Preparation of thermal stable supported metal (Cu, Au, Pd) nanoparticles via cross-linking cellulose gel confinement strategy

Abstract Hydrogel is low-cost porous material that has been used as effective support for confining metal nanoparticles due to its interconnected three-dimensional (3D) networks. Cellulose gel with covalently crosslinking has good thermal stability and can be used as support to stabilize metal nanoparticles in the high temperature environment. In this work, (Cu, Pd, Au) nanoparticles were immobilized on covalently crosslinked cellulose gel via adsorption and in situ reduction, followed by pyrolysis to obtain carbon-supported metal nanoparticles. Typically, the Cu nanoparticles were highly dispersed in the gels due to the interconnected networks and functional groups that restricted the aggregation of metal nanoparticles and improved the stability of the gel framework during pyrolysis. The results were confirmed by XRD, TEM, XPS, and FT-IR analyses. Furthermore, the Cu NPs exhibited good catalytic activity and selectivity for the hydrogenation of nitroaromatics with a TOF of 6656 h-1, which was comparable to previously reported Pd catalysts. The catalyst remained its activity after 10 recycles, demonstrating the high stability and activity of the Cu NPs prepared by this method. This work provides a green synthetic pathway for the construction of size-controlled metal nanoparticles immobilized on a carbon support.