Electrohydrodynamic Assembly of Ambient Ion-Derived Nanoparticles to Nanosheets at Liquid Surfaces

We describe an ambient ion-based method to create free-standing metal nanosheets, which in turn are composed of nanoparticles of the corresponding metal. These nanoparticle-nanosheets (NP-NSs) were formed by the electrospray deposition (ESD) of metal ions on a liquid–air interface leading to nanoparticles that self-organize under the influence of electrohydrodynamic flows, driven by the electric field induced by the applied potential. Such a two-dimensional organization of noble metals is similar to the assembly of molecules at liquid–air interface and has the possibility of creating a category of new materials useful for diverse applications. Enhanced catalytic activity of the formed NP-NSs for Suzuki–Miyaura coupling reaction was demonstrated, which was attributed to their large surface-to-volume ratios.