Green Synthesis of Selenium Nanoparticles from Nephelium lappaceum L. Seeds (NL-SeNPs) for Antioxidant and Photocatalytic Applications

Selenium nanoparticles (SeNPs) have acquired significant interest owing to their distinctive physicochemical characteristics and broad spectrum of application possibilities. In this study, SeNPs were synthesized using Nephelium lappaceum L. (NL) seed extract and assessed for both antioxidant and photocatalytic capabilities. The successful synthesis of NL-SeNPs was designated by a noticeable color shifting from yellow to red and validated by a UV–Vis absorbance peak at 263 nm. FTIR studies confirmed the existence of functional groups representative of various chemical compounds, including phenols and amines, which likely contributed to the reduction and stabilization of NL-SeNPs. The produced NL-SeNPs had a spherical morphology with an average particle size of approximately 100.94 nm and demonstrated notable colloidal stability, as indicated by a zeta potential of –30.7 mV. Their antioxidant activity showed moderate free radical scavenging efficiency in comparison to ascorbic acid, with maximum inhibition rates of 47.62% and 40.67% at a concentration of 70 µg/mL, and IC₅₀ values of approximately 95.25 µg/mL and 112.44 µg/mL in the DPPH and ABTS assays, respectively. Furthermore, the photocatalytic performance of NL-SeNPs significantly enhanced the degradation of methylene blue, achieving approximately 69.40% removal after three hours under 365 nm UV irradiation. These findings show that NL-SeNPs work both as antioxidants and photocatalysts, making them useful for medical uses and eco-friendly cleaning or treatment processes.