Hydrothermal synthesis of platinum-group-metal nanoparticles by using HEPES as a reductant and stabilizer.
Platinum-group-metal (Ru, Os, Rh, Ir, Pd and Pt) nanoparticles are synthesized in an aqueous buffer solution of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) (200 mM, pH 7.4) under hydrothermal conditions (180 degrees C). Monodispersed (monodispersity: 11-15%) metal nanoparticles were obtained with an average particle 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 stability of the as-obtained metal nanoparticles were affected by the HEPES concentration, pH of the HEPES buffer solution, and reaction temperature. HEPES with two tertiary amines (piperazine groups) and terminal hydroxyl groups can act as a reductant and stabilizer. The HEPES molecules can bind to the surface of metal nanoparticles to prevent 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.
Department of Chemistry and Open Laboratory of Chemical Biology of the Institute of Molecular, Technology for Drug Discovery and Synthesis, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
Man-Ho
MH
So
Chi-Ming
CM
Ho
Rong
R
Chen
Chi-Ming
CM
Che
D001274:Atmospheric Pressure; D002384:Catalysis; D006108:Graphite / Q000138:chemical synthesis / Q000737:chemistry; D006531:HEPES / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D019216:Metals, Heavy / Q000138:chemical synthesis / Q000737:chemistry; D010316:Particle Size; D010984:Platinum / Q000737:chemistry*; D019163:Reducing Agents / Q000737:chemistry; D012996:Solutions; D013499:Surface Properties; D013696:Temperature; D014867:Water
D019216:Metals, Heavy; D019163:Reducing Agents; D012996:Solutions; D014867:Water; D010984:Platinum; D006108:Graphite; D006531:HEPES