Outlook and challenges for hydrogen storage in nanoporous materials

Considerable progress has been made recently in the use of nanoporous materials for hydrogen storage. In this article, the current status of the field and future challenges are discussed, ranging from important open fundamental questions, such as the density and volume of the adsorbed phase and its relationship to overall storage capacity, to the development of new functional materials and complete storage system design. With regard to fundamentals, the use of neutron scattering to study adsorbed H2, suitable adsorption isotherm equations, and the accurate computational modelling and simulation of H2 adsorption are discussed. The new materials covered include flexible metal-organic frameworks, core-shell materials, and porous organic cage compounds. The article concludes with a discussion of the experimental investigation of real adsorptive hydrogen storage tanks, the improvement in the thermal conductivity of storage beds, and new storage system concepts and designs.Scopu

Monitoring adsorption by small angle neutron scattering in tandem with digital reconstruction-simulation techniques

International audienc

The structure of adsorbed CO2 in carbon nanopores: a neutron diffraction study

The behaviour of CO2 adsorbed on a nticroporous carbon at a temperature slightly above the critical point, was studied by adsorption in conjunction with in situ neutron powder diffraction. The carbon sample was produced by carbonisation and activation of a polymer precursor and the experiment was carried out by means of a specially designed adsorption apparatus, directly mounted on the neutron diffractometer. The CO2 diffraction patterns provide evidence that the adsorbed phase is-at pressures well below the critical one-in a state comparable to high-pressure dense supercritical fluid or even bulk liquid. Furthermore, the features of the diffraction patterns are consistent with the presence of orientational correlations between adsorbed molecules. Even though, the scattering data cover a limited Q space and thus the overall resolution is rather poor, the radial distribution functions deduced at different equilibrium pressures, reveal differences, which could be attributed to changes in the arrangement of CO2 molecules along the 308 K isothermal scan. The results are discussed and compared with permeability measurements as well as Monte Carlo calculations. (C) 2004 Elsevier B.V. All rights reserved

Hydrogen storage properties of Pd-doped thermally oxidized single wall carbon nanohorns.

Single wall carbon nanohorns as well as their thermally oxidized derivatives were decorated with Pd nanoparticles and their H2 sorption performance was examined at 298 K up to 20 bar. The specific surface area of the nanohorns was increased through air oxidation, while both the thermal treatment and the metal doping led to the enhancement of the H2 uptake. The higher uptake of the hybrid materials could not be attributed only to the additive effect of the carbon support and Pd content suggesting the existence of a cooperative mechanism between the metal particles and the carbon surface. This weak chemisorption process was found to be fully reversible after mild heating; still, its contribution to the overall H2 uptake was not found to be of great significance