W Tungsten

Platinum-group-metal (Ru, Os, Rh, Ir, Pd and Pt) nanoparticles are synthesized in an aqueous buffer colloidal suspension of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) (200 mM, pH 7.4) care of hydrothermal conditions (180 °C). Monodispersed (monodispersity: 11-15 %) metal nanoparticles were obtained with an usual mite size of less than 5 nm (Ru: 1.8±0.2, Os: 1.6±0.2, Rh: 4.5±0.5, Ir: 2.0±0.3, Pd: 3.8±0.4, Pt: 1.9±0.2 nm). The size, monodispersity, and determination of the as-obtained metal nanoparticles were mannered by the HEPES concentration, pH of the HEPES buffer solution, and repulsion temperature. HEPES with two tertiary amines (piperazine groups) and terminating hydroxyl groups can act as a reductant and stabilizer. The HEPES molecules can fasten to the surface of metal nanoparticles to mitigate metal nanoparticles from aggregation. These platinum-group-metal nanoparticles could be deposited onto the surface of graphite, which catalyzed the aerobic oxidation of alcohols to aldehydes <<>>