FTIR study of the adsorption of the capping material to different platinum nanoparticle shapes

FTIR spectroscopy has been used to study the binding geometry of polyacrylate capping material on cubic and tetrahedral platinum nanoparticles. It is proposed that the capping material forms an ester-like linkage to the Pt surface on the tetrahedral shapes through the hydroxyl oxygen atom of the carboxylic acid moiety of the polyacrylate (linear adsorption configuration). On the cubic particle the adsorption is through both of the carboxylic oxygen atoms (bridge adsorption configuration). These shaped nanoparticles are synthesized by changing the starting ratio of the capping material to that of the Pt salt. The results are discussed in terms of the effect of changing the concentration of the polyacrylate capping material on the mode of bonding to the surface. This might be a factor in determining the final shape formed.