One-pot synthesis of sulfonic acid functionalized Zr-MOFs for rapid and specific removal of radioactive Ba2

Structural Compromise Between Conflicted Spatial-Arrangements of Two Linkers in Metal-Organic Frameworks

The structural control of metal-organic frameworks (MOFs) is essential for the development of superlative MOFs because the structural features of MOFs and their components play a critical role in determining their properties, and ultimately, their applications. The best components to endow the desired properties for MOFs are available via the appropriate choice from many existing chemicals or synthesizing new ones. However, to date, considerably less information exists regarding fine-tuning the MOF structures. Herein, a strategy for tuning MOF structures by merging two MOF structures into a single MOF, is demonstrated. Depending on the incorporated amounts and relative contributions of the two coexisting organic linkers, benzene-1,4-dicarboxylate (BDC^2- ) and naphthalene-1,4-dicarboxylate (NDC^2- ), which have conflicting spatial-arrangement preferences within an MOF structure, MOFs are rationally designed to have a Kagomé or rhombic lattice. In particular, MOFs with rhombic lattices are constructed to have specific lattice angles by compromising the optimal structural arrangements between the two mixed linkers. The relative contributions of the two linkers during MOF construction determine the final MOF structures, and the competitive influence between BDC^2- and NDC^2- is effectively regulated to produce specific MOF structures with controlled lattices.

Enhance Hydrogen Isotopes Separation by Alkali Earth Metal Dopant in Metal-Organic Framework

Kinetic quantum sieving (KQS) based on pore size and chemical affinity quantum sieving (CAQS) based on adsorption site are two routes of porous materials to separate hydrogen isotope mixtures. Alkali earth metals (Be, Mg, and Ca) were doped into UiO-67 to explore whether these metal sites can promote H₂/D₂ separation. Based on the zero-point energy and adsorption enthalpy calculated by density functional theory calculations, the Be dopant shows better H₂/D₂ separation performance than other alkali earth metal dopants and unsaturated metal sites in metal-organic frameworks based on CAQS. Orbital interaction strongly relates to the chemical affinity and further influences the D₂/H₂ selectivity. Moreover, the predicted D₂/H₂ selectivity of Be-doped sites (49.4) at 77 K is even larger than the best experimental result (26). Finally, the different dynamic behaviors of H₂ and D₂ on Be-doped UiO-67 indicate its strong H₂/D₂ separation performance via KQS.