Bio‐Fabricated Silver Nanoparticles for Catalytic Degradation of Toxic Dyes and Colorimetric Sensing of Hg ²⁺

Abstract In the present study, silver nanoparticles were synthesized via green synthesis using fenugreek ( Trigonella foenum‐graecum L.) seeds of variety HM 425. The AgNPs were characterized by using UV‐Visible spectroscopy, Particle size analyzer, Field emission scanning electron microscopy coupled to Energy dispersive X‐ray spectroscopy, XRD, High resolution transmission electron microscopy and Fourier Transform Infrared Spectroscopy. The AgNPs were spherical and had an average particle size of 28 nm. The reduction of cationic dyes Methylene blue, Rhodamine B, and an anionic azo dye Methyl Orange by Sodium borohydride was used as a model reaction to investigate the catalytic ability of AgNPs. The results demonstrated an efficient catalytic dye degradation of methylene blue (95.81 %, 25 min, 0.1737±0.01 min −1 ), Rhodamine B (90.23 %, 15 min, 0.1388±0.01 min −1 ) and methyl orange (83.63 %, 39 min, 0.0412±0.002 min −1 ). The synthesized AgNPs had an excellent detection limit of 12.50 μM for Hg 2+ , making them excellent solid bio‐based sensors for mercury sensing.