Controlling hydrogen release from remaining-intact Clathrate hydrates by electromagnetic fields: molecular engineering via microsecond non-equilibrium molecular dynamics.

In view of the recently-predicted hydrogen release from type-II (sII) clathrate hydrates in the general 140-180 K temperature range [ J. Phys. Chem. C , 125 , 8430-8439 (2021)], we have investigated in the present study, by means of microsecond-long non-equilibrium molecular-dynamics simulation, the effect of externally-applied electric fields (both static and alternating) on manipulating and accelerating this H 2 -escape process. In particular, we have found that judiciously-selected electromagnetic fields, in the microwave frequency range, serve to enhance dramatically this H 2 -release rate - crucially, without any breakup of the hydrate lattice itself . Of those studied, we have found that 10 GHz serves as the optimal frequency to maximise hydrogen release, owing to promotion of H 2 -H 2 molecular collisions inside doubly-occupied 5 12 6 4 cages in the sII structure and optimal field-period overlap with intra-cage tetrahedral-site hopping and opportunities for inter-cage passage via hexagonal cage faces. This study opens up the vista of "field engineering" for exquisite kinetic control of large, Grid-(terawatt hour)-scale hydrogen-storage systems.