Noble metal ions were reduced to form metallic nano-particles in diisooctyl sodium sulfosuccinate (AOT) by a sonochemical method. AOT has been known to form reverse micelle in organic solvent. Reduction rate of Pt(II) in AOT / dodecane solution was very slow with rate of 1.5 μM min^<-1> compared with those (ca. 20 μM min^<-l>) in aqueous solution of usual surfactants, such as polyethylene glycol monostearate (PEG-MS; noniomc), sodium dodecylbenzensulfonate (DBS; anionic) and sodium dodecylsulfate (SDS; anionic). In Pd(II) reduction, similar tendency to Pt(II) reduction was observed. A colloidal dispersion of Pt nano-particles in AOT / dodecane was stable for several months. The size of Pt particles (about 1 nm) prepared in this system was smaller than in SDS (3 nm). Au(III) ions with AOT in dodecane were reduced faster than Pt(II) and Pd(II), but formed particles (about 80 nm) were unstable to aggregate and precipitated in several hours. The results obtained in this work suggest that the reduction site of noble metal ions in AOT / dodecane is different from that in usual aqueous surfactants.
