Enhancing Palladium Catalytic Performance Through Modification of Chitosan Nanofiber With Aldehyde Functional Groups

ABSTRACT Chitosan (CS) is a widely distributed and abundant biopolymer in nature. In this study, CS was blended with poly(methacrylic acid) (PMAA) to prepare stable chitosan composite nanofibers (CS/PMAA) via electrospinning, followed by annealing. The nanofibers were then functionalized through Schiff base reactions between CS amino groups and aldehydes and used to support palladium catalysts. Their catalytic performance was evaluated by the Heck reactions. Notably, the Pd 2+ ions anchored on the CS/PMAA nanofibers exhibited higher activity than those on the 2‐pyridylimino‐functionalized chitosan nanofibers (2PyCS/PMAA). In contrast, the Pd 0 species supported on the 2PyCS/PMAA nanofibers showed outstanding catalytic activity and remarkable reusability. HR‐TEM was utilized to monitor the morphological changes and Pd 0 nanoparticle contents on the CS/PMAA and 2PyCS/PMAA nanofibers during reuse. Chelating interactions between the nanofibers and Pd 2+ ions were studied by FT‐IR, adsorption distribution analysis, XRD, and HR‐TEM. The strong nucleophilic affinity of Pd 2+ ions for the CS nanofibers was further verified by PALS. In conclusion, this work presents an effective and straightforward approach for preparing highly active and stable supported palladium catalysts.