An improved Brust’s procedure for preparing alkylamine stabilized Pt, Ru nanoparticles

An improved method to prepare alkylamine-stabilized Pt and Ru nanoparticles based on the original Brust’s procedure [J. Chem. Soc., Chem. Commun. (1994) 801] has been developed. The new method involves, firstly, mixing an aqueous solution of metal salts such as PtCl62−, PtCl42− or Ru3+ with an ethanol solution of dodecylamine; extracting the metal ions into a toluene layer; and finally reducing the metal ions to their zero valent states using NaBH4. Alkylamine-stabilized Pt nanoparticles prepared this way had a polyhedral or wormlike appearance, depending closely on the chemical nature of the metal precursor salts being used. On the contrary, dodecylamine-stabilized ruthenium nanoparticles were predominantly spherical. The particle formation and growth processes in the hydrocarbon layer could be influenced by the different ways dodecylamine was bound to H2PtCl6, K2PtCl4 or RuCl3 at the precursor stage.