Hitachi Maxell develops catalyst for higher performance fuel cells; Metals and catalysts

Hitachi Maxell Ltd of Japan has developed a catalyst that is used in oxygen reduction reaction at the cathode of polymer electrolyte fuel cells (PEFCs). PEFC is a potential source of clean energy for automobiles, homes and electronic devices.

At present, platinum (Pt) is generally used as a catalyst for oxygen reduction reaction in PEFCs. However, Pt is expensive, being a precious metal. Thus, an important theme for research and development (R&D) in this area has been in reducing material costs by minimizing the amount of Pt used, while creating improvements in the catalytic activity of Pt.

To this end, Hitachi Maxell says it has developed a catalyst that uses nanoscale amounts of gold (Au) and Pt. By applying nano-level particle synthetic technology, the company has succeeded in developing a catalyst with a high-activity structure in which Au and Pt are not fully alloyed. Using citric acid as a reducing agent, the Au/Pt catalyst, 2-3 nm in size, was synthesized at 373 K.

Compared with Pt catalysts, the Au/Pt version is said to achieve approximately 4.8 times higher oxygen reduction current per unit area.The company used X-ray diffraction analysis to observe the new catalyst material, and believe that the structure in which Au and Pt are not fully alloyed can significantly improve the oxygen reduction reaction activity.

This represents a large step closer to the practical use of fuel cells for applications requiring large current, such as power sources for automobiles and homes. The company will continue R&D based on thenanotechnology with a view to practical applications in direct methanol fuels cells, as well as polymer electrolyte fuel cells.

For further information, contact: Hitachi Maxell Ltd, 2-18-2 Iidabashi, Tokyo, Chiyoda-ku 102 8521, Japan; tel: 3351-58211; Internet: www.maxell.com