Porous Metal-Organic Frameworks: Promising Materials for Methane Storage  Bin Li, Hui-Min Wen, Wei Zhou, Jeff Q. Xu, Banglin Chen  Chem  Volume 1, Issue 4, Pages 557-580 (October 2016) DOI: 10.1016/j.chempr.2016.09.009 Copyright © 2016 Elsevier Inc. Terms and Conditions

Chem 2016 1, 557-580DOI: (10.1016/j.chempr.2016.09.009) Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 1 Crystal Structures and Salient Pore Metrics of the MOFs under Consideration X-ray crystal structure of HKUST-1 (A), UTSA-76 (B), NOTT-102 (C), and NU-111 (D). The gray, red, cyan, and blue spheres represent carbon, oxygen, copper, and nitrogen atoms, respectively. The bigger yellow, green, and blue spheres denote the pores within the frameworks. The hydrogen atoms are omitted for clarity. Chem 2016 1, 557-580DOI: (10.1016/j.chempr.2016.09.009) Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 2 Comparison of Total Gravimetric and Volumetric CH4 Uptake for MOF Materials at 270 and 298 K (A) Total gravimetric CH4 uptake (65 bar, g [CH4] g−1). (B) Total volumetric CH4 uptake (cm3 [STP] cm−3). The horizontal gray lines in (A) and (B) represents the new gravimetric and volumetric DOE targets, respectively. Chem 2016 1, 557-580DOI: (10.1016/j.chempr.2016.09.009) Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 3 Schematic Diagram of the Determination of the Amount of Deliverable Methane Storage with MOF-177 as an Example Chem 2016 1, 557-580DOI: (10.1016/j.chempr.2016.09.009) Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 4 Comparison of Working Capacities at 5–65 bar and Different Storage Temperatures Selected MOFs at 270 and 298 K (A–C) and 240, 270, and 298 K (D–F) with different ranges of pore volume: 0.5–0.9 cm3 g−1 (A and D), 0.9–1.3 cm3 g−1 (B and E), and 1.3–2.4 cm3 g−1 (C and F). Chem 2016 1, 557-580DOI: (10.1016/j.chempr.2016.09.009) Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 5 Working Capacity versus Pore Volume The working capacity (cm3 [STP] cm−3) of MOFs systematically increases with increased pore volume (Vp, cm3/g). Chem 2016 1, 557-580DOI: (10.1016/j.chempr.2016.09.009) Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 6 Calculation of the Excess Methane Storage Capacity of a Specific MOF at 270 K and 65 bar (A) Saturated excess gravimetric methane adsorption capacity at 125 K (cm3 [STP] g−1) versus pore volume (cm3 g−1) of the MOFs investigated. (B) Pore occupancy versus pore volume (cm3 g−1). Pore occupancy is defined as the excess gravimetric methane uptake at 270 K and 65 bar divided by the saturated excess gravimetric methane uptake at 125 K. The solid lines show the linear fitting results. Chem 2016 1, 557-580DOI: (10.1016/j.chempr.2016.09.009) Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 7 Comparison of the Experimental Total Methane Uptake and Those Predicted by the Empirical Equation (A) Gravimetric methane uptake at 270 K and 65 bar. (B) Volumetric methane uptake at 270 K and 65 bar. The framework densities used here were obtained from crystal structures without guest and terminal molecules. Chem 2016 1, 557-580DOI: (10.1016/j.chempr.2016.09.009) Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 8 Comparison of the Predicted Volumetric Uptake at 270 and 298 K The plot of the total volumetric methane storage capacity (cm3 [STP] cm−3) at 65 bar and 270 K (red) or 298 K (black) versus the framework pore volume (Vp, cm3 g−1) according to the empirical equations. The blue arrow indicates that the calculated limitation of methane storage of MOF materials at 65 bar is significantly improved and the pore volume is higher when the storage temperature is reduced from 298 K to 270 K. Chem 2016 1, 557-580DOI: (10.1016/j.chempr.2016.09.009) Copyright © 2016 Elsevier Inc. Terms and Conditions