Assessment of hydrogen storage by physisorption in porous materials

Abstract

As a basis for the evaluation of hydrogen storage by physisorption, adsorption isotherms of H 2 were experimentally determined for several porous materials at 77 K and 298 K at pressures up to 15 MPa. Activated carbons and MOFs were studied as the most promising materials for this purpose. A noble focus was given on how to determine whether a material is feasible for hydrogen storage or not, dealing with an assessment method and the pitfalls and problems of determining the viability. For a quantitative evaluation of the feasibility of sorptive hydrogen storage in a general analysis, it is suggested to compare the stored amount in a theoretical tank filled with adsorbents to the amount of hydrogen stored in the same tank without adsorbents. According to our results, an ''ideal'' sorbent for hydrogen storage at 77 K is calculated to exhibit a specific surface area of >2580 m 2 g À1 and a micropore volume of >1.58 cm 3 g À1 .

Supercritical Fluids in Confined Geometries

“…These findings were supported by theoretical calculations, using first-principle methods of treating the van der Waals interactions within density functional theory, which confirmed that H 2 density in subnanometer pores indeed could reach a liquidlike density even at 50 bar and 298 K [63,64]. The described SAS results demonstrate the advantage of adsorptive storage over compressed gas storage and emphasize the greater efficiency of micropores over mesopores in the adsorption process [65].…”

Tailoring Graphene Oxide‐Based Aerogels for Efficient Solar Steam Generation under One Sun

“…Aerogels are emerging as one novel kind of porous solids with many fascinating properties such as low mass density, high porosity, large surface area, and low thermal conductivity. Since the first study by Kistler in 1930s, various kinds of aerogels such as silica aerogels, metal aerogels, polymer aerogels, and carbon aerogels have been fabricated, with promising applications in energy storage, catalysis, hydrogen storage, and CO 2 adsorption . In this work, for the first time we demonstrate that graphene oxide (GO)‐based aerogels with carefully tailored absorption, thermal, and hydrophilic properties can enable efficient (≈83%) solar steam generation under one‐sun illumination.…”

Outlook and challenges for hydrogen storage in nanoporous materials

“…It is also worth noting the importance of considering the usable or deliverable capacity of a material [61,[147][148][149][150][151][152], rather than just its total or absolute capacity (as discussed in Sect. 2.2).…”