Green Synthesis of Gold Nanoparticles from Zingiber nigrum Leaves and their Efficacy in Photocatalytic Degradation of Toxic Dyes

Abstract

The environmental friendliness of plants and their extracts makes them essential for the green manufacturing of nanoparticles. Plant extracts have been used to create a variety of metal nanoparticles. In this work, we report on an environmentally friendly approach of producing gold nanoparticles by utilizing aqueous extracts of Zingiber nigrum (ginger) leaves and assess their photocatalytic properties. The produced nanoparticles' capacity for photocatalysis and antioxidants was also evaluated. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and UV-Vis spectrophotometry were used to analyze the gold nanoparticles (Zn-AuNPs) that were synthesised by Zingiber nigrum. Powder XRD measurements verified the Zn-AuNPs’ crystalline form. The Zn-AuNPs had an average particle size of 21.52 nm and were primarily spherical, according to micrographs obtained using high-resolution transmission electron microscopy (HRTEM). Polyphenolics and other functional groups that served as reducing and capping agents during the AuNP synthesis were discovered in the aqueous extract by FTIR spectral analysis. Significant antioxidant activity was demonstrated by these green-produced nanoparticles. The anthropogenic pollutant dyes methylene blue (MB) and rhodamine B (RhB) were catalyzed by Zn-AuNPs under UV radiation, with percent degradations of 93.25% and 97.64%, respectively. The photodegradation procedure adhered to a pseudo-first-order kinetic model. It has been suggested that the Zn on the Au nanoparticles effectively suppresses electron-hole recombination, which accounts for the observed photocatalytic activity of Zn-AuNPs. These findings support the notion that Zingiber nigrum is a viable bioresource for the production of gold nanoparticles with a wide range of environmental uses and is one of the novel features of this study.