Facile in situ synthesis of noble metal nanoparticles in porous cellulose fibers

In situ synthesis of noble metal (Ag, Au, Pt, Pd) nanoparticles was carried out under ambient conditions in porous cellulose fibers as nanoreactors. Particles of less than 10 nm were readily prepared using the described approach, and monodisperse nanoparticles were obtained under an optimized concentration of the metal precursor solution. The nanoporous structure and the high oxygen (ether and hydroxyl) density of the cellulose fiber constitute an effective nanoreactor for in situ synthesis of metal nanoparticles. The nanopore is essential for incorporation of metal ion and reductant into cellulose fibers as well as for removal of unnecessary byproducts from fibers. This was endorsed by negligible adsorption of metal ion onto nonporous films of poly(vinyl alcohol) and starch. The ether oxygen and the hydroxyl group not only anchor metal ions tightly in cellulose fibers via ion-dipole interactions, but they also stabilize metal nanoparticles by strong bonding interaction with their surface atoms. The preparative procedure is facile and versatile, and provides a simple route to manufacturing of useful noble metal nanoparticles.