Au/Ag alloy nanoparticles (NPs) were successfully prepared by a one step synthesis using HAuCl4 and [Ag(NH3)2]+ as the corresponding precursors in a microwave-induced plasma in liquid process (MWPLP) without the addition of any organic protecting or reducing agents. The time dependent reduction and particle formation during the 140 min plasma discharge were studied with TEM, UV-vis extinction spectra, and ICP-OES. After 140 min, the HAADF-STEM and EDX results indicated that the obtained Au/Ag NPs were alloy NPs. Varying the input molar ratios of the metal precursors allowed for control of the composition of the Au/Ag alloy NPs.
