Large surface area nano structures for hydrogen storage

Physi-sorption is one promising way for storing hydrogen in lightweight materials with high specific surface area. Compared to chemisorption the process is fast and completely reversible involving low adsorption energies. Therefore, in the last years a lot of effort has been put in optimizing the surface texture of the adsorbents and in developing new materials with high micro-porosity. This chapter will give an overview about hydrogen storage in nano-structures with high specific surface area (SSA) focusing on different carbon structures, zeolites, and metal-organic frameworks. The experimental results give clear evidence that the hydrogen storage capacity of carbon materials is strongly dependent on their SSA and pore volume both at room temperature and at 77 K. Finally, the hydrogen adsorption isotherms of the metal-organic framework MOF-5 at room temperature and 77 K are discussed and an overview on new results of hydrogen storage in MOFs is given. (authors)