Surface Area and Porosity of Co3(ndc)3(dabco) Metal-Organic Framework and Its Methane Storage Capacity: A Combined Experimental and Simulation Study

Metal-organic frameworks (MOFs) are among the porous materials with the highest potential for adsorptive methane (CH4) storage. Here, we combine experimental measurements with molecular simulations to characterize the surface area and porosity of Co3(ndc)3(dabco) - a very interesting but less studied MOF - and to assess its CH4 adsorption capacity. The experiments cover the pressure and temperature ranges of 0-30 bar and 273-323 K, respectively. The MOF's specific pore volume and surface area are determined using various approaches based on geometrical considerations and molecular simulations. The limitations and advantages of each approach are discussed. The experimental data are in excellent agreement with purely predictive molecular simulations using a force field based almost exclusively on the TraPPE-UA force field. The evaluation of the volumetric adsorption capacity of Co3(ndc)3(dabco) confirms that it is indeed a good candidate for CH4 storage. For a charge pressure of 35 bar and a delivery pressure of 5 bar, Co3(ndc)3(dabco) has a CH4 working capacity of 93 v/v (the amount of stored CH4 measured as volume of gas under standard temperature and pressure conditions per volume of MOF) at room temperature, which is close to the performance of other promising materials such as MOF-5, MOF-177, and MOF-205.