Synthesis of Single-Crystalline Platinum Nanorods within a Soft Crystalline Surfactant–PtII Complex

Single-crystalline platinum nanorods, monodisperse in diameter, are synthesized through a simple process at room temperature, in cetyltrimethyl ammonium bromide (CTAB) solution. The complexation of the CIA + surfactant ion with tetrachloroplatinate in the presence of hexanol leads to the formation of a precipitate with a lamellar crystalline structure. The reduction of Pt" metal ions to Pt 0 is carried out using y radiolysis. Transmission electron microscopy (TEM) observations of the nanoparticles extracted from the solution, three weeks after radiolysis, revealed single-crystalline Pt nanorods, monodisperse in diameter (3-4 nm) and 20-60 nm long. By following the shape of the nanorods at various stages of the growth, it was found that the single-crystalline nanorods grow by coalescence of spherical seeds 3-4 nm in diameter. This suggests an aggregative mechanism similar to that recently observed for silver particles in solution.