Enhanced Oxygen Reduction
Reaction Activity and Characterization
of Pt–Pd/C Bimetallic Fuel Cell Catalysts with Pt-Enriched
Surfaces in Acid Media
Licheng Liu
Gabor Samjeske
Shin-ichi Nagamatsu
Oki Sekizawa
Kensaku Nagasawa
Shinobu Takao
Yoshiaki Imaizumi
Takashi Yamamoto
Tomoya Uruga
Yasuhiro Iwasawa
10.1021/jp308021a.s001
https://acs.figshare.com/articles/journal_contribution/Enhanced_Oxygen_Reduction_Reaction_Activity_and_Characterization_of_Pt_Pd_C_Bimetallic_Fuel_Cell_Catalysts_with_Pt_Enriched_Surfaces_in_Acid_Media/2470717
Three types of bimetallic Pt–Pd nanoparticles
with different
core–shell structures besides Pt and Pd nanoparticles were
synthesized by coreduction and sequential reduction methods in ethylene
glycol. The synthesized nanoparticles were supported on carbon to
prepare five different electrocatalysts Pt/C, Pd/C, PdPt alloy/C,
Pd(core)–Pt(shell)/C, and Pt(core)–Pd(shell)/C for oxygen
reduction reaction (ORR) in fuel cells. The nanoparticles and supported
catalysts were characterized by means of transmission electron microscopy
(TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray powder
diffraction (XRD), extended X-ray absorption fine structure (EXAFS),
and cyclic voltammetry (CV). It was proposed by these characterizations
that the PdPt alloy/C, Pd(core)–Pt(shell)/C, and Pt(core)–Pd(shell)/C
catalysts constituted Pd<sub>4</sub>Pt<sub>1</sub>(core)–Pt(two-layers
shell), Pd (core)–Pd<sub>2</sub>Pt<sub>1</sub>(three-layers)–Pt(three-layers
shell), and Pt(core)–Pt<sub>2</sub>Pd<sub>1</sub>(two-layers)–Pd
(microcrystal shell), respectively. The Pt surface-enriched catalysts
were more stable than the Pd surface-enriched catalysts in long-term
CV scanning in acid electrolyte. The Pt/C, PdPt alloy/C, and Pd(core)–Pt(shell)/C
catalysts with Pt-enriched surfaces showed much higher ORR specific
activity than the Pd/C and Pt(core)–Pd(shell)/C catalysts with
Pd-enriched surfaces. The Pt surface-enriched bimetal catalysts with
core–shell structures showed the higher Pt-based mass activity
than the Pt monometal catalyst. The PdPt catalysts with Pd/Pt = 2
and 4 in an atomic ratio were also prepared by the coreduction method.
The Pt-enriched surfaces formed also with these samples, but the ORR
specific activity and (Pd + Pt)-based mass activity decreased with
increasing Pd/Pt ratios (1, 2, and 4). The present study provided
core–shell catalysts with better ORR activity, which may be
useful for understanding key issues to develop next-generation fuel-cell
cathode catalysts.
2012-11-08 00:00:00
EXAFS
Pt monometal catalyst
fuel cells
cyclic voltammetry
CV scanning
PdPt catalysts
ethylene glycol
XRD
oxygen reduction reaction
acid electrolyte
Acid MediaThree types
Pd nanoparticles
TEM
Enhanced Oxygen Reduction Reaction Activity
transmission electron microscopy
ORR activity
sequential reduction methods
coreduction method