Size sorting of Au and Pt nanoparticles from arbitrary particle size distributions

A K2BSPP (dipotassium bis(p-sulfonatophenyl)phenylphosphane dihydrate)-based method to sort and size refine Au and Pt nanoparticles has been developed. It makes use of K2BSPP to impart graduated stability to the nanoparticles in a number of NaCl solutions. The method offers a systematic approach to preparing metal nanoparticles of small diameters and a narrow size distribution from an arbitrary particle size distribution. TEM investigations confirmed the size refinement efficacy of this treatment method: in a typical experiment, the mean particle size and relative standard deviation of Au nanoparticles after three successive treatments were 5.18 and 0.055 nm, respectively, down from the corresponding values of 8.22 and 0.26 nm from the initial untreated nanoparticle solution. The K2BSPP-based size refinement procedure is a simple alternative to more complex chemical procedures and stringent process control that are currently required for the preparation of mono-dispersed systems.