Sustainable Synthesis of ZnO–CuO Bimetallic Nanoparticles by Pelargonium Graveolens Extract for Catalytic Synthesis of 1,2,4‐Triazolidine‐3‐Thione and Antimicrobial Applications

ABSTRACT This study reports the green synthesis of bimetallic ZnO–CuO nanoparticles using an aqueous extract of Pelargonium graveolens leaves, which acts as both a bioreductant and a stabilizing agent. The synthesized nanoparticles exhibited an average particle size of 23.8 nm, as determined by XRD analysis. Comprehensive characterization was carried out using SEM, XRD, EDX, TGA, UV–vis spectroscopy, and FTIR, confirming the crystalline structure, elemental composition, thermal stability, and surface functional groups of the nanomaterials. The resulting ZnO–CuO nanocatalyst was applied to the one‐pot synthesis of 1,2,4‐triazolidine‐3‐thione derivatives. The protocol afforded excellent product yields (86%–96%) within 30–32 min, demonstrating high catalytic efficiency. The catalyst also exhibited robust reusability, retaining over 85% of its catalytic activity after five successive cycles. Furthermore, the system displayed high turnover number (TON) values of up to 11,682.82 and turnover frequency (TOF) values reaching 22,931.89 h −1 , indicating its strong performance in catalytic transformations. Antimicrobial assays revealed notable inhibitory activity of the synthesized nanoparticles against both Gram‐positive ( Staphylococcus aureus ) and Gram‐negative ( Escherichia coli ) strains, with inhibition zones measuring 15.6–32.1 mm. The integration of a renewable, plant‐based extract, mild reaction conditions, and a recyclable catalytic material highlights the green and sustainable nature of this methodology.