Plasmonic effects and size relation of gold-platinum alloy nanoparticles

Plasmonic effects of gold and platinum alloy nanoparticles (Au-Pt NPs) and their comparison to size was studied. Various factors including ratios of gold and platinum salt, temperature, pH and time of addition of reducing agent were studied for their effect on particle size. The size of gold and platinum alloy nanoparticles increases with increasing concentration of Pt NPs. Temperature dependent synthesis of gold and platinum alloy nanoparticles shows decrease in size at higher temperature while at lower temperature agglomeration occurs. For pH dependent synthesis of Au-Pt nanoparticles, size was found to be increased by increase in pH from 4 to 10. Increasing the time of addition of reducing agent for synthesis of pure and gold-platinum alloy nanoparticles shows gradual increase in size as well as increase in heterogeneity of nanoparticles. The size and elemental analysis of Au-Pt nanoparticles were characterized by UV-Vis spectroscopy, XRD, SEM and EDX techniques.