Biosynthesis of magnetic ZnO@FeO nanocomposites decorated with Ag/AgCl using Hormoz Island's red soil and Avicennia marina leaf extract.

The development of environmentally sustainable and non-toxic visible-light (VL) sensitive nanostructured photocatalysts is a significant focus in nanotechnology, necessitating safe synthesis techniques for these nanocomposites. This study introduces a straightforward and low-temperature biosynthesis process using leaf extract from the Avicennia marina mangrove (MTLE) and red soil from Hormoz Island, Iran to produce Ag/AgCl-decorated magnetic ZnO@FeO, a plasmonic triple heterojunction nanocomposite (NC). The biosynthesized Ag/AgCl/ZnO@FeO magnetic NC (BSNC) exhibited a particle size of ~ 60 nm, a magnetization of 8.04 emu.g, and a band gap energy (Eg) of 1.3 eV, optimized at an MTLE concentration of 0.5 g·100 mL. The concentration of MTLE significantly influenced the properties of the products, acting as a reducing and stabilizing agent. As MTLE concentration increased from 0.125 to 0.5 g·100 mL, VL light absorption intensity improved, alongside changes in Eg, suggesting an optimal concentration for enhanced photocatalytic activity. The BSNC demonstrated a broad absorption peak between 400 and 600 nm, attributed to surface plasmon resonance and electron dynamics involving Ag/AgCl and ZnO. This biosynthetic approach offers an eco-friendly alternative for producing Ag/AgCl/ZnO@FeO plasmonic NCs with improved VL photo-activity.