title: Polyol syntheses of palladium decahedra and icosahedra as pure samples by maneuvering the reaction kinetics with additives.
abstract: This article reports a robust method based upon polyol reduction for the deterministic synthesis of Pd decahedra or icosahedra with tunable sizes and a purity approaching 100%. The success of such a selective synthesis relies on an ability to fine-tune the reaction kinetics through the addition of Na2SO4 and HCl for decahedra and icosahedra, respectively. In the absence of any additive, the product of a similar synthesis in diethylene glycol contained 10% decahedra and 90% icosahedra. By optimizing the amount of Na2SO4 (or HCl) added into the reaction solution, the percent of decahedra (or icosahedra) in the product could be increased up to 100%. The roles of Na2SO4 and HCl were also investigated in great detail, and two plausible mechanisms were proposed and validated through a set of experiments. In general, a faster reduction rate is needed for the synthesis of Pd decahedra when compared with what is needed for Pd icosahedra. This work not only offers a simple approach to the deterministic syntheses of Pd decahedra and icosahedra but also provides an in-depth understanding of the mechanisms involved in shape-controlled syntheses of noble-metal nanocrystals from the perspective of reaction kinetics. On the basis of the mechanistic understanding, we have also achieved successful synthesis of Pd decahedra as pure samples by adding a proper amount of NaOH into the system to speed up the reduction kinetics.
authors.forename: Hongwen
authors.initials: H
authors.lastname: Huang
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Aleksey
authors.initials: A
authors.lastname: Ruditskiy
authors.forename: Hsin-Chieh
authors.initials: HC
authors.lastname: Peng
authors.forename: Xin
authors.initials: X
authors.lastname: Zhao
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Jingyue
authors.initials: J
authors.lastname: Liu
authors.forename: Zhizhen
authors.initials: Z
authors.lastname: Ye
authors.forename: Younan
authors.initials: Y
authors.lastname: Xia