Fuel cells have been studied for commercialization. Nevertheless there are still many problems left to solve. Among them more efficient electro-catalysts are desired in order to raise the cell voltage. If pure hydrogen is fed as fuel, there are no poisoning problems on the anode catalyst. However, when the alcoholic fuels such as methanol or ethanol are fed to the anode, the catalysts will be poisoned seriously by the intermediate products. Reduction of oxygen at the cathode is a little too slow even though on the best catalyst, i.e., Pt. New and more efficient catalysts to replace Pt should be developed to expand the fuel cell world. Recent development of catalysts for the fuel cells are cleared in this manuscript.

Polymer electrolyte-type fuel cells (PEFCs) that can operate in the medium temperature range with little humidification are strongly desired. Proton conductors based on inorganic amorphous materials, which are key materials to realize those PEFCs, have been widely investigated. We have developed a series of inorganic-organic hybrid and composite electrolyte materials derived from a sol-gel technique. In the present paper, preparation and characterization of our proton conducting materials and their application to fuel cells used under medium temperatures were reviewed.

Direct Methanol Fuel Cell (DMFC), which is worked by liquid energy source with high energy density like methanol solution, has been developing as the next-generation energy source for various mobile devices. However to be practical application, DMFC has several major problems arising from composing materials such as methanol cross over (MCO) and low efficiency of methanol oxidation catalyst. MCO is the phenomenon that liquid fuel permeates through polymer electrolyte membrane. TORAY has solved these problems by creating new membranes and developed innovative membrane electrode assembly (MEA) toward high efficiency DMFC systems.

Alkali complex hydrogen storage materials are expected as a material with large hydrogen storage capacity. However, small hydrogen reaction rate even at higher temperature obstructs the practical utilization. In this study, we investigated the effect of carbon nanotube mixing on the hydrogen reactivity of alkali complex hydrogen storage materials, where the CNT may enlarge the diffusion path in the sample particles. Sample preparation and CNT mixing was carried out using a mechanical alloying. The milling was carried out in two steps because of avoiding the alkali carbide formation. Reaction kinetics was improved by increasing amount of CNT mixing. On the other hand, the hydrogen amount absorbed was decreased with increase of CNT. Alkali carbide formed by the milling decreased the amount of absorbed hydrogen.

Due to the progress in fuel cell technology the demand for developing new catalysts for hydrogen production increases. Hence, in this study hydrogen production by oxidative steam reforming of n-butane was investigated over metal oxides supported base metal catalysts. Ni and Co catalysts provided high activity for combustion and subsequent reforming of n-butane. On the other hand, dehydrogenation was favored more than reforming over Cu, and Fe catalysts. Consequently Ni catalyst exhibited highest n-butane conversion (92%), which induced only insignificant amount of carbon deposited during the reaction. Furthermore, influence of support was investigated for Ni catalysts. All the catalysts showed 70-90% of initial n-butane conversions. However, catalytic stabilities were dependent on the kinds of supports. The stabilities of Ni/Al₂O₃, Ni/TiO₂ and Ni/SiO₂ were lower than that of Ni/MgO. Only Ni/MgO showed high and stable activity for 15h. These results reveal that Ni/MgO is one of the good candidates for oxidative reforming of n-butane.

In order to clarify how a co-existing gas such as water vapor, carbon monoxide, carbon dioxide or methane affects the hydrogen permeability of Ag 23wt%-Pd membrane of 20 μm in thickness, hydrogen permeation measurements were carried out. The hydrogen permeation fluxes were reduced when the co-existing gas was introduced together with hydrogen. By a precise analysis of the surface reaction, an empirical rate equation of the surface reaction has been proposed as functions of temperature, partial pressure and the components of the co-existing gas. The hydrogen permeation flux at 873 K was estimated using the rate equation obtained for the surface reaction with the co-existing gas. It was suggested that the co-existence of water vapor affects the hydrogen permeability the most. The interference effect of the co-existing gas is negligible for the membranes thicker than 10 μm. Due to slow surface reaction kinetics, the permeation flux does not increase inversely proportional to the membrane thickness. The permeation flux becomes saturating to a constant determined only by the surface reaction rate as the membranes thinned.