Nanoporous Polyporphyrin as Adsorbent for Hydrogen Storage

Novel polyporphyrins with high surface area over 1500 m(2)/g have been synthesized, and their hydrogen absorption capacities were measured. Porphyrin functionalized with thiophenyl groups was designed as starting monomer; the porphyrin cores offer coordination sites for metal ions which could potentially enhance the interaction with hydrogen for favorable hydrogen storage while the thiophenyl groups are used for cross-linking the monomers under oxidative coupling conditions to yield highly porous networks. These polyporphyrins adsorb up to 5.0 mass % H-2 at 77 K and 65 bar. Compared with metal free polymer, iron(II)-containing polymer shows finite increase in heat of adsorption for hydrogen, suggesting a promising approach for designing high heat of adsorption porous materials.