▎ 摘　　要

In this study, a nanocomposite of Fe3O4@GO@Zn-Ni-Fe-layered double hydroxide was synthesized as a novel and efficient mesoporous magnetic nanocatalyst. The synthesis was carried out via the immobilization of Fe3O4 MNPs (magnetic nanoparticles) on graphene oxide and then the layering of Zn-Ni-Fe-layered double hydroxide moieties on the constituents of Fe3O4@GO. The magnetic graphene oxide/layered double hydroxide system was then characterized using SEM, EDX, FTIR, XRD, TEM and VSM analyses. The catalytic activity of the prepared composite system was further studied towards one-pot Knoevenagel-Michael reaction of aromatic aldehydes with 4-hydroxycoumarin in water. All reactions were carried out under reflux conditions giving biscoumarin materials in 87-95% yields within 3-40 min. This method has noteworthy advantages in terms of mild reaction conditions, short reaction times, utilizing water as an environmental friendly solvent and applying a magnetically separable catalyst system.