First-Principles study on CO, CO2 and CH4 capture on Mg-MOF-74

Abstract

In this work, the loading capacity of Mg-MOF-74 is evaluated for carbon-containing gases specifically for carbon monoxide (CO), carbon dioxide (CO₂), and methane (CH₄) using the density functional theory as implemented in the Gaussian-09 and Quantum ESPRESSO suites of the programs. The results show that the loading capacity of Mg-MOF-74 for CO is 14.6 mmol/g and that for CO₂, and CH₄ molecules is, 10.9 mmol/g. The gas-to-MOF ratios for CO, CO₂, and CH₄ molecules in the loaded MOFs are found to be 0.41, 0.48, and 0.18, respectively, suggesting that 1 g of Mg-MOF-74 may absorb 0.41 g of CO, 0.48 g of CO₂, and 0.18 g of CH₄ gas. Therefore, this study revealed that Mg-MOF-74 has outstanding adsorption capacity for carbon-containing gases and could be one of the promising materials for mitigating global warming and environmental pollution. Moreover, the findings revealed that the MOF's reactivity decreases and becomes increasingly stable as the number of loaded molecules increases, indicating that the saturated MOF is more stable than the unsaturated MOF.