1. Field of the Invention
Aspects of the present invention relate to a sulfur-containing mesoporous carbon, a method of manufacturing the same, and a fuel cell using the sulfur-containing mesoporous carbon, and more particularly, to a sulfur-containing mesoporous carbon having a high affinity to noble metal catalyst particles, a method of manufacturing the same, a supported catalyst using the sulfur-containing mesoporous carbon as a catalyst support, and a fuel cell using the supported catalyst.
2. Description of the Related Art
A catalyst plays an important role in fuel cell technology as the catalyst is contained in electrodes for the fuel cells to facilitate the electrochemical reaction therein; thus, many attempts have been made to increase the activity of the catalyst. Since the activity of the catalyst increases as the reaction surface area of the catalyst increases, the diameter of catalyst particles should be reduced to increase the reaction surface area of the catalyst and the catalyst should be uniformly distributed in the electrodes. As such, a catalyst support should also have a large surface area, and thus, much research has been dedicated to increasing the surface area of the catalyst support.
In addition to a large surface area, which may be obtained through high porosity, a catalyst support for a fuel cell should be electrically conductive so as to act as a path for the flow of electrons. Also, the catalyst support should support the catalyst particles such that the catalyst particles are highly dispersed, and the catalyst support should have a connected pore structure that facilitates the transfer and transport of fuels. Examples of such a catalyst support include amorphous microporous carbon powder, such as activated carbon or carbon black, structure-ordered carbon molecular sieve materials and the like. For example, see Korean Patent Laid-open Publication No. 2001-0001127.
However, the micropores of such amorphous microporous carbon particles are poorly connected. Therefore, in a conventional direct methanol fuel cell (DMFC), a supported catalyst that is prepared using amorphous microporous carbon particles as a catalyst support exhibits a lower reactivity than unsupported catalyst in which a metal particle itself is used as a catalyst.
However, if the metal particle itself is used as a catalyst, a large amount of the catalyst is required; thus, the manufacturing costs of the DMFC increase. Accordingly, the development of a supported catalyst that can improve the reactivity of a catalyst is urgently required.
One of the crucial problems of electrodes for fuel cells is an agglomeration of catalyst particles when driving the fuel cells for a long period or operating at a high temperature. The agglomeration of catalyst particles increases the size of the catalyst particles, which reduces the number of active sites and hence, the activity of an electrode reaction.