(80e) Compressively-Strained and Interconnected Platinum Cones with Greatly Enhancedactivity and Durability Toward Oxygen Reduction

We report a facile synthesis of cone-shaped Pt nanoparticles featuring compressively-strained
{111} facets by depositing Pt atoms on the vertices of Pd nanocrystals, followed by
selective removal of the Pd template via wet etching. By controlling their dimensions down to ca.
2 nm, the Pt cones show greatly enhanced specific and mass activities toward oxygen reduction,
with values being four and 10 times as high as those of commercial Pt/C. Both the strain field and
the observed activity trend are rationalized using density functional theory calculations. With the
formation of ultrathin linkers among the Pt cones derived from the same Pd seed, the
interconnected Pt cones acquire stronger interactions with the carbon support, preventing them
from detachment and aggregation during the catalytic reaction. Even after 20,000 cycles of
accelerated durability test, the Pt cones still show a mass activity of 8.4 times as high as the initial
value of the Pt/C.