Chemical−Clathrate Hybrid Hydrogen Storage: Storage in Both Guest and Host

Abstract

Hydrogen storage from two independent sources of the same material represents a novel approach to the hydrogen storage problem, yielding storage capacities greater than either of the individual constituents. Here we report a novel hydrogen storage scheme in which recoverable hydrogen is stored molecularly within clathrate cavities as well as chemically in the clathrate host material. X-ray diffraction and Raman spectroscopic measurements confirm the formation of beta-hydroquinone (beta-HQ) clathrate with molecular hydrogen. Hydrogen within the beta-HQ clathrate vibrates at considerably lower frequency than hydrogen in the free gaseous phase and rotates nondegenerately with splitting comparable to the rotational constant. Compared with water-based clathrate hydrate phases, the beta-HQ+H2 clathrate shows remarkable stability over a range of p-T conditions. Subsequent to clathrate decomposition, the host HQ was used to directly power a PEM fuel cell. With one H2 molecule per cavity, 0.61 wt % hydrogen may be stored in the beta-HQ clathrate cavities. When this amount is combined with complete dehydrogenation of the host hydroxyl hydrogens, the maximum hydrogen storage capacity increases nearly 300% to 2.43 wt %.

Fast and reversible hydrogen storage in channel cages of hydroquinone clathrate

“…Much effort has been devoted to finding the best materials for hydrogen storage such as metal organic framework (MOF), metal hydride, and carbon nanotubes [1]. The use of clathrate compounds as potential hydrogen storage materials has attracted considerable attention recently [2][3][4][5][6][7]. In particular, the hydroquinone (HQ) clathrate has been recognized as one of the potential host media for hydrogen storage, because they often form stable cage-like structures at ambient condition [5][6][7].…”

“…A recent MD study indicates that H 2 molecules can be stored in the cage-like networks of the HQ clathrate [5]. However, in situ synthesis of the HQ clathrate with gaseous H 2 requires very high pressure of $200 MPa [6].…”

Thermodynamic Properties of Hydrogen + Tetra-n-Butyl Ammonium Bromide Semi-Clathrate Hydrate

“…Recently, gas hydrates and other clathrate materials [1] have become one of attractive media that have a huge potential for effective applications of H 2 storage and transportation. The H 2 -mixed gas hydrates with the assistance of suitable additives enable us to perform the H 2 storage under much lower-pressure conditions than the simple H 2 hydrate [2].…”

Decomposition kinetics and recycle of binary hydrogen‐tetrahydrofuran clathrate hydrate

“…The potential of tetrahydrofuran (THF) clathrate hydrates for hydrogen (H 2 ) storage continues to be of interest, where it has been demonstrated with precise measurements that THF hydrate can store up to 1.6 mol H 2 /mol THF (0.045 g H 2 /g THF) at 277.15 K and 70 MPa 1. Moreover, there is the possibility for using other guest molecules2, 3 or hybrid structures4 that could allow achievement of greater H 2 storage capacities, since current storage capacity is considered to be low for practical applications 5…”