Lattice Gas Model for H2 Adsorption in Nanoporous Zinc Hexacyanometallates

Abstract

Zinc hexacyanometallates Zn3A2[M(CN)6]2 with different exchangeable alkaline cations A+ and framework transition metals M constitute an excellent model system to study H2 adsorption in nanoporous solids. A lattice gas approach, based on experimental data and simple considerations on the position and energies of adsorption sites, is proposed. Coverage and adsorption enthalpies are calculated and compared with experimental results. The interplay of three necessary conditions for H2 storage in porous solidssfree volume to accommodate guest molecules, charge centers to bind them, and fast diffusion during adsorption or desorptionsis discussed