(617ej) Connected Nanoparticle Catalysts Having a Porous, Hollow Capsule Structure As Carbon-Free Electrocatalysts for Polymer Electrolyte Fuel Cells

We developed connected
carbon-free platinum-iron (PtFe) nanoparticle catalysts
with porous hollow capsule structure (Fig. 1) as oxygen-reduction-reaction
(ORR) electrocatalysts for polymer electrolyte fuel
cells (PEFCs).^[1] This catalysts
consist of a beaded network by connected PtFe
nanoparticles with a crystallite size of 6~7 nm and a chemically-ordered (face centered
tetragonal) superlattice structure. The beaded
network is electrically conductive; thus, carbon-supports can be removed from
catalyst layers in PEFCs. We have demonstrated that an MEA prepared using a
carbon-free cathode of connected PtFe-nanoparticle
catalysts was highly durable against start-up/shut-down operations because of
the elimination of carbon-corrosion problems.Moreover, an ORR specific
activity of a connected PtFe catalyst is about 9 times
higher than that of a commercial Pt-nanoparticle
catalyst supported on carbon black (Pt/C). Recent
results will be explained.

[1] T. Tamaki, H. Kuroki, S. Ogura, T. Fuchigami, Y. Kitamoto, and T.
Yamaguchi, Energy Environ. Sci., 8,
3545-3549 (2015)

Fig. 1.
Schematic illustration and TEM images of a carbon-free connected PtFe-nanoparticle catalyst with porous hollow capsule
structure and its ORR activity compared with catalysts on carbon.