Synthesis, Characterization, and Evaluation of Zero‐Valent Iron Nanoparticles from Different Leaf Extracts: Photo‐Catalytic Dibenzothiophene Degradation and Antimicrobial Efficiency

Abstract A simple, efficient green synthesis approach was employed to produce efficient and potential iron‐zero valent photocatalysts (Fe0 NPs), derived from two plant extracts: Rosmarinus officinalis (ROS‐Fe0 NPs) and Guava leaves (GUA‐Fe0 NPs). These nanocatalysts were tested for the photo‐degradation of dibenzothiophene (DBT), and their antimicrobial properties were also assessed. The biosynthesized Fe0 NPs characterized via different techniques. XRD revealed two diffraction peaks of lattice planes (110), and (200), corresponding to body‐centered cubic (bcc) structure of metallic Fe0. The lower PL intensity of ROS‐Fe⁰ NPs compared to GUA‐Fe⁰ NPs suggests reduced electron‐hole recombination, leading to improved photocatalytic activity. The ROS‐Fe⁰ NPs achieving 89.9% DBT degradation compared to 80% for GUA‐Fe⁰ NPs. This is due to ROS‐derived phytochemicals, such as polyphenols and flavonoids, which act as capping agents, improving nanoparticle dispersion, and reducing size. After five cycles, Fe0 NPs converted into hematite and magnetite phases enhances the photocatalytic degradation of DBT up to 95.6% for spent oxidized ROS‐Fe0 NPs and 90.3% for spent oxidized GUA‐Fe0 NPs. Both plant extracts and their corresponding iron nanoparticles (Fe0 NPs) demonstrated strong antimicrobial activity against bacteria and fungi. So, the phytochemicals derived from GUA‐ and ROS‐ highlight their influence on both photocatalytic and antibacterial performance.