Shape-Controlled Syntheses Of Pt And Pt-based Alloy Nanoparticles

The study of the relationship between the structure and properties of noble metal nano catalyst is very important for designing and directing the synthesis of noble metal nanomaterials. Considerable attention has been paid to metal nanoparticles owing to their potential applications in many fields such as catalysis, optics, magnetic, optical sensing, biological labeling and among others. As important catalysts, in order to improve the catalytic performance, the preparation of monodispersive Pt and Pt-based alloy nanoparticles with high surface energy has been prepared, and the control of their sizes, morphologies and structures were also investigated. Up to now, Pt and Pt-based alloy nanoparticles with various morphologies have been obtained such as Pt concave cubes, Pt nanowires, Pt-Pd alloy hypercubes, octahedral and octapadal Pt-Au nanocrystal, Pt-Ru alloy cubic frame, and so on. In this paper, the shape-controlled syntheses of Pt and Pt-based alloy nanocrystals by means of microwave irradiation or hydrothermal approach. The electrocatalytic activities of the asprepared nanoparticles t were investigated.Pt nano-pompons were successfully synthesized with K2PtCl6 as a precursor, ascorbic acid as a reducing agent, CTAB as a stabilizer and water as a solvent by means of hydrothermal method. The as-prepared Pt nanopartcles were characterized by transmission electron microscopy(TEM), X-ray diffraction(XRD) and X-ray photoelectron spectrometry(XPS). The results demonstrated that the use of Br- ions was crucial to the formation of Pt nano-pompons. The reducing rate of Pt(4) ions was decreased due to the coordination of Brions with Pt(4) ions. The as-prepared Pt nano-pompons exhibited higher electrocatalytic activity than commercial Pt black in the electro-oxidation of methanol.Pt nanoflowers were successfully synthesized with H2PtCl6 as a precursor, tetraethylene glycol(TEG) as both a reducing agent and a solvent, polyvinylpyrrolidone(PVP) as a stabilizer in the presence of an appropriate amount of KI and octadecylamine under microwave irradiation. The as-prepared Pt nanopartcles were characterized by TEM, XRD and XPS. The results demonstrated that the use of I? ions was crucial to the formation of Pt nanoflowers. The as-prepared Pt nanoflowers exhibited higher electrocatalytic activity than commercial Pt black in the electro-oxidations of methanol.concave cubes Pt-Cu alloy nanocrystals were prepared in an extremely short time in tetra Pt-Cu alloy concave cubic nanocrystals were prepared in an extremely short time with H2PtCl6·6H2O and CuCl2·2H2O as precursors, as both a reducing agent and a solvent, PVP as a stabilizer in the presence of an appropriate amount of KI under microwave irradiation. The as-prepared Pt-Cu alloy concave cubic nanocrystals were characterized by TEM, SEM, XRD, high-angle annular dark-field scanning TEM(HAADF-STEM) and XPS. The results demonstrated that the use of I? ions was crucial to the formation of Pt-Cu alloy concave cubic nanocrystals. The as-prepared Pt-Cu alloy nanocrystals exhibited higher electrocatalytic activity than commercial Pt black in the electro-oxidations of formic acid and methanol.