Combinatorial Synthesis of Covalent Organic Framework Particles with Hierarchical Pores and Their Catalytic Application

Precise tailoring of the aggregationstate of covalent organicframeworks (COFs) to form a hierarchical porous structure is criticalto their performance and applications. Here, we report a one-pot andone-step strategy of using dynamic combinatorial chemistry to constructimine-based hollow COFs containing meso- and macropores. It relieson a direct copolymerization of three or more monomers in the presenceof two monofunctional competitors. The resulting particle productspossess high crystallinity and hierarchical pores, including microporesaround 0.93 nm, mesopores widely distributed in the range of 3.1-32nm, and macropores at about 500 nm, while the specific surface areacould be up to 748 m(2)& BULL;g(-1), withnon-micropores accounting for 60% of the specific surface area. Theparticles demonstrate unique advantages in the application as nanocarriersfor in situ loading of Pd catalysts at 93.8% loading efficiency inthe copolymerization of ethylene and carbon monoxide. The growth andassembly of the copolymer could thus be regulated to form flower-shapedparticles, efficiently suppressing the fouling of the reactor. Thecopolymer's weight-average molecular weight and the meltingtemperature are also highly improved. Our method provides a facileway of fabricating COFs with hierarchical pores for advanced applicationsin catalysis.

Automated summary

A one-pot and one-step strategy of using dynamic combinatorial chemistry is reported to construct imine-based hollow COFs with hierarchical pores. The resulting particles possess high crystallinity and hierarchical pores, making them useful nanocarriers for catalysis applications.