Rapid and Large-Scale Synthesis of High-Crystalline Imide Covalent Organic Frameworks Accelerated by Self-Generated Water.

Imide covalent organic frameworks (COFs) are considered promising materials in various fields due to their exceptional stability, large surface area, and high porosity. However, current synthesis methods of imide COFs typically involve complex vacuum operations, large amounts of solvents, and long reaction times at high temperatures, limiting their scalability for industrial production. Herein, a facile self-accelerated strategy is developed for rapid, low-cost, and large-scale synthesis of eight imide COFs (SACOFs) under solvent-free, vacuum-free, and low-temperature conditions. Mechanistic studies reveal that the self-accelerated synthesis is driven by the self-generated water under atmospheric conditions, which accelerates the reversible self-healing of disordered polymers, ultimately leading to the rapid synthesis of highly crystalline COFs. Notably, the only additive required besides the COF monomers is o-substituted benzoic acid, a small amount of which is grafted onto the imide COFs, enabling their straightforward functionalization. Thiol-functionalized SACOFs are synthesized as supports for anchoring Pd nanoparticles. The as-prepared Pd@SACOFs exhibit high activity and selectivity in the hydrogenation of substituted nitrobenzene due to the surface modulation of Pd by thiol groups. The self-accelerated synthetic strategy enables rapid, low-cost, and large-scale production of imide COFs, potentially paving the way for their transition from laboratory research to commercial applications.