Ultrafast fluorescent detection of hexavalent chromium ions, catalytic efficacy and antioxidant activity of green synthesized silver nanoparticles using leaf extract of P. austroarabica

Abstract

The wrapping of silver nanoparticles (AgNPs) with a biocompatible matrix to gain AgNP colloids, is a promising strategy to synthesize the AgNPs for numerous applications. In this work, an aqueous leaf extract of P. austroarabica plant has been utilized to produce highly active AgNPs and study the metal sensing, catalytic, and antioxidant activities of these nanoparticles. It has been observed that the phytochemicals in the P. asutroarabica plant reduced Ag+ to silver nanoparticles and acted as capping and stabilizing agents. The biosynthesized silver nanoparticles were characterized using various techniques such as UV–Vis, FTIR, PXRD, SEM, EDAX, TEM, and fluorescence spectroscopy. According to PXRD, SEM, and TEM analysis, the biosynthesized AgNPs were spherical face-centered-cubic (FCC) crystals with an average particle size of 16.8 ± 5.4 nm. The biosynthesized silver nanoparticles were examined for the fluorescent detection of Cr(VI), catalytic efficacy towards the degradation of organic dyes, and their antioxidant activities. The fluorescence technique proved that the biosynthesized silver nanoparticles are an excellent and efficient probe for Cr (VI) ions with LOD i.e. 1.15 nM, which is one of the lowest detection limits for sensor materials reported thus far. The results also demonstrated that the green synthesized AgNPs are highly efficient nano-catalyst for decomposing organic dyes, achieving 96.79 % and 95.63 % decolorization of methylene blue and Congo red dyes within 9 and 6 min, respectively. Additionally, the antioxidant activity assay results indicated that biosynthesized silver nanoparticles had excellent antioxidant activity when compared with ascorbic acid, because of the presence of bioactive molecules on the AgNPs surface. So, AgNPs may be employed as antioxidants in future due to being extremely effective, non-toxic, eco-friendly, and inexpensive. Therefore, this work will open a new window for the production and use of these AgNPs on wide-scale in various fields.