Sulfhydryl-Functionalized Covalent Organic Framework Immobilized Au Nanoparticles for Flow-through 4-Nitrophenol Hydrogenation

Sulfhydryl covalent organic frameworks (COFs-SH) exhibit great potential as active substrates to limit the size of noble metal nanoparticles within the pores and accelerate electron transfer in catalytic hydrogenation. However, the application of these COFs-SH-based catalysts in achieving efficient and continuous catalytic hydrogenation remains challenging, primarily owing to the complexity of postprocessing procedures and the difficulties associated with controlling their morphology. This study presented a one-step synthesis for tailoring the morphology and functionalization of COFs via a reversible polycondensation-termination method through aniline incorporation. COFs-SH with sheets, fibers, and spheres were obtained. The spherical COFs-SH were selected to immobilize tiny Au NPs (3 nm) and flow-through catalysis toward 4-nitrophenol due to their strong pressure resistance and stability under the flow-through process. The permeation flux reached 2500 L m –2 h –1, and the reduction efficiency for 4-nitrophenol exceeded 99%. Furthermore, Au NPs anchored to GCOFs-SH-based materials exhibited a long-term Au release process with rechargeability after depletion, demonstrating their strong sustainable catalytic hydrogenation ability. Our facile approach to addressing application problems may pave the way to highly efficient catalysis.