Facile in situ synthesis of silver nanoparticles on procyanidin-grafted eggshell membrane and their catalytic properties.

Facile, efficient, and robust immobilization of metal nanostructures on porous bioscaffolds is an interesting topic in materials chemistry and heterogeneous catalysis. This study reports a facile in situ method for the synthesis and immobilization of small silver nanoparticles (AgNPs) at room temperature on natural eggshell membrane (ESM), which presents interwoven fibrous structure and can be used as a unique protein-based biotemplate. Procyanidin (Pro), a typical plant polyphenol extracted from grape seeds and skins, was first grafted onto ESM fibers to serve as both reductant and stabilizer during the synthesis process. As a result, the AgNPs were facilely synthesized and robustly immobilized on the ESM fibers without additional chemical reductant or physical treatments. The morphology and microstructure of the as-prepared AgNPs@Pro-ESM composites were characterized by combined microscopy and spectroscopy technologies. The results indicate that small AgNPs with mean diameter of 2.46 nm were successfully prepared on the Pro-ESM biotemplate. The composites exhibited good catalytic activity toward the reduction of 4-nitrophenol (4-NP). More importantly, these composite catalysts can be easily recovered and reused for more than eight cycles because of their high stability.