green approach to synthesis of pt and bimetallic au@pt nanoparticles using carica papaya leaf extract and their characterization

This study reports a green approach to synthesis of monometallic platinum nanoparticles (pt nps) and bimetallic aurium@platinum nanoparticles (au@pt) using aqueous leaf extract of carica papaya as a reducing and stabilizing agent. the nature and morphology of as-synthesized ptnps and bimetallic au@pt nps were characterized using uv/vis spectroscopy (uv–vis), high resolution transmission electron microscopy (hrtem), fourier transform infrared spectroscopy (ftir), and energy dispersive x-ray (edx). hrtem images reveal that the as-synthesized ptnps are in the size range of 3.94–5.48 nm with average particle size of 4.50±0.80. the hrtem image of as-synthesized au@pt shows distinguishable objects of almost same spherical shape but having different contrast with size ranging from 4.17 to 13.23 nm and average particle size of 8.70±2.50 nm. the edx data of au@pt nanoparticles reflects bimetallic nature, and the individual metal of the bimetallic au@pt nanoparicles are present almost in the ratio 2:1. the narrow size distribution and small average size (< 10 nm) of the as-synthesized nanoparticles are highly potential in catalytic applications.