CO2, CH4, and H2 Adsorption Performance of the Metal-Organic Framework HKUST-1 by Modified Synthesis Strategies

High-pressure adsorption of CO2, H2, and CH4 has several applications, including CO2 capture, methane, and hydrogen storage. The performance ultimately depends on the adsorbent design. Herein, we report a comparative assessment of a Cu-metal-organic framework (MOF) (HKUST-1) by conventional hydrothermal synthesis and its modified analogues, HKUST-N with NH4OH and HKUST-Ca with Ca(NO3)2, for CO2, CH4, and H2 adsorption. The materials showed high CO2 (12 mol/Kg), CH4 (2.5-4 mol/Kg), and H2 (0.4-0.8 mol/Kg) capacities at 50 bar. Owing to different synthesis strategies, the differences in surface area, pore size distribution, morphology, and the presence of calcium species in HKUST-Ca considerably impacted CH4 and H2 adsorption, leading to considerable differences in selectivities for various gas mixtures. This work establishes a clear correlation of subtle modifications in synthesis strategies of the MOF HKUST-1 on its morphological characteristics and CO2, CH4, and H2 adsorption performance.