Tuning Complex Shapes in Platinum Nanoparticles: From Cubic Dendrites to Fivefold Stars

摘要

The synthesis of nanoparticles (NPs) exhibiting large surface-area-to-volume ratios has been a long-sought goal in developing various applications such as ultrasensitive sensors'11 or highly active catalysts. In addition to a large specific area, crystallographic planes exposed on the surface of the NPs are key parameters for the reactivity and selectivity of NPs in catalytic processes. Thus, intense research has been devoted to the shape control of noble-metal nanocrystals. For example, for Pt-based nanoparticles, dendritic nanostruc-tures, branched-NPs, or multipods exhibit enhanced catalytic activities relative to their spherical counterparts Such shape control could be obtained by manipulating the reduction kinetics through temperature, pH, ligands, or the addition of small amounts of nucleating agents. Interestingly, in this variety of shapes, only few groups reported multiply twinned Pt nanoparticles, whereas decahedrons are fairly common for most of the noble metals (e.g. Au, Ag, Rh). However, these twinned NPs could offer significant benefits toward catalysis because they have mainly their {111} faces exposed.