 cm −1 . The optical study through UV–visible confirmed the synthesis of spinel Fe 3 O 4 /Co 3 O 4 NCs with a narrow band gap energy (1.56 eV) by coupling Co 3 O 4 NPs (2.17 eV) and Fe 3 O 4 (1.68 eV). The SEM result shows that the Fe 3 O 4 , Co 3 O 4 NPs, and Fe 3 O 4 /Co 3 O 4 NCs are rough, moderately smooth, and sponge‐like particles with random‐oriented pores, voids, and closely packed irregular granular structures. In the photodegradation study, high efficiencies of 92.73%, 90.03%, and 98.11% for CR and 90.27%, 86.12%, and 95.01% for MG on the surface of Fe 3 O 4 NPs, Co 3 O 4 NPs, and Fe 3 O 4 /Co 3 O 4 NCs, respectively, were achieved at optimal condition. The Fe 3 O 4 /Co 3 O 4 NCs exhibited superior performance, achieving degradation 98.11% of CR and 95.01% of MG, due to the synergistic heterojunction formation between Fe and Co oxides, which improves charge separation and prolongs electron–hole lifetimes results, resulting in enhanced photocatalytic performance. Overall, the biosynthesized Fe 3 O 4 , Co 3 O 4 NPs, and Fe 3 O 4 /Co 3 O 4 NCs present an effective, cost‐effective, and eco‐friendly solution for the photocatalytic degradation of pollutant dyes. Future researchers are encouraged to explore the potential of this spinal photocatalysts for the production of solar‐driven green chemical fuels.