Ordered Intermetallics as Electrocatalysts for Fuel Cell Applications Héctor D. Abruña , Francis J. DiSalvo Dept. of Chemistry and Chemical Biology Baker Laboratory, Cornell University Ithaca, New York 14853-1301 Pt PtBi 2.4 mA/cm 2 0.063 mA/cm 2 xpanded Pt (111) plane Pt-Pt 2.77 Å PtBi (001) plane Pt-Pt 4.32 Å
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Ordered Intermetallics as Electrocatalysts for Fuel Cell ...Ordered Intermetallics as Electrocatalysts for Fuel Cell Applications Héctor D. Abruña, Francis J. DiSalvo Dept. of Chemistry
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Ordered Intermetallics as Electrocatalysts for Fuel Cell
Applications
Héctor D. Abruña, Francis J. DiSalvo Dept. of Chemistry and Chemical Biology
Baker Laboratory, Cornell University Ithaca, New York 14853-1301
Pt PtBi 2.4 mA/cm2
0.063 mA/cm2
xpanded
Pt
(111) plane Pt-Pt 2.77 Å
PtBi
(001) plane Pt-Pt 4.32 Å
Alloys vs. Ordered Intermetallics
(A)
Alloy; e.g. Pt/Ru (1:1)
(B)
Ordered Intermetallic e.g. BiPt
Bismuth Platinum (BiPt) Intermetallic Phase
¾ Powder Refinement for BiPt
---- Residual between experimental
P63/mmc
a =
c = 5.490 Å
Pt Bi
Diffraction X-ray
4.315 Å
and theoretical results
Platinum vs. PtBi
Pt (111) plane
Pt-Pt 2.77 Å
PtBi
(001) planePt-Pt 4.32 Å
Voltammetric Profile in H2SO4
¾ Cyclic Voltammetry in 0.1 M H2SO4 at a sweep rate of 10 mV/s
Pt
5 µA
PtBi
20 µA
E(V) vs. Ag/AgCl
8
Enhanced Catalytic Activity for Formic Acid Oxidation
¾ Cyclic Voltammetry in 0.1 M H2SO4 + 0.125 M formic acid solution at a sweep rate of 10 mV/s
Pt 0.063 mA/cm2
Expanded
PtBi 2.4 mA/cm2
E(V) vs. Ag/AgCl
8
Onset Potential (obtained at 10 mA/cm2 )as a function of the Formic Acid concentration.
Rotating Disk Electrode Characterization
CO Tolerance
before after
10 µA
0.1M H2SO4
BiPt
-0.2 0.0 0.2 0.4 0.6 0.8 1.0
E vs Ag/AgCl
Cyclic voltammograms at 50 mV/sec for a BiPt electrode in 0.1M H2SO4 before and after exposure to CO
CO Adsorption on a polycrystalline Pt surface
0.1 mAPt
-0.2 0.0 0.2 0.4 0.6 0.8 1.0 E vs Ag/AgCl
DEMS for BiPt in 0.125 M HCOOH,
0.1 M H2SO4
FT-IR Studies of CO2 and CO
formation at BiPtand Pt electrodes
during formic acid oxidation.
Conclusions: We have studied the electrocatalytic activity of the ordered intermetallic BiPt toward formic acid oxidation. exhibits enhanced electrocatalytic activity when compared to polycrystalline platinum. voltammetry, rotating disk voltammetry (RDE), (differential electrochemical mass spectrometry) we have characterized the current density, onset potentials, kinetics of oxidation, reaction intermediates, and product distribution.