Full range tuning of the composition of Au/Ag binary nanoparticles by spark discharge generation

Gold/silver bimetallic nanoparticles still attract extensive interest due to their favorable properties e.g. in plasmonics or catalysis. We present here a facile and robust way for the production of clean Au/Ag binary nanoparticles (BNPs) with a total control over the composition via the spark discharge nanoparticle generation technique. With the application of pure Ag and Au electrodes, a tuning range of 55 to 90% Au content was achieved, but this can be further extended to the full 0 to 100% range by using a couple of alloyed electrodes. An added benefit of the approach is that either the concentration or the mean particle size can be kept constant at every composition by adjusting the generator parameters. Based on the systematic experimental data collected, a semi-empirical model for the prediction of the Au/Ag BNP composition was also developed. This model was used to calculate the theoretically achievable Au/Ag composition at a given spark parameter set in the parameter range most commonly used in the literature.

Computer Simulation of the Formation Process of Cu-Au Nanoparticles by Condensation

The computer simulation method was used to examine condensation of 90124 Cu and Au atoms from the gas phase. To analyze the synthesis processes, there were selected chemical compositions Cu3Au, Cu-Au, Cu90Au10 and Cu60Au40 being cooled with liquid nitrogen during the condensation. The undertaken simulation showed that the increase in the percentage of gold atoms in the initial couple decreases the number of clusters of a relatively large size. Moreover, the analysis of the external view and the structure of Cu-Au nanoparticles of various chemical composition allowed us to conclude that a large number of binary nanoparticles were of an icosahedral structure.