The slow rate of the oxygen reduction reaction
(ORR) is the main barrier limiting the commercialization of
proton exchange membrane fuel cells on an industrial scale. Here,
we report a one-step synthetic strategy of a class of carbonsupported
Pt−Co alloy concave nanocubes (NCs) with {hk0}
high-index facets with a high ORR activity. The concave degree of
the Pt−Co alloy is tunable through adjusting the amount of short
carbon-chain capping agentn-butylamine. In the growth process,
carbon black serves as a dispersant to avoid the nanoparticle
aggregation and thus favor the generation of concave NCs in
addition to the function as the support for Pt−Co nanoparticles.
The carbon-supported Pt−Co concave NCs with 22% Pt−Co by
weight deliver a specific activity of 2.34 mA cm−2 and mass activity of 0.26 A mg−1
Pt toward ORR, representing 6.5-fold and twofold
enhancement, respectively, relative to the state-of-the-art commercial Pt/C. After 5000 cycles of the accelerated durability test, the
mass activity of carbon-supported Pt−Co concave NCs is still higher than that of pristine commercial Pt/C.