A polymer electrolyte fuel cell (PEFC) can operate in a low-temperature region and has high energy conversion efficiency, and a time period required for its startup is short. In addition, the system of the PEFC can be made small and lightweight. Accordingly, the PEFC has been expected to find applications in power sources for electric vehicles, portable power sources, and household co-generation systems.
However, large amounts of platinum catalysts are used in the PEFC. The use of the platinum catalysts causes an increase in cost, which is one factor that may inhibit the widespread use of the PEFC. In addition, a concern has been raised in that restriction is imposed on the PEFC in terms of platinum reserves.
In view of the foregoing, the development of a novel catalyst that can replace the platinum catalyst has been advanced. That is, for example, a carbon catalyst obtained by imparting a catalytic activity to a carbon material itself has been proposed (see, for example, JP 2007-026746 A, JP 2007-207662 A and JP 2008-282725 A).