The oxidation of carbon catalyst supports causes degradation in catalyst performance in proton exchange membrane fuel cells (PEMFCs). Indium tin oxide (ITO) is considered as a candidate for an alternative catalyst support. The electrochemical stability of ITO was studied by use of a rotating disk electrode (RDE). Oxidation cycles between +0.6 and +1.8 V were applied to ITO supporting a Pt catalyst. Cyclic voltammograms (CVs) both before and after the oxidation cycles were obtained for Pt on ITO, Hispec 4000 (a commercially available catalyst), and 40 wt.% Pt dispersed in-house on Vulcan XC-72R. Pt on ITO showed significantly better electrochemical stability, as determined by the relative change in electrochemically active surface area after cycling. Hydrogen desorption peaks in the CVs existed even after 100 cycles from 0.6 to 1.8 V for Pt on ITO. On the other hand, most of the active surface area was lost after 100 cycles of the Hispec 4000 catalyst. The 40 wt.% Pt on Vulcan made in-house also lost most of its active area after only 50 cycles. Pt on ITO was significantly more electrochemically stable than both Hispec 4000 and Pt on Vulcan XC-72R. In this study, it was found that the Pt on ITO had average crystallite sizes of 13 nm for Pt and 38 nm for ITO. Pt on ITO showed extremely high thermal stability, with only ∼1 wt.% loss of material for ITO versus ∼57 wt.% for Hispec 4000 on heating to 1000 °C. The TEM data show Pt clusters dispersed on small crystalline ITO particles. The SEM data show octahedral shaped ITO particles supporting Pt.
[1]
P. Serp,et al.
Carbon nanotubes and nanofibers in catalysis
,
2003
.
[2]
S. Srinivasan,et al.
Carbon supports for phosphoric acid fuel cell electrocatalysts: alternative materials and methods of evaluation
,
1981
.
[3]
P. Pickup,et al.
Electron and proton transport in gas diffusion electrodes containing electronically conductive proton-exchange polymers
,
1998
.
[4]
I. Nikolov,et al.
Corrosion resistance and catalytic activity of tungsten carbide in phosphoric acid
,
1984
.
[5]
P. Shen,et al.
The beneficial effect of the addition of tungsten carbides to Pt catalysts on the oxygen electroreduction.
,
2005,
Chemical communications.
[6]
Tsutomu Ioroi,et al.
Sub-stoichiometric titanium oxide-supported platinum electrocatalyst for polymer electrolyte fuel cells
,
2005
.
[7]
Z. Laušević,et al.
Boron and phosphorus doped glassy carbon: I. Surface properties
,
1997
.
[8]
Guoying Chen,et al.
DEVELOPMENT OF SUPPORTED BIFUNCTIONAL ELECTROCATALYSTS FOR UNITIZED REGENERATIVE FUEL CELLS
,
2002
.
[9]
Hardcover,et al.
Carbon: Electrochemical and Physicochemical Properties
,
1988
.
[10]
T. Jarvi,et al.
Electrocatalytic corrosion of carbon support in PEMFC cathodes
,
2004
.
[11]
P. Achard,et al.
Highly dispersed platinum on carbon aerogels as supported catalysts for PEM fuel cell-electrodes: comparison of two different synthesis paths
,
2004
.