Methane Hydrate Formation in Hollow ZIF-8 Nanoparticles for Improved Methane Storage Capacity

Abstract

Methane hydrate has been extensively studied as a potential medium for natural gas storage and transportation. Due to their high specific surface area, tunable porous structure, and surface chemistry, metal–organic frameworks are ideal materials to exhibit the catalytic effect for the formation process of gas hydrate. In this paper, hollow ZIF-8 nanoparticles are synthesized using the hard template method. The synthesized hollow ZIF-8 nanoparticles are used in the adsorption and methane hydrate formation process. The effect of pre-adsorbed water mass in hollow ZIF-8 nanoparticles on methane storage capacity and the hydrate formation rate is investigated. The storage capacity of methane on wet, hollow ZIF-8 is augmented with an increase in the mass ratio of pre-adsorbed water and dry, hollow ZIF-8 (RW), and the maximum adsorption capacity of methane on hollow ZIF-8 with a RW of 1.2 can reach 20.72 mmol/g at 275 K and 8.57 MPa. With the decrease in RW, the wet, hollow ZIF-8 exhibits a shortened induction time and an accelerated growth rate. The formation of methane hydrate on hollow ZIF-8 is further demonstrated with the enthalpy of the generation reaction. This work provides a promising alternative material for methane storage.