Jump to Main Content
Diffusion of molecular hydrogen in carbon aerogel
- Bahn, Emanuel, Czakkel, Orsolya, Nagy, Balázs, László, Krisztina, Villar-Rodil, Silvia, Tascón, Juan M.D., Demmel, Franz, Telling, Mark T.F., Fouquet, Peter
- Carbon 2016 v.98 pp. 572-581
- activated carbon, hydrogen, temperature
- The diffusion of hydrogen molecules adsorbed in a highly porous carbon aerogel has been studied with quasi-elastic neutron scattering. Hydrogen diffusion in this carbon substrate followed an activated jump process with a single activation barrier. The temperature dependence of the diffusion rate agrees well with previous results from activated carbons and other highly porous carbons. The carbon aerogel sample showed a strongly enhanced conversion between the ortho- and para-hydrogen spin states. The ortho-para conversion process, however, was inhibited for a fraction of the hydrogen molecules. This inhibition process is attributed to a rotational confinement of the hydrogen molecules at the nanometre scale.