A phase transfer identification of core-shell structures in Au-Ru nanoparticles

The difference between the transfer of citrate-stabilized Au and Ru nanoparticles from the aqueous phase to toluene was used to develop a simple experimental procedure that can positively identify the formation of bimetallic Au-Ru nanoparticles with the core-shell structure formed in the seed-mediated growth process. The procedure was independently verified by UV-vis spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS). The experimental results clearly showed that core-shell nanoparticles of Au-Ru were formed by the seed mediated growth method using Au nanoparticle seeds. The reverse order of using Ru nanoparticles as the seeds, on the contrary, could only produce a physical mixture of isolated nanoparticles of Ru and Au under the same experimental conditions.