Combination of polymer and halloysite chemistry for development of a novel catalytic hybrid system

A covalent hybrid of halloysite-poly(methyl methacrylate-co-maleic anhydride) was prepared and applied for the immobilization of Pd nanoparticles. The hybrid system, Pd@Hal-Gua-Poly, was then characterized via TEM, TGA, ICP, BET, FTIR and XRD and successfully used as a heterogeneous catalyst for promoting two main Pd-catalyzed reactions, i.e. hydrogenation of nitro-arenes and Suzuki coupling reaction under mild and eco-friendly conditions. The study of recyclability of the catalyst confirmed high recyclability and low Pd leaching of Pd@Hal-Gua-Poly. Moreover, the hot-filtration test showed the heterogeneous nature of the catalysts. Notably, the comparison of the activity of the catalyst with that of Pd@Hal and Pd@Poly confirmed the superior catalytic activity of the former, indicating that the hybridization of Hal and Poly could lead to the improvement of the catalytic activity.