2008 Volume 6 Pages 237-240
Metal coordination polymers, such as cobalt-coordinated polypyrrole (CoPPy), have attracted much attention, because they are promising alternatives to oxygen reduction electrocatalysts for fuel cell applications, owing to their high oxygen reduction activity as well as corrosion protection performance. In this catalyst, incorporated cobalt acts as the catalytic active site for the catalytic reaction. Thus, if we can increase the number of active cobalt sites, the catalytic activity should increase. We demonstrated the improvement of catalytic activity of CoPPy, i.e., increase of cobalt sites, by the nano-scale structure control using appropriate counter-ion doping. We found that the inter-chain distance of PPy with dodecylbenzensulfonic acid (DBS) was significantly increased, up to 4.8 Å, while inter-chain distance of PPy with chloride ion was 3.4 Å. Also, the amount of cobalt on CoPPy-DBS was five times larger than that of CoPPy-Cl. This result indicates that the amount of the cobalt sites increase and consequently the catalytic activity is enhanced when the inter-chain distance increased by counter-ion doping. [DOI: 10.1380/ejssnt.2008.237]