In Situ Generation of Two-Dimensional Au-Pt Core-Shell Nanoparticle Assemblies.

Two-dimensional assemblies of Au-Pt bimetallic nanoparticles are generated in situ on polyethyleneimmine (PEI) silane functionalized silicon and indium tin oxide (ITO) coated glass surfaces. Atomic force microscopy (AFM), UV-Visible spectroscopy, and electrochemical measurements reveal the formation of core-shell structure with Au as core and Pt as shell. The core-shell structure is further supported by comparing with the corresponding data of Au nanoparticle assemblies. Static contact angle measurements with water show an increase in hydrophilic character due to bimetallic nanoparticle generation on different surfaces. It is further observed that these Au-Pt core-shell bimetallic nanoparticle assemblies are catalytically active towards methanol electro-oxidation, which is the key reaction for direct methanol fuel cells (DMFCs).