Synthesis of Au, Ag and Au–Ag alloy nanoparticles in aqueous polymer solution

Gold, silver and gold–silver alloy nanoparticles were prepared under mild conditions using microwave heating, polyacrylamide as a stabilizing agent and hydrazine hydrate as a reducing agent. The UV–vis spectroscopy revealed the formation of silver and gold nanoparticles by exhibiting surface plasmon absorption maxima at 410 and 548 nm, respectively. For Au–Ag bimetallic particles the surface plasmon absorption maxima appeared in between the peaks corresponding to pure silver and pure gold. The surface plasmon absorption maxima for bimetallic nanoparticles changes linearly with increasing gold content in the alloy. Transmission electron micrograph (TEM) showed presence of spherical particles in the range of 5–50 nm size.