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 Fe 2 O 3 and Ag-doped Fe 2 O 3 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 Fe 2 O 3 -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, Fe 2 O 3 -NPs have an average crystalline size of 26.72 nm, while Ag/Fe 2 O 3 NCs have an average crystalline size of 29.17 nm. A highly enhanced photocatalytic performance was achieved with pristine Fe 2 O 3 -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/Fe 2 O 3 -NCs. The zone of inhibition for Ag/Fe 2 O 3 -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/Fe 2 O 3 -NCs calculated to be 15.38 μg/mL. Based on these results, Ag/Fe 2 O 3 -NCs could be used as a useful photocatalyst for water treatment, pathogenic disinfection, and antioxidant tools. • Ag incorporated Fe 2 O 3 -NPs synthesized using Carica papaya linn peel extract as a reducing agent. • The Eg of the pure Fe 2 O 3 -NPs decreased from 3.34 eV to 2.91 eV due to Ag integration. • Enhanced photocatalytic, efficiency and antibacterial and antioxidant activities were observed following the Eg reduction. • Ag/Fe 2 O 3 nanocomposites (NCs) were highly effective in reducing harmful microorganisms and minimizing environmental contamination.