Salt-Templated Solvothermal Synthesis of Dioxane-Linked Three-Dimensional Nanoporous Organic Polymers for Carbon Dioxide and Iodine Capture

Precise control over the textural properties of porous organic polymers, POPs, is a daunting task, yet highly important to achieve the desired porosity and pore connectivity for target applications. Accordingly, the introduction of hard templates in the solvothermal synthesis of POPs could help to control the surface area and pore size without altering their chemical structure. In this direction, here we synthesized a dioxane-linked three-dimensional tetraphenylene-based nanoporous organic polymer (3D-tPOP) using low-cost and readily available NaCl salt as a hard template under solvothermal conditions. The presence of a hard template enhanced the surface area and enabled control over the morphology, micropore/mesopore ratio, and pore volume with respect to the template amount. Whereas micron-sized NaCl templates facilitated the surface growth of a microporous polymer network, nanosized NaCl crystallites led to the formation of mesopores. The resulting 3D-tPOPs showed tunable micropore/mesopore ratios and surface areas in the range of 349-1058 m(2 )g(-1) with a linear correlation to the template amount. A high CO2 uptake capacity of 5.02 mmol g(-1) at 273 K and 1 bar and an I-2 uptake capacity of 1180 mg g(-1) were observed for 3D-tPOPs with micropore and mesopore ratios of 50.2% and 71.4%, respectively.