Synthesis of Hydroxylatopillar[6]arene-Controlled Gold Nanoparticles-Cellulose Nanocrystals and Their Applications.

In this work, two macrocyclic hosts, named hydroxylatopillar[6]arene and dihydroxylatopillar[6]arene (HP6, 2HP6), are proposed. We found that the reduction of Au3+ to Au0 can success by using HP6 or 2HP6 as a reductant and stabilizing agent. At the end of HP6/2HP6, hydroxyl (-OH) groups were used as a reductant to reduce Au3+ to Au0. At the same time, -OH on HP6/2HP6 was oxidized to -COOH, and then the formed -COOH can be used as the stabilizer to prevent the infinite growth of AuNPs. The cellulose nanocrystals (CNCs) prepared by a clean and nonpolluting method were used as carriers to load AuNPs on them. The CNCs were applied for the adsorption of methylene blue (MB), and then the MB was catalytically degraded by HP6/2HP6-AuNPs-CNC. Besides, the HP6/2HP6-AuNPs-CNC showed remarkable catalytic performance for reducing nitro to the amino group in 4-nitrophenol. The advantages of clean and green synthesis make the HP6/2HP6-AuNPs-CNC a hybrid material and its application sustainable.