Photocatalytic and biological efficacy of Carissa macrocarpa fruit extract-mediated one-pot synthesized ternary metal oxide dual S-scheme heterojunction

Abstract

Photodegradation of organic pollutants on the surface of greenly synthesized nanomaterials under sunlight irradiation is a viable approach for water purification. Since a little attention has been paid to the green synthesis of ternary nanocomposites, therefore current work has been designed to greenly synthesized dual S-scheme heterojunction using aqueous extract of Carissa macrocarpa fruit. After successful characterization by UV-Visible spectroscopy (UV-Vis.), Fourier-transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), scanning electrode microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), high-resolution transmission electron microscopy (HR-TEM), Thermogravimetric analysis (TGA), dynamic light scattering (DLS), and zeta potential analysis (ZP), Thermogravimetric analysis and X-ray photoelectron spectroscopy (XPS), the stable nanocomposite was evaluated for its catalytic potential for the photodegradation of three azo dyes, i.e., methylene blue (MB), Congo red (CR), and methyl orange (MO), under sunlight. 91 %, 97 %, and 85 % degradation with rate constant values of 2.03×10−2 min−1, 2.83×10−2 min−1, and 1.64×10−2 min−1 were observed for MB, CR, and MO, respectively, in just 120 minutes of exposure to sunlight. Effect of radical scavengers and flat band positions of NCs were evaluated to propose the mechanism and transfer of electrons and holes to decompose the dyes. The reusability of the catalyst was assessed for five consecutive cycles, which showed only a slight reduction (∼1.09%) in its activity. In addition to their photocatalytic potential, the aqueous extract and the greenly synthesized nanocomposite were also evaluated for their antibacterial potential by the disc diffusion method.