2007: A GRAND CANONICAL MONTE-CARLO STUDY OF H2 ADSORPTION IN PRISTINE AND Li-DOPED CARBON REPLICAS OF FAUJASITE ZEOLITE

The first step of this work was to generate using atomistic simulation, a porous carbon material with an ordered pore network using the faujasite Y zeolite as a templating matrix. For this purpose, we used the Grand Canonical Monte-Carlo (GCMC) technique in which the carbon-carbon interactions were described with reactive bond-order potential assuming the carbonzeolite interactions to be relevant to physisorption. The intrinsic stability of the nanoporous carbon material was then investigated. We also performed a structural analysis of the resulting carbon porous structure including the determination of the pore size distribution. Such a new carbon form has a very ordered porous structure that can be used as a model adsorbent to validate adsorption theory and characterization methods. At a second stage, we calculated for these pristine structures, hydrogen adsorption isotherms at different temperatures with the GCMC technique using ab initio adsorbate-carbon interaction potentials. Although our carbon replicas have an optimum pore size for H2 docking, we demonstrated that they cannot be used as for an efficient storage at room temperature under 300 bars. By contrast, when doped with lithium (LiC6), we found, that room temperature H2 storing become possible: we obtain 4% in weight (37 kg/m) under 300 bars. The origin of these good storing performances is to be found at the atomistic level thanks to the Li to C electron transfer.