A one-pot synthesis of colloidal Ag–Au nanoparticles with controlled composition

摘要： We report a one-pot synthesis method for a production of a stable Ag–Au bimetal colloidal solutions (Ag–Au hydrosols) by simply mixing disodium salt of ethylenediaminetetraacetic acid (Na2EDTA) with AgNO3 and HAuCl4 in aqueous alkaline medium at 80 °C. We found that Na2EDTA act not only as a reductant of metal ions and a potent stabilizer of metal nanoparticle size, but also as an effective agent for controlling the composition of the formed nanoparticles, owing to the high complexing affinity of Na2EDTA to silver ions. It was found that by controlling Na2EDTA concentration in the reaction mixture it is possible to control not only size and size distribution of a synthesized colloidal bimetallic Ag–Au nanoparticles, but bimetallic Ag–Au nanoparticles composition (Ag/Au ratio) as well.