Cellulose/silver nanoparticles composite microspheres: eco-friendly synthesis and catalytic application

Cellulose/silver nanoparticles (Ag NPs) composites were prepared and their catalytic performance was evaluated. Porous cellulose microspheres, fabricated from NaOH/thiourea aqueous solution by a sol-gel transition processing, were served as supports for Ag NPs synthesis by an eco-friendly hydrothermal method. The regenerated cellulose microspheres were designed as reducing reagent for hydrothermal reduction and also micro-reactors for controlling growth of Ag NPs. The structure and properties of obtained composite microspheres were characterized by Optical microscopy, UV-visible spectroscopy, WXRD, SEM, TEM and TG. The results indicated that Ag NPs were integrated successfully and dispersed uniformly in the cellulose matrix. Their size (8.3-18.6 nm), size distribution (3.4-7.7 nm), and content (1.1-4.9 wt%) were tunable by tailoring of the initial concentration of AgNO3. Moreover, the shape, integrity and thermal stability were firmly preserved for the obtained composite microspheres. The catalytic performance of the as-prepared cellulose/Ag composite microspheres was examined through a model reaction of 4-nitrophenol reduction in the presence of NaBH4. The composites microspheres exhibited good catalytic activity, which is much high than that of hydrogel/Ag NPs composites and comparable with polymer core-shell particles loading Ag NPs.