posted on 2016-12-28, 16:20authored byAlaina
L. Strickler, Ariel Jackson, Thomas F. Jaramillo
Electrochemical oxygen reduction
is an important reaction for many
sustainable energy technologies, such as fuel cells and metal–air
batteries. Kinetic limitations of this reaction, expensive electrocatalysts,
and catalyst instability, however, limit the commercial viability
of such devices. Herein, we report an active Ir@Pt core–shell
catalyst that combines platinum overlayers with nanostructure effects
to tune the oxygen binding to the Pt surface, thereby achieving enhanced
activity and stability for the oxygen reduction reaction. Ir@Pt nanoparticles
with several shell thicknesses were synthesized in a scalable, inexpensive,
one-pot polyol method. Electrochemical analysis demonstrates the activity
and stability of the Ir@Pt catalyst, with specific and mass activities
increasing to 2.6 and 1.8 times that of commercial Pt/C (TKK), respectively,
after 10 000 stability cycles. Activity enhancement of the
Ir@Pt catalyst is attributed to weakening of the oxygen binding to
the Pt surface induced by the Ir core.