Sulfhydryl-functionalized covalent organic frameworks microspheres supported Au nanoparticles for continuous flow-through catalysis

The pore walls functionalization of covalent organic frameworks (COFs) allows for the immobilization of noble metal nanoparticles on the COFs surface, providing the opportunity for continuous catalysis. However, most COFs are amorphous due to their uncontrollable polymerization kinetics, which limits their suitability for continuous flow-through catalytic processes. In this work, spherical COFs microspheres were synthesized at room temperature and further pore walls modified by 1, 2-benzenedithiol (SCOFs-SH) to immobilize Au nanoparticles (Au NPs) for continuous flow-through catalysis. The optimized flux of the catalytic system was up to 3000 L· m⁻² ·h⁻¹ with a 4-nitrophenol reduction efficiency of 99 %. More importantly, the SCOFs-SH@Au NPs were proven to show good stability for 24 h flow-through testing and long-term stability for 15 days soaking in water. The reason for the fast catalysis could be ascribed to the design of SCOFs-SH@Au NPs to fast adsorption of 4-nitrophenol and the desorption of the product 4-aminophenol nearby the active sites. Our strategy, which leverages morphology and functional design to enhance catalytic efficiency, offers a promising approach for fabricating efficient heterogeneous catalysts for industrial applications.