An efficient green synthesis of ag/Fe2O3 nanocomposite using Carica Papaya peel extract for enhanced photocatalytic, antioxidant, and antibacterial activities

Abstract

Dye waste pollution poses a significant threat to human health and the environment. Photocatalysis can be used to degrade dyes in industrial wastes. This study aims to synthesize nanocrystals of Fe₂O₃ and Ag-doped Fe₂O₃ using Carica papaya linn peel extract as a reducing agent and ferric chloride hexahydrate and silver nitrate as precursors. The synthesized nanocrystals were investigated using UV–Vis, XRD, FT-IR, and SEM to confirm band shifts, crystallinity, functional groups, and morphological improvements. As a result, pure Fe₂O₃-NPs shifted their absorption band from 296 to 347 nm after incorporating Ag. In addition to the band shift, the energy bandgap was reduced from 3.34 to 2.91 eV as a result of the band shift. Based on the XRD patterns, Fe₂O₃-NPs have an average crystalline size of 26.72 nm, while Ag/Fe₂O₃ NCs have an average crystalline size of 29.17 nm. A highly enhanced photocatalytic performance was achieved with pristine Fe₂O₃-NPs due to Ag integration, and MB dye degradation was increased to 92.97 % from 72 %. Gram-positive and Gram-negative bacteria were killed by Ag/Fe₂O₃-NCs. The zone of inhibition for Ag/Fe₂O₃-NCs against B. cereus, S. aureus, S. typhi, and E. coli was estimated to be 19.5 mm, 19 mm, 18 mm, and 16.2 mm, respectively. Moreover, the nanomaterials' antioxidant activities were evaluated using a DPPH scavenging assay, with the IC50 values for the antioxidant activity of Ag/Fe₂O₃-NCs calculated to be 15.38 μg/mL. Based on these results, Ag/Fe₂O₃-NCs could be used as a useful photocatalyst for water treatment, pathogenic disinfection, and antioxidant tools.