Synthesis of Ru Icosahedral Nanocages with a Face-Centered-Cubic Structure and Evaluation of Their Catalytic Properties

Owing to the presence of {111} facets, twin boundaries, and strain fields on the surface, noble-metal nanocrystals with an icosahedral shape have been reported with stellar performance toward an array of catalytic reactions. Here, we report the successful synthesis of Ru icosahedral nanocages with a face-centered cubic (fcc) structure by conformally coating Pd icosahedral seeds with ultrathin Ru shells, followed by selective removal of the Pd cores via chemical etching. We discovered that the presence of bromide ions was critical to the layer-by-layer deposition of Ru atoms. According to in situ XRD, the fcc structure in the Ru nanocages could be retained up to 300 °C before it was transformed into the conventional hexagonal close-packed (hcp) structure. Additionally, the icosahedral shape of the Ru nanocages could be largely preserved up to 300 °C. The Ru icosahedral nanocages with twin boundaries on the surface exhibited greatly enhanced activities toward both the reduction of 4-nitrophenol and decompos...