Cellulose/β-cyclodextrin hydrogel supported metal nanoparticles as recyclable catalysts in the 4-nitrophenol reduction, Suzuki–Miyaura coupling and click reactions.

Metal nanoparticles have been widely used for catalysis because of its excellent catalytic activity and selectivity. Green and sustainable supports play a quite important role in the enhancement of the efficiency and recyclability of metal nanoparticles. Here, a cellulose/β-cyclodextrin hydrogel is applied to support tannic acid-encapsulated metal (such as Ag, Au, Pd and Cu) nanoparticles to generate nanocomposite hydrogels for catalysis. TEM analysis indicates that these metal nanoparticles have the average diameters of 6.5 nm for Au nanoparticles, 7.0 nm for Ag nanoparticles, 5.0 nm for Pd nanoparticles and 4.0 nm for Cu nanoparticles, respectively. The catalytic activities of the as-prepared metal nanocomposite hydrogels are estimated in a series of chemical reactions in the aqueous system. The recyclability, applicability and generality of these nanocomposite hydrogels are also well investigated. The nanocomposite hydrogels can be reused for at least 10 times in the 4-nitrophenol reduction, 8 times for Suzuki–Miyaura coupling reaction and 6 times for click reaction, respectively. Furthermore, good yields are obtained in the catalytic process. This study gives a green and sustainable strategy to support metal nanoparticles with good catalytic activity and recyclability. [ABSTRACT FROM AUTHOR]