Facile synthesis of palladium and gold nanoparticles by using dialdehyde nanocellulose as template and reducing agent.

Cellulose nanofibrils (CNFs) were firstly prepared by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidation and further oxidized to 2,3-dialdehyde nanocelluloses (DANCs) by periodate oxidation. Furthermore, by using DANCs as reducing as well as stabilizing agent, palladium (Pd) and gold (Au) nanoparticles (NPs) supported on nanocellulose (PdNPs@NC and AuNPs@NC) were synthesized, respectively. The reduction of Pd or Au ions to its metallic form by DANCs was confirmed by UV-vis spectra, XRD, and XPS. TEM results showed that Pd and Au NPs were homogenously deposited onto cellulose nanofibrils, respectively. The catalytic performance of PdNPs@NC was further investigated by Suzuki coupling reaction. The product yield of the Suzuki coupling reaction between aryl bromides and phenyl boronic acid was more than 90% after 1 h with 0.1 mol% PdNPs@NC catalyst, which demonstrated that the synthesized PdNPs@NC nanohybrid could be successfully applied in Suzuki coupling reaction with an efficient catalytic activity.