title: Facile synthesis of iridium nanocrystals with well-controlled facets using seed-mediated growth.
abstract: Iridium nanoparticles have only been reported with roughly spherical shapes and sizes of 1-5 nm, making it impossible to investigate their facet-dependent catalytic properties. Here we report for the first time a simple method based on seed-mediated growth for the facile synthesis of Ir nanocrystals with well-controlled facets. The essence of this approach is to coat an ultrathin conformal shell of Ir on a Pd seed with a well-defined shape at a relatively high temperature to ensure fast surface diffusion. In this way, the facets on the initial Pd seed are faithfully replicated in the resultant Pd@Ir core-shell nanocrystal. With 6 nm Pd cubes and octahedra encased by {100} and {111} facets, respectively, as the seeds, we have successfully generated Pd@Ir cubes and octahedra covered by Ir{100} and Ir{111} facets. The Pd@Ir cubes showed higher H2 selectivity (31.8% vs 8.9%) toward the decomposition of hydrazine compared with Pd@Ir octahedra with roughly the same size.
authors: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , Atlanta, Georgia 30332, United States.
authors: Xiaohu
authors: X
authors: Xia
authors: Legna
authors: L
authors: Figueroa-Cosme
authors: Jing
authors: J
authors: Tao
authors: Hsin-Chieh
authors: HC
authors: Peng
authors: Guangda
authors: G
authors: Niu
authors: Yimei
authors: Y
authors: Zhu
authors: Younan
authors: Y
authors: Xia
mesh_terms: D001205:Ascorbic Acid / Q000737:chemistry; D019855:Ethylene Glycol / Q000737:chemistry; D007495:Iridium / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry
chemical_list: D007495:Iridium; D010165:Palladium; D019855:Ethylene Glycol; D001205:Ascorbic Acid