Semi-experimental approach for hydrogen storage of as-produced zeolitic imidazolate framework-8 without post-processing

Low-cost hydrogen storage systems are essential for the widespread use of hydrogen, particularly in mobile platforms such as unmanned aerial vehicles, to increase their range. Hydrogen storage in metal–organic frameworks (MOFs), which offer high capacity through adsorption, is crucial to achieving this goal. This study investigates the hydrogen storage capacity of zeolitic imidazolate framework-8 (ZIF-8), produced via reactive extrusion, which allows for high production capacity and low-cost manufacturing of MOFs. Furthermore, particular attention was given to the storage capacity of ZIF-8 in its as-produced form. An atomistic model of the as-produced ZIF-8, including impurities selected from a series of simulated models containing different amounts of impurity, was developed. The validity of the selected structure was then verified through experimental powder X-ray diffraction and Brunauer–Emmett–Teller (BET) surface area measurements. Subsequently, hydrogen adsorption capacities for varying pressures and temperatures were calculated. The hydrogen adsorption simulations indicated that the atomistic model of the as-produced ZIF-8 exhibited a hydrogen storage capacity of 1.76 wt.% at 77 K and 1 bar, corresponding to a BET surface area of 516 m2/g. In comparison, the experimentally synthesized as-produced ZIF-8 showed a capacity of 1.145 wt.% under the same conditions, with a BET surface area of 520 m2/g. The study demonstrates that the gas storage performance of experimentally produced structures, even without further purification, can be accurately determined through simulation models in this semi-experimental study.