Hydrogen and methane storage and release by MoS2 nanotubes for energy storage

Abstract

Using molecular dynamics simulations, we investigate the performance of molybdenum disulfide nanotubes (MoS₂ NTs) as a medium for energy gas storage (hydrogen and methane). Two representative MoS₂ NTs, (12, 12) and (6, 6), are considered in our present study. MoS₂ NTs are found to effectively attract hydrogen and methane molecules through their surface and interior. Under storage conditions (175 K and 10 MPa), the storage capacity of methane in MoS₂ NTs can reach 7–8 wt%, depending on the diameter of MoS₂ NTs. For hydrogen, the storage capacity is around 0.7–0.9 wt%. The gas weight percentage is linearly dependent on the environmental pressure from 10 MPa to 1 MPa at constant temperature. Meanwhile, adsorption demonstrates an exponential relationship with the system temperature from 175 K to 425 K when pressure is maintained constant. Dynamic pressure simulations reveal that up to 80–90% of the stored gases can be spontaneously released as the pressure decreases from 10 MPa to 1 MPa, with methane slightly more efficient than hydrogen, indicating high cyclic storage performance. Our present theoretical findings shed new light on the utilization of MoS₂ nanomaterials as a novel gas storage platform and we hope our results will promote future experimental efforts.