Nanosponges for hydrogen storage

The usable capacity of porous materials for hydrogen storage

“…Of these materials, DUT-23 exhibits the lowest enthalpy, starting at 4.2 kJ/mol and decreasing almost linearly to 3.5 kJ/mol with increasing coverage indicating that all adsorption sites possess a similar binding strength. According to the structural analysis DUT-23(Co) mainly possesses large pores of 2.4 nm diameter [23] resulting in a rather low enthalpy of adsorption [13]. In contrast to DUT-23(Co), Fe-BTC-Gel has an amorphous structure with pores mainly Fig.…”

“…The saturation uptake was found to be proportional to the specific surface area [9,10] and to the micropore volume [10][11][12]. The pore diameter seems to have a strong influence on the average enthalpy of adsorption [13][14][15], which in turn determines the temperature dependence of the hydrogen uptake. Nevertheless, in this work a great variety of different structures is evaluated for making sure that the results about the usable capacity are representative for all materials.…”

Liquid-like hydrogen in the micropores of commercial activated carbons

“…In the case of hydrogen for example, it is verified that, at liquid nitrogen temperature (77 K) there is a quite linear correlation between the hydrogen uptake and the available surface area (SSA) [23]. Nevertheless an important role is covered by the pore morphology, indeed this relation is disobeyed when the pores diameter are in the same order of magnitude of adsorbed molecule width: an enhancement of the net attractive force occurs, due to the overlap of opposed pore walls potential [6,8,24]. In the case of hydrogen, for example, the best adsorption is observed on microporous (pore width < 20 Å ) and ultra-microporous (pore width < 7 Å ) [19,25e27].…”

“…The adsorption process, named physisorption, occurs when a gas molecule approaching to surfaces binding-site is weakly linked by van der Waals forces, avoiding molecules dissociation or chemisorption processes [6,7].…”

Volumetric Hydrogen Storage Capacity in Metal–Organic Frameworks

“…For the next generation of fuel‐cell vehicles, the automotive industry is still looking for more cost‐efficient methods to store hydrogen safely. Physisorption of hydrogen on porous structures may be one solution for systems with much lower operating pressures . Owing to the low interaction energy of approximately 5 kJ mol −1 for hydrogen adsorption, only at low temperatures a type I isotherm is observed.…”