No. 387: Successful adherence of platinum to carbon nanowall (December 22, 2011)

A research team lead by Prof. MasaruTachibana of Yokohama City University developed a technology to make platinum attached to a carbon nanowall (CNW). Platinum is used for the catalyst of a fuel cell, and the research team successfully the same degree of catalytic activity with platinum that they get with carbon black (CB) that is generally used for electrodes. The new technology can be applied to the development of an electrode that has more than 1,000 times higher conductivity than CB.

The research team used the solution reduction method to mix a CNW with platinum solution and make platinum attached to the CNW. The team members made the CNW apart by layer for uniform attachment, and applied platinum with a particle size of 3.6 nanometers on average to 18% in weight ratio. The effective activity area of one gram of platinum is about 70 square meters, which is the same level of CB. Because the CNW gets platinum on it while maintaining the structure of graphite, it is supposed to have catalytic activity, conductivity, and chemical stability, all of which are characteristics specific to graphite. A high degree of catalytic activity and conductivity are vital to increase the energy efficiency of a fuel cell. CB has a big specific surface area and a large amount of catalyst can be attached to it, but it is low in conductivity and chemical stability. On the other hand, graphite has a high degree of conductivity, but a low degree of adherability of catalyst. A carbon nanowall is a carbon nanomaterial composed of small graphite crystals.