Immobilization of Ag(0) nanoparticles on quaternary ammonium functionalized polyacrylonitrile fiber as a highly active catalyst for 4-nitrophenol reduction.

Ag(0) nanoparticles were immobilized on various pyridine salt, imidazole salt and quaternary ammonium functionalized polyacrylonitrile fibers (PANFs) to prepare Ag(0)-immobilized fiber catalysts. The catalytic activities of these immobilized catalysts for 4-nitrophenol (4-NP) reduction were detected. Among them, the quaternary ammonium fiber with butyl group immobilized Ag(0) nanoparticle catalyst PAN QA-C4 F-Ag(0) showed the best catalytic activity, and can effectively catalyze 4-nitrophenol (4-NP) reduction with a high conversation rate of 99.6%. Furthermore, PAN QA-C4 F-Ag(0) can be easily recovered, and it was reused 20 times with little decrease in catalytic activity and moderate Ag retention (53.5%). Notably, the cationic groups in the functionalized fibers can stabilize Ag(0) nanoparticles through electrostatic interactions and steric effects, and play an important role in phase transfer catalysis. Accordingly, possible mechanisms for the 4-NP reduction catalyzed by PAN QA-C4 F-Ag(0) were proposed.