CuO-nanoparticle-induced controlled synthesis of various Pt nanostructures and their shape-dependent catalytic properties in oxidisation of methanol

This Letter reports on the synthesis of platinum (Pt) nanoparticles with controlled shape and size in oleylamine through using CuO nanoparticles as a template. By adjusting the reaction temperature and the amount of Pt precursor, monodispersed octahedron, highly branched nanosphere, concaved Pt nanocube and nanorod were prepared. Transmission electron microscopy, high-resolution transmission electron microscopy and energy dispersive X-ray spectroscopy were used to investigate the formation mechanism. The overgrowth rate is believed to play an important role in the evolution of nanoparticles´ shape. A reaction temperature higher than 185°C and Cu/Pt molar ratio (<;0.1) can accelerate the overgrowth rate. The fast growth rate along <;111>; direction leads to the formation of multi-branched and concaved nanocubes. The reaction condition (Cu/Pt = 0.1; 185°C) prefers the formation of monodispersed octahedron Pt nanoparticles. The absence of CuO facilitates the formation of a branched nanosphere. The electro-catalytic oxidisation of methanol shows that the catalytic ability has significant shape-dependence. Compared with other shaped nanoparticles, concaved cube nanoparticles have excellent catalytic performance because they are coated by high index facets.