Shape control of Pt nanoparticles

A preparative method to control the shape of platinum (Pt) nanoparticles in the presence of sodium polyacrylate (PAA) or poly(N-vinyl-2-pyrrolidone) ( PVP) is described. Regardless of the kind of protective polymer used, the d ominant shape of Pt nanoparticles was controlled by changing the reduction rate of Pt4+ ions. Tetrahedral particles predominated by using H-2 reductio n of H-2[PtCl6]. Methanol reduction generated mainly truncated octahedral p articles. It stems that the slow: H-2 reduction of pt(4+) ions favorably le ads to the Formation of tetrahedral Pt nuclei enclosed with Foul {111} plan es that have the lowest surface energy. The truncated octahedral nuclei are formed by the faster reduction with methanol. The selective growth of the {111} planes takes place at a lower polymer concentration anti results in t he generation of cubic nanoparticles.