Green synthesis and formation mechanism of cellulose nanocrystal-supported gold nanoparticles with enhanced catalytic performance

Deposition of precious metal catalysts onto the surface of various supporting materials to enhance the stability and catalytic activity is highly desired. Although extensive studies have been focused on the supported metal catalysts, their preparations are mainly based on the use of reducing agents which are not environmentally benign. Herein, we report a one-pot and green synthesis of gold nanoparticles (Au NPs) deposited on cellulose nanocrystals (CNs) under hydrothermal conditions using CNs as a reducing agent and stabilizing template. Our experimental results showed that the abundant electron-rich hydroxyl groups on the surface of CNs played a key role in the reduction and immobilization of Au NPs. The obtained nanohybrid catalyst exhibited much better catalytic activity and stability than the unsupported Au NPs and other Au-containing catalysts for the reduction of 4-nitrophenol. These findings pave the way for the green synthesis of bio-supported nanohybrid catalysts and can spur advancements in nanocellulose-based nanohybrids for their application in sensors, antibacterial materials and electronic devices.