Cheaper cathodes for fuel cells

Polymer electrolyte fuel cells−a promising technology for zero-emissions vehicles−could become less expensive to make, thanks to a new nanocomposite catalyst developed by Los Alamos National Laboratory researchers (Nature 2006, 443, 63). To reduce oxygen and oxidize hydrogen or methanol fuel, electrodes in these fuel cells contain precious-metal catalysts, such as platinum. As a low-cost alternative for the fuel cell's cathode, Piotr Zelenay and Rajesh Bashyam have developed a cobalt-polypyrrole composite (presumed structure shown). They chose polypyrrole to mimic pyrolyzed metal porphyrins, a class of non-precious-metal cathode catalysts that exhibit promising performance but suffer from poor stability. The cobalt-polypyrrole catalyst is stable, showing no appreciable decline in performance during 100 hours of operation. Zelenay notes this is "the first time that a non-precious-metal cathode catalyst, at low loading, has shown both a promising activity and stability at the same time."