Classical density functional theory reveals structural information of H2 and CH4 fluids adsorbed in MOF-5

This study employs classical Density Functional Theory (cDFT) to investigate the adsorption isotherms and structural information of H2 and CH4 fluids inside MOF-5. The results indicate that the adsorption of both fluids is highly dependent on the fluid temperature and the shape of the MOF-5 structure. Specifically, the CH4 molecules exhibit stronger interactions with the MOF-5 framework, resulting in a greater adsorbed quantity compared to H2. Additionally, the cDFT calculations reveal that the adsorption process is influenced by the fluid-fluid spatial correlations between the fluid molecules and the external potential produced by the MOF-5 solid atoms. These findings are supported by comparison with experimental data of adsorbed amount and the structure factor of the adsorbed fluid inside the MOF-5. We demonstrate the importance of choosing the appropriate grid size in calculating the adsorption isotherm and the fluid structure factors within the MOF-5. Overall, this work provides valuable insights into the adsorption mechanism of H2 and CH4 in MOF-5, emphasizing the importance of considering the structural properties of the adsorbed fluids in MOFs for predicting and designing their gas storage capacity at different thermodynamic conditions.

Automated summary

This study used classical Density Functional Theory to investigate the adsorption isotherms and structural information of H2 and CH4 fluids in MOF-5. The results show that the adsorption process is influenced by fluid temperature and the shape of the MOF-5 structure. CH4 molecules have stronger interactions with the MOF-5 framework, resulting in a higher adsorbed quantity compared to H2. The study emphasizes the importance of considering the structural properties of adsorbed fluids in MOFs for predicting gas storage capacity at different thermodynamic conditions.