Preparation of Silver Nanoparticles Deposited on TEMPO-Oxidized Cellulose Nanofibers

Silver nanoparticles (AgNPs) were synthesized by a chemical method in which cellulose
nanofibers (CNFs) extracted from pineapple leaves served as a stabilizing and reducing agent. In
this study, pineapple leaves were oxidized by the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-
mediated oxidation with sodium hypochlorite (NaClO) to obtain CNFs. After the oxidation, the
transformation from hydroxyl groups to carboxylate groups of cellulose was confirmed by Fouriertransform
infrared spectroscopy (FTIR), and TEMPO-oxidized CNFs with a higher carboxylate
content were obtained. Then, TEMPO-oxidized CNFs with a carboxylate content of 2.49 mmol/g
and non-oxidized CNFs with a carboxylate content of 0.68 mmol/g were used as a reducing agent to
synthesize AgNPs. The formation of AgNPs was confirmed by color changes of the Ag solutions
from white to yellow. Furthermore, AgNPs with an average diameter of 76.5 ± 22.15 nm were
obtained when TEMPO-oxidized CNFs were used as a reducing agent, while non-oxidized CNFs
generated AgNPs with a larger particle size of 181.2 ± 66.16 nm. This suggested that the TEMPOoxidized
CNFs could be used as a stabilizing and reducing agent for the synthesis of AgNPs with
smaller diameters.