Hitachi Maxell Develops New Highly-Active Catalyst for Higher Performance Fuel Cells; Achieves 4.8x More Oxygen-Reduction Current than Platinum

  	 

Tokyo, Japan, Apr 1, 2008 - (JCN Newswire) - Hitachi Maxell, Ltd.
has announced development of a new catalyst used for
oxygen-reduction reactions at the cathode of a polymer electrolyte fuel
cell (PEFC). The new catalyst is gold-platinum (AuPt) nano-particle 2 to
3 nm in size and can generate approximately 4.8 times the
oxygen-reduction current per unit area than commercial platinum
catalysts.

PEFCs are a promising clean-energy source for automobiles, homes, and
mobile devices. Platinum is commonly used as the catalyst for the
oxygen-reduction reaction in PEFCs, but platinum is an extremely
expensive precious metal, so reducing material cost for PEFCs by
minimizing the amount of platinum used, while improving its catalytic
effect is an important R&D topic.

Increasing the surface area of the catalyst by reducing particle size is
an effective way of improving catalytic activity. It has also been
reported that the addition of base metals such as iron, cobalt and
nickel to platinum also improves the oxygen-reduction reaction rate, but
these kinds of base metals dissolve easily in the acidic environment of
a PEFC where the catalyst is working, which is a problem.

Maxell has developed a new catalyst for oxygen-reduction reactions in
PEFCs. The new catalyst is a composition of platinum and gold and is
resistant to acidic environments. It was difficult to synthesize gold
particles smaller than 5 nm due to its relatively low melting point, but
by applying a proprietary nano-level particle synthesizing technology,
Maxell has succeeded in developing a high-activity structure in which
the gold and platinum are not fully alloyed for the new catalyst. Using
citric acid as a reducing agent, AuPt catalyst particles 2 to 3 nm in
size were synthesized at 373 K. Compared with platinum catalysts, this
new AuPt catalyst achieves approximately 4.8 times higher
oxygen-reduction current per unit area. X-ray diffraction analysis
revealed that the gold and platinum are not fully alloyed and it is
supposed that this structure results in the improved the
oxygen-reduction reaction activity.

This success represents a large step closer to fuel cells that are
practical for applications requiring large current, such as automobiles
and homes.

Maxell presented this new technology for synthesizing a highly-active
AuPt catalyst at the 101st catalysis conference held March 29 at the
Tower Hall Funabori in Tokyo.

Maxell will continue nano-technology research and development towards
practical applications in polymer-electrolyte and direct-methanol fuel
cells.

Hitachi Maxell

Since its foundation in 1960, Hitachi Maxell, Ltd. has led
the electronics industry at home and abroad in the fields of memory and
mobility. Maxell is a leading manufacturer of information storage media
products including magnetic tapes, optical disks, and battery products
including lithium ion rechargeable batteries, micro batteries and dry
cell batteries. For more information on Maxell, please visit the
Company's web site at www.maxell.com .