The influence of textural properties on the adsorption of hydrogen on ordered nanostructured carbons

The design of an efficient hydrogen storage device is a major key point for the development of this fuel in mobile applications. Hydrogen physisorption on porous carbon materials is one among the different technologies which could be used. Although numerous types of carbon materials have been tested, the hydrogen adsorption capacities measured are far from reaching the goal proposed by the US DOE for transportation applications, that is 6.5wt.% at room temperature. In this study, ordered mesoporous carbon materials were synthesized by replication from organized mesoporous silicas. The combination of different templates and carbon precursors allowed to vary the textural properties of the samples. These materials were characterized by nitrogen and carbon dioxide adsorption, and their hydrogen storage capacity was measured at 77 K between 0.1 and 1 MPa. The best result was obtained by using sucrose as carbon precursor. The hydrogen weight percentage correlate well with the microporous volume determined by applying Dubinin-Radushkevich equation on CO2 adsorption isotherms showing the importance of ultramicropores (pore diameters below 1 nm). The evaluation of hydrogen density in the porous structure of the material shows also that there is a significant storage in supermicropores with diameters between 1 and 2 nm. (c) 2004 Elsevier Inc. All rights reserved.