Ultrafast sonochemical synthesis of imine-linked porous organic cages with high surface area for gas adsorption

Abstract

Porous organic cages (POCs) are promising crystalline porous materials with high porosity, but their conventional solvothermal synthesis is time-consuming and energy-intensive. Herein, we report for the first time an ultrafast sonochemical approach (<5 minutes, ambient temperature) for synthesizing imine-linked POCs (Sono-CC3R-OH, Sono-CC3R, and Sono-NC2R) using methanol as a green solvent. The sonochemically synthesized POCs exhibit exceptional porosity and crystallinity, outperforming their solvothermal counterparts, while achieving a ∼78% reduction in energy consumption. Furthermore, this approach exhibits excellent potential for large-scale production and efficient solvent recyclability. High-surface-area Sono-CC3R-OH demonstrates preferable CO₂ adsorption with a CO₂/N₂ selectivity of up to 77.5. Thus, this work opens a quick and efficient pathway for the synthesis of imine-linked POCs with superior surface area, offering great potential for the scalable production of gas adsorbents.