Study of the synthesis and characterization of platinum and platinum-gold nanoparticles using some plants extract

Abstract

Scaling down objects to the nanometre size frequently leads to physical properties differing from those of the macroscopic counterparts. This effect is, on the one hand, due to the large specific surface of the nanoparticles, which makes them, for example, more chemically reactive than the bulk materials. The techniques for obtaining nanoparticles using naturally occurring reagents such as plant extracts, biodegradable polymers, and microorganisms as bio-reductants and capping agents could be considered attractive for nanotechnology. Plant based materials seem to be the best candidates and they are suitable for large-scale ‘biosynthesis’ of nanoparticles. In the plant-based biosynthesis, green and rapid synthesis of metal NPs could be achieved. Furthermore, they provide an environmentally friendly or greener chemical method to produce invaluable materials because the routes eliminate the need to use harsh or toxic chemicals. In this work, three plant extracts namely green tea leaves mentha leaves (mint) and thyme were used to sensitize Pt and bimetallic PtAu nanoparticles. The nature of both PtNPs and PtAuNPs were characterized using UV/vis spectroscopy (UV–vis), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA) and energy dispersive X-ray (EDX). TEM images of the nanoparticles using the three plants revealed that the biosynthesis of PtNPs were in the size range of 2–4 nm and the bimetallic PtAuNPs in the size range of 10-40 nm and both were crystallized in face centered cubic symmetry. Photocatalytic degradation property of Pt and Pt-Au nanoparticles was investigated by degradation of Methylene blue dye under UV light irradiation. The results show that PtNps has higher activity of degradation of Methylene blue than PtAuNPs. On the other hand, photocatalytic degradation of Methylene blue dye using Pt and PtAuNps supported on TiO2 was studied. Keywords: Biosynthesis, Platinum nanoparticles (PtNPs), Pt-Au NPs, photocatalysis.