Ag@Au and Au@Ag Core–Shell Nanoparticles: Insights on the Growth Process and Interactions with Small Molecules

In this investigation, we employed simulations and computational methodologies to examine pure silver and gold nanoparticles (NPs), alongside their core–shell configurations. Our research delved into, assessing the effects and adsorption tendencies of methanethiol molecules on diverse sites within these NPs. In our calculations, the effects of the inclusion of dispersion forces are analyzed. Structural analysis unveiled contractions in larger NPs and notable variations in adsorption energies across silver and gold surfaces. Furthermore, our study scrutinized not only the growth process but also the adsorption behavior of a model molecule within core–shell structures. We found that the arrangement of metal layers within these structures significantly impacted the adsorption energies of methanethiol, closely resembling the behavior observed in the smaller pure gold NPs. Notably, even a single shell layer led to discernible changes in the electronic structure. Overall, our investigation underscored the profound influence of the NP size, composition, and arrangement on adsorption energies. Interestingly, introducing methanethiol molecules to larger-scale NPs exhibited minimal impact on the electronic structure despite the evident changes in adsorption behaviors.