The preparation of monodisperse colloidal metal particles from microemulsions

Abstract Monodispere particles (in the size range 3–5 nm) at Pt, Pd, Rh and Ir have been prepared by reduction of metal salts which are dissolved in the water pools of microemulsions with hydrogen or hydrazine. The standard deviation and reproducibility of the diameter is ± 10SS. Two microemulsion systems were tested: water/cetyltrimethylammonium bromide/octanol and water/pentaethyleneglycol dodecyl ether/hexane (or hexadecane). The method to probably Generally applicable provided the following conditions are met: (1) the solubility of the salts should not be limited by specific interactions with the solvent or the surfactant, (2) the reducing agent should react only with, the salt and (3) the temperature can be adjusted so that the kinetics of the reduction are not very slow. Under properly chosen conditions the particles can be transferred to supports without agglomeration.