Biogenic synthesis of Co 3 O 4 nanoparticles from Aloe barbadensis extract: Antioxidant and antimicrobial activities, and photocatalytic degradation of azo dyes

The synthesis of Co 3 O 4 nanoparticles (NPs) through biogenic means offers a cost-effective, environmentally friendly, stable, versatile, and biocompatible approach. In this work, we employed Aloe barbadensis Miller leaf extract for the biosynthesis of Co 3 O 4 NPs, leveraging its rich composition of phenolic groups, polysaccharides, enzymes, minerals, vitamins, and various acids. The characterization of the synthesized NPs was performed using XRD, TEM, EDS, FT-IR, TGA-DSC, Raman, XPS, and particle size analysis techniques. Our investigation focuses on evaluating the antioxidant and antimicrobial properties of Co 3 O 4 NPs. Antioxidant activity was assessed through DPPH, ABTS, FRAP, and FICA assays, demonstrating the NPs ' ability to scavenge free radicals, reduce ferric ions, and chelate ferrous ions. Antimicrobial testing revealed the effectiveness of NPs against Proteus mirabilis and Staphylococcus aureus . Furthermore, biogenic Co 3 O 4 NPs were utilized as photocatalysts for the degradation of azo dyes (RhB, MB, and CV). Under sunlight exposure for 105 min, biogenic Co 3 O 4 NPs degraded CV dyes by 97.53%. The study also highlighted the remarkable efficiency of azo dye degradation across five cycles of reuse of biogenic Co 3 O 4 NP reuse.