Electrocatalysis at Platinum and Bimetallic Alloys - Fuel Cell Catalysis: A Surface Science Approach - page 313

& CHAPTER 10
Electrocatalysis at Platinum
and Bimetallic Alloys
MASAHIRO WATANABE and HIROYUKI UCHIDA
Clean Energy Research Center, University of Yamanashi, Takeda 4, Kofu 400-8510, Japan
10.1 INTRODUCTION
Polymer electrolyte fuel cells (PEFCs) have attracted great interest as a primary power
source for electric vehicles or residential co-generation systems. However, both the
anode and cathode of PEFCs usually require platinum or its alloys as the catalyst,
which have high activity at low operating temperatures (,100 8C). For large-scale
commercialization, it is very important to reduce the amount of Pt used in fuel cells
for reasons of cost and limited supply.
In order to obtain high mass activity of Pt, it is essential to disperse Pt or alloy
nanoparticles on high surface area supports. Some questions then arise. What kind
of alloys and composition should we choose? Is there any good parameter for screen-
ing the catalysts? What size of catalyst particles should we prepare to obtain the
maximum performance? Unfortunately, there has been much controversy about
such issues in the literature.
In order to establish a clear strategy, we have examined the properties of Pt-based
catalysts for both the hydrogen oxidation reaction (HOR) and the oxygen reduction
reaction (ORR) systematically and comprehensively using various techniques, the
results of which complement each other. We have also developed a standard
method to evaluate the real activity. In this chapter, we summarize our recent research
results.