Non-Interpenetrated 3D Covalent Organic Framework with Dia Topology for Au Ions Capture

The 3D covalent organic frameworks (COFs) have attracted considerable attention owing to their unique structural characteristics. However, most of 3D COFs have interpenetration phenomena, which will result in decreased surface area and porosities, and thus limited their applications in molecular/gas capture. Developing 3D COFs with non-fold interpenetration is challenging but significant because of the existence of non-covalent interactions between the adjacent nets. Herein, a new 3D COF (BMTA-TFPM-COF) with dia topology and non-fold interpenetration for Au ion capture is first demonstrated. The constructed COF exhibits a high Brunauer–Emmett–Teller surface area of 1924 m² g⁻¹, with the pore volume of 1.85 cm³ g⁻¹. The high surface area and abundant cavities as well as the abundant exposed C=N linkages due to the non-interpenetration enable to absorb Au³⁺ with high capacity (570.18 mg g⁻¹), selectivity (99.5%), and efficiency (68.3% adsorption of maximum capacity in 5 min). This work provides a new strategy to design 3D COFs for ion capture.