Chemically Modified HKUST-1(Cu) for Gas Adsorption and Separation: Mixed-Metal and Hierarchical Porosity

The archetypical metal-organic framework (MOF), HKUST-1, has been systematically modified in both its organic and inorganic building blocks to introduce diversity in the metal centers and create defects within the network, achieving a variety of bimetallic hierarchical structures. These modifications changed the affinity of the MOFs for acid gases. The introduction of bimetallic sites mostly affects CO₂ adsorption, while the hierarchical structure generates an increase in SO₂ uptake capacity, allowing better performance in the separation of binary mixtures of these gases near room temperature. Notably, the synthesized HH-Cu₁₀₀ material exhibited an exceptionally high IAST SO₂/CO₂ (10:90) selectivity of 3420 at 298 K, outperforming benchmark MOFs with open metal sites.