Electrospun palladium/cellulose acetate composite nanofibers as a highly active and recyclable catalyst for Heck reactions

As one of the most abundant natural biopolymers on earth, cellulose offers unique advantages for developing sustainable catalytic supports due to its renewability, biocompatibility, and low cost. However, the weak chelating ability of its inherent hydroxyl groups for metal ions poses a significant challenge for stable palladium immobilization. Here, a physical encapsulation strategy was developed to embed palladium nanoparticles within cellulose acetate (CA) nanofibers (Pd@CA/PAAS) via electrospinning and subsequent thermal annealing, completely avoiding complex chemical modification. The resulting Pd@CA/PAAS catalyst was systematically characterized by FT-IR, SEM, HR-TEM, XPS, and ICP-AES. HR-TEM revealed uniformly dispersed palladium nanoparticles with diameters of 3 ∼ 5 nm, and XPS analysis confirmed that ∼78% of Pd2+ ions were reduced to catalytically active Pd0 species. The Pd@CA/PAAS catalyst exhibited excellent performance in Heck reactions of aryl iodides with alkenes, achieving product yields exceeding 85%. Remarkably, benefiting from the stable encapsulation within the cellulose fibrous matrix, the catalyst could be easily recovered by filtration and reused for 10 consecutive cycles with only 7.8% palladium leaching per run, retaining ∼89% yield even at the 10th cycle. This work provides a simple, low-cost, and green strategy for constructing stable and recyclable supported metal catalysts, offering great potential for sustainable heterogeneous catalysis.