Nanoporous Benzoxazole Networks by Silylated Monomers, Their Exceptional Thermal Stability, and Carbon Dioxide Capture Capacity

The pursuit of synthetic routes for design and preparation of nanoporous polymeric networks with inherent permanent microporosity and functionality through bottom-up methodologies remains a driving force in developing CO₂-philic materials. We report nanoporous, processable, benzoxazole-linked covalent organic polymers (Box-COPs) that show exceptional thermal stability up to 576 °C. Box-COPs can be formed into films thanks to the silylation that is used to guide polymeric network formation. Surface areas of up to 606 m² g^–1 and narrow pore sizes of 4.36 Å were observed with a CO₂ uptake capacity of 139.6 mg g^–1 at 273 K and 1 bar. Box-COPs were stable in boiling water for a week without deteriorating CO₂ capture capacity

Cesium Ion-Mediated Microporous Carbon for CO2 Capture and Lithium-Ion Storage

Activated carbon has been used in a wide range of applications owing to its large specific area, facile synthesis, and low cost. The synthesis of activated carbon mostly relies on potassium hydroxide (KOH)-mediated activation which leads to the formation of micropores (<2 nm) after a washing step with acid. Here we report the preparation of activated carbon with an anomalously large surface area (3288 m(2) g(-1)), obtained by employing an activation process mediated by cesium (Cs) ions. The high affinity of the carbon lattice for Cs ions induces immense interlayer expansion upon complexation of the intercalant Cs ion with the carbon host. Furthermore, the Cs-activation process maintains the nitrogen content of the carbon source by enabling the activation process at low temperature. The large surface area and well-preserved nitrogen content of Cs-activated carbon takes advantage of its enhanced interaction with CO2 molecules (for superior CO2 capture) and lithium ions (for improved Li ion storage), respectively. The present investigation unveils a new approach toward tuning the key structural properties of activated carbon; that is, controlling the affinity of the carbon host for the intercalant ion when they engage in complex formation during the activation process.