Enhanced activity for oxygen reduction reaction on "Pt3Co" nanoparticles: direct evidence of percolated and sandwich-segregation structures.
Atomically resolved structures and compositions of Pt alloy nanoparticles were obtained using aberration-corrected high-angle dark field imaging, which was correlated to specific ORR activity based on a Pt surface area. The enhanced specific ORR activity (approximately 2 times relative to Pt) of acid-treated "Pt3Co" nanoparticles can be related to composition variations at the atomic scale and the formation of percolated Pt-rich and Pt-poor regions within individual particles. Upon annealing, we show direct evidence of surface Pt sandwich-segregation structures, which correspond to a specific ORR activity approximately 4 times relative to Pt.
Chen
Shuo
S
Electrochemical Energy Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Ferreira
Paulo J
PJ
Sheng
Wenchao
W
Yabuuchi
Naoaki
N
Allard
Lawrence F
LF
Shao-Horn
Yang
Y